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This thesis focuses on boron-based materials, notable for their structural complexity and unique combination of ceramic and metallic properties. These properties typically result in materials with high mechanical strength, electrical conductivity, and melting points. Among these materials are MAB phases, a family of layered materials comprised of a transition metal (M), an A-element (typically an element from Group 13-14), and boron (B). The layered nature of these materials provides a pathway towards the realization of 2D materials, coined MBenes (or boridene), through chemical exfoliation. While the potential for discovering novel materials is immense, their realization often demands extensive experimental efforts. Theoretical models may here be used as a filter by guiding experimental endeavours. The work presented herein aims to leverage theoretical models and to develop frameworks suitable for reliable thermodynamical predictions in hope of the discovery of additional boron-based materials. First-principles calculations, particularly density functional theory (DFT), have extensively been employed in this thesis to determine the ground state energy of materials and predict their stability or tendency to decompose. However, first-principles calculations typically rely on a pre-defined crystal structure which may be constructed through a priori information or obtained through the use of crystal structure prediction (CSP) frameworks. We herein explore both of these approaches by i) systematically substituting elements in known low-energy structures, and ii) deriving novel low-energy structures by combining CSP with cluster expansion (CE) models. The first approach is herein exemplified when considering the low-energy structures of V3B2 (P4/mbm) and Cr5B3 (I4/mbm). These structures are comprised of two M-sites in addition to boron and thus form the general compositions M’2M’’B2 and M’4M’’B3, respectively. In a follow-up project, this approach was refined by probing, Funding agencies: The Swedish Research Council (grant numbers 2019-05047, 2022-06099, 2022-06725 and 2018-05973) and the Knut and Alice Wallenberg (KAW) foundation (grant number KAW 2020.0033)

The electrification and digitalization of our society has propelled the demand for energy storage solutions. High-end technologies have been developed to satisfy the requirements of demanding applications, such as electromobility and portable consumer electronics, which also increasingly find markets for less demanding applications. These markets include grid and domestic energy storage, as well as Internet of Things (IoT). However, using high-end technologies for low-end applications is a waste of resources that puts unnecessary stress on the supply lines. Thus, more low-cost cost and environmentally friendly alternative technologies are sought, among which renewable biobased materials derived from agriculture and forestry play a prominent role. The dominant chemical constituents in plants, cellulose and lignin, exhibit some intriguing electrochemical and colloidal properties. Cellulose has been found to efficiently stabilize various electronic materials, whereas lignin can be used as an electronic material itself. Lignocellulosic materials also open for papermaking as an alternative manufacturing approach. Taking the step to using papermaking methods is, however, a bit far from the technology readiness level, as the vast majority of the research on paper electrodes is based on nanocellulose. The material properties of such nanopapers are indeed extraordinary, but the lack of large-scale production methods for nanopapers is a serious challenge. To circumvent this obstacle and find a shortcut to the realization of paper electrodes, this thesis has turned to conventional papermaking techniques. Fibres are essentially different to nanofibrils by their difference in size, and the papermaking process requires careful composition of the formulations. Thus, as the research on nanopaper electrodes cannot be directly translated into conventional papermaking techniques, this calls for separate studies on fibre-based systems. This thesis is based on four separate works carrie

Reversible solid oxide cells (rSOCs) present a promising solution to future energy challenges through the efficient conversion between electrical and chemical energy. To date, the benefits of rSOC technology have been off-limits to portable power and electrolysis applications due to the excessive polarisation resistance of the oxygen electrode at low temperatures, characterised by high area specific resistance (ASR) values below 500 degrees C. In this work we demonstrate growth of symmetric and complete rSOC structures based on state-of-the-art vertically aligned nanocomposite (VAN) films grown by pulsed laser deposition (PLD) on porous Pt-coated anodised aluminium oxide (AAO) substrates. The symmetric rSOC structures give the first demonstration of an rSOC oxygen electrode with ASR below 0.1 ohm cm2 at temperatures less than 450 degrees C. This is achieved through oxygen vacancy tuning by annealing, as confirmed by Time-of-Flight Elastic Recoil Detection Analysis (ToF-ERDA) and Rutherford Backscattering Spectrometry (RBS) measurements. Thus, the present work describes a promising route towards future high-performance rSOC devices for portable power applications., Funding Agencies|European Union; Royal Academy of Engineering Chair in Emerging technologies [101017709]; EPSRC Centre of Advanced Materials for Integrated Energy Systems (CAM-IES) [CIET1819_24]; EU-H2020-ERC-ADG EROS [EP/P007767/1]; EPSRC [882929]; Sir Henry Royce Institute [EP/R513180/1]; U.S. National Science Foundation [EP/R00661X/1]; Swedish Research Council (VR) [DMR-1809520, DMR-2016453]; [2019-00191]; [2021-00357]

This thesis focuses on providing insights into energy-efficient ways of growing protective thin films using physical vapor deposition (PVD) by magnetron sputtering, specifically high-power impulse magnetron sputtering (HiPIMS). This technique involves ionizing the material to be deposited to a high degree. The properties of the film for applications such as protective coatings could thus be controlled by modulating the energy and guiding the ions using electric and magnetic fields, respectively. The multiprincipal element TiZrNbTa nitride system is of interest for its corrosion-resistant coating applications. This material system consists of refractory metals that exhibit different ionic charge states with significant mass contrast. Thus, when sputtered with HiPIMS, the properties of the films strongly depend on the mass and energy of the bombarding metal ions. The transport of these ions to the substrate is influenced by the magnetic field distribution in the chamber. To demonstrate the influence of the magnetron arrangement, the deposition is performed without external heating. Two magnetron arrangements were chosen: a tilted closed-field design with four magnetrons and a single magnetron. The films exhibited different properties depending on the magnetron design used. The single magnetron design induces changes in the preferred orientation of the films from 111 to 200 along with film composition and density. A reduction in residual stress was observed with only a ~6 % degradation in the hardness compared to the closed-field design. I also demonstrate epitaxial growth of TiZrNbTaNx films without external heating. The films were grown with a single magnetron design on single crystal sapphire substrate. Applying a pulsed substrate bias with a long pulse width instead of a constant bias, resulted in low argon (~1 at. %) and oxygen (0.5 at. %) content in the films. In addition, the films exhibited a higher optical absorbance in the near-infrared region than th, Funding: The work is supported financially by the VINNOVA Competence Centre FunMat-II (Grant No. 2022-03071), the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linköping University (Faculty Grant SFO-Mat-LiU No. 2009 00971), the Knut and Alice Wallenberg foundation through the Wallenberg Academy Fellows program (KAW-2020.0196), the Swedish Research Council (VR) under Project No. 2021-03826, and the Swedish Energy Agency under Project No. 52740-1.

Electrocatalysis enables the industrial transition to sustainable production of chemicals using abundant precursors and electricity from renewable sources. De-centralized production of hydrogen peroxide (H2O2) from water and oxygen of air is highly desirable for daily life and industry. We report an effective electrochemical refinery (e-refinery) for H2O2 by means of electrocatalysis-controlled comproportionation reaction (2(H)O + O -> 2(HO)), feeding pure water and oxygen only. Mesoporous nickel (II) oxide (NiO) was used as electrocatalyst for oxygen evolution reaction (OER), producing oxygen at the anode. Conducting polymer poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) drove the oxygen reduction reaction (ORR), forming H2O2 on the cathode. The reactions were evaluated in both half-cell and device configurations. The performance of the H2O2 e-refinery, assembled on anion-exchange solid electrolyte and fed with pure water, was limited by the unbalanced ionic transport. Optimization of the operation conditions allowed a conversion efficiency of 80%., Funding: Swedish Agency for Innovation Systems (Vinnova) [2016-05156]; Swedish Energy Agency [42022-1]; Swedish Research Council [VR 2021-04427, VR 2019-05577, VR 2016-05990]; Centre in Nanoscience and Technology (CeNano, Linkoeping Institute of Technology (LiTH), Linkoeping University, 2020, 2021); Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoeping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Knut and Alice Wallenberg Foundation (H2O2) [KAW 2018.0058]

As the core component of sandwich-like perovskite solar cells (PSCs), the quality of perovskite layer is a challenge for further progress in PSCs due to the unfavorable defects and uncontrollable crystallization. Here, a surface post-treatment strategy employing ethyl thioglycolate (ET) as ligand molecule is developed for property manipulation of perovskite films. ET can lower surface energy of perovskite facets and induces secondary growth of grains, giving films with higher crystallinity and lower defect density. Meanwhile, both carbonyl and sulfhydryl in ET can bind to the Pb2+, thus forming bidentate anchoring on the surface for defect passivation. Besides, the perovskite/ET/C60 interface presents improved charge transfer owing to the well-aligned energy levels. Consequently, the power-conversion-efficiency (PCE) is boosted to 22.42% and 23.56% (certified 23.29%) for the FA0.85Cs0.15Pb(I0.95Br0.05)3 and FA0.9MA0.05Cs0.05Pb(I0.95Br0.05)3 PSCs, respectively, and the FA0.85Cs0.15Pb(I0.95Br0.05)3-based PSC with a larger area (1.03 cm2) delivers a PCE of 20.01%. Importantly, ET demonstrates effective management of I2 and PbI2, thereby preventing accelerated degradation and lead leakage of devices. Thanks to the multiple effects of ET, the resulting devices exhibit significantly enhanced ambient stability over a course of 800 h, and a thermal stability of over 1500 h while maintaining 80.4% of its original efficiency. The efficient and stable inverted perovskite solar cells are developed by introducing ethyl thioglycolate for synergistic crystallization modulation, surface passivation and interfacial PbI2/I2 management. image, Funding Agencies|Jiaxing Public Welfare Research Project; Zhejiang Provincial Natural Science Foundation of China [LQ23E030005, LGJ22B040001, KYZ044123045CZ]; Zhejiang Provincial Postdoctoral Science Foundation [ZJ2022148]; Innovation JiaxingElite leading plan 2020; National Key Research and Development Program of China [2022YFB4200904]; [2022AY10003]

In the domain of organic mixed ionic-electronic conductors (OMIECs), simultaneous transport and coupling of ionic and electronic charges are crucial for the function of electrochemical devices in organic electronics. Understanding conduction mechanisms and chemical reactions in operational devices is pivotal for performance enhancement and is necessary for the informed and systematic development of more promising materials. Surface-enhanced Raman spectroscopy (SERS) is a potent tool for monitoring electrochemical evolution and dynamic doping in operational devices, offering enhanced sensitivity to subtle spectral changes. We demonstrate the utility of SERS for in situ tracking of doping in OMIECs in an organic light-emitting electrochemical cell (LEC) containing a conjugated polymer (poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]; MEH-PPV), a molecular anion (lithium triflate), and an electrolyte network (poly(ethylene oxide); PEO). SERS enhancement is achieved via an interleaved layer of gold particles formed by spontaneous breakup of a deposited thin gold film. The results successfully highlight the ability of SERS to unveil time-resolved MEH-PPV doping and polaron formation, elucidating the effects of triflate ion transfer in the operating device and validating the electrochemical doping model in LECs., Funding Agencies|Stiftelsen f?r?Strategisk Forskning [ITM17-0316]; Swedish Foundation for Strategic Research (SSF) [2016-05990]; Knut and Alice Wallenberg Foundation (KAW)

MAB phases (MABs) are atomically-thin laminates of ceramic/metallic-like layers, having made a breakthrough in the development of 2D materials. Though offering a vast chemical and phase space, relatively few MABs have been synthesised. To guide experiments, we perform high-throughput ab initio screening of MABs that combine group 4-7 transition metals (M); Al, Si, Ga, Ge, or In (A); and boron (B) focusing on their phase stability trends and mechanical properties. Considering the 1:1:1, 2:1:1, 2:1:2, 3:1:2, 3:1:3, and 3:1:4 M:A:B ratios and 10 phase prototypes, synthesisability of a single-phase compound for each elemental combination is estimated through formation energy spectra of competing dynamically stable MABs. Based on the volumetric proximity of energetically-close phases, we identify systems in which volume-changing deformations may facilitate transformation toughening. Subsequently, chemistry- and phase-structure-related trends in the elastic stiffness and ductility are predicted using elastic-constants-based descriptors. The analysis of directional Cauchy pressures and Young's moduli allows comparing mechanical response parallel and normal to M-B/A layers. The suggested promising MABs include Nb 3 AlB 4 , Cr 2 SiB 2 , Mn 2 SiB 2 or the already synthesised MoAlB., Funding Agencies|Austrian Science Fund, FWF [10.55776/T1308]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoeping University SFO-Mat-LiU [2009 00971]; Knut and Alice Wallenberg Foundation Scholar [KAW2016.0358, KAW2019.0290]; Swedish Research Council (VR) [VR-2021-04426]; Competence Center Functional Nanoscale Materials (FunMat-II) [2022-03071]; Swedish Research Council [2022-06725, 2018-05973]; Vienna Scientific Cluster (VSC) in Austria; TU Wien Bibliothek

Gas bubble evolution is an important phenomenon in many electrochemical processes and it is highly sensitive to the surface properties. Here we visualize the gas bubble dynamics on the surface of different graphene substrates during hydrogen evolution reaction (HER) using atomic force microscopy combined with scanning electrochemical microscopy. The low overpotential and low surface hydrophobicity of few-layer graphene formed on Cphase SiC causes the uniform distribution of hydrogen nanobubbles, which easily depart from the surface during the reaction. Conversely, the high overpotential and more hydrophobic surface of HOPG induces hydrogen bubbles to linger on the surface for an extended duration, leading to its accumulation and the subsequent formation of microbubbles. This in-situ nanoscale electrochemical mapping of hydrogen bubble dynamics provides new insight into electrocatalytic HER that occurs on non-metal electrodes., Funding Agencies|Ministry of Science and Technology [MOST 107-2113-M-001-010-MY3, MOST 111-2124-M-001-001, MOST 112-2112-M-131-003, MOST 111-2112-M-131-003]; National Science and Technology Council (NSTC) of Taiwan-Science Vanguard Project [NSTC 111-2123-M-002-009]; Academic Summit Project [NSTC 112-2639-M-002-005-ASP]; Academia Sinica [AS-SS-106-02-3]; I-MATE program in Academia Sinica; Center of Atomic Initiative for New Materials (AI-Mat) , National Taiwan University , from the Featured Areas Research Center Program within Ministry of Education (MOE) in Taiwan [111L9008, 112L9008]; JSPS KAKENHI Grant [JP19H05814, JP23H00301]; JST PRESTO Grant [JPMJPR2274]; Chang Gung University [URRPD2N0021]

Reversibly switching visible light excited phosphorescence emission by external stimuli is highly challenging. Herein, we report a series of tetrakis(arylthio)benzene derivatives with a D-A structure, exhibiting visible-light excited room-temperature phosphorescence. Significantly, the emission from their crystalline powder state responded to mechanical forces, attributed to alterations in molecular stacking changes, resulting in their phosphorescence color changes. Moreover, the monomer and aggregated phosphorescence transition could be reversibly switched by temperature when doping these molecules into a phase-changing matrix saturated fatty acid (FA) because the FA matrix is transformed between solid and fluid states under different temperatures. In addition, multi-color luminescent materials were also obtained by further introducing triphenylamine dye molecules. Finally, these doping systems exhibited excellent application potential in temperature indication and anti-counterfeiting. This successful design strategy provides a new idea for preparing reversible external stimuli-responsive phosphorescent materials. D-A-type tetrakis(arylthio)benzene derivatives exhibited visible-light excited phosphorescence, mechanical-stimuli responsive phosphorescence in solid and temperature-induced phosphorescence changes in the phase-changing doping state., Funding Agencies|Fundamental Research Funds for the Central Universities [2232022A-03, 2232022G-04]; National Natural Science Foundation of China [22375036, 21975046]; Natural Science Foundation of Shanghai [21ZR1402000]; International Cooperation Fund of Science and Technology Commission of Shanghai Municipality [21130750100]; Swedish Research Council [2020-04600, 2022-06725]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University [2009-00971]

Wurtzite-type aluminum nitride (AlN) thin films exhibiting high thermal conductivity, large grain size, and low surface roughness are desired for both bulk acoustic wave and surface acoustic wave resonators. In this work, we use ammonia (NH3) assisted reactive sputter deposition of AlN to significantly improve these properties. The study shows a systematic change in the structural, thermal, and morphological properties of AlN grown in nitrogen (N2) and N2 + NH3 atmosphere. The study demonstrates that NH3 assisted AlN sputtering facilitates 2D growth. In addition, the study presents a growth model relating the 2D growth to improve the mobility of aluminum (Al) and nitrogen (N) ad-atoms in NH3 atmosphere. Consequently, the thermal conductivity and roughness improve by approximate to 76%, and approximate to 35%, while the grain size increases by approximate to 78%., Funding Agencies|BMVIT; BMDW; Austrian provinces of Carinthia and Styria; Swedish Governmental Agency for innovation systems (VINOVA) under the Competence Center Program [2022-03139]; Swedish Research Council VR [2023-04993]

Aluminum (Al)-ion batteries have emerged as a potential alternative to conventional ion batteries that rely on less abundant and costly materials like lithium. Nonetheless, given the nascent stage of advancement in Al-ion batteries (AIBs), attaining electrode materials that can leverage both intercalation capacity and structural stability remains challenging. Herein, we demonstrate a C3N4-derived layered N,S heteroatom-doped carbon, obtained at different pyrolysis temperatures, as a cathode material for AIBs, encompassing the diffusion-controlled intercalation and surface-induced capacity with ultrahigh reversibility. The developed layered N,S-doped corbon (N,S-C) cathode, synthesized at 900 degrees C, delivers a specific capacity of 330 mAh g(-1) with a relatively high coulombic efficiency of similar to 85% after 500 cycles under a current density of 0.5 A g(-1). Owing to its reinforced adsorption capability and enlarged interlayer spacing by doping N and S heteroatoms, the N,S-C900 cathode demonstrates outstanding energy storage capacity with excellent rate performance (61 mAh g(-1) at 20 A g(-1)) and ultrahigh reversibility (90 mAh g(-1) at 5 A g(-1) after 10 000 cycles)., Funding Agencies|National Natural Science Foundation of China; SSF Synergy Program [EM16-0004]; Swedish Research Council [2022-06725]; [52203092]

Face -centered cubic transition metal carbides exhibit high melting points and hardness, making them prominent candidates for protective coating applications. Vanadium carbide (VC) has typical characteristics of transition metal carbides. It serves as model material in this study, in which we showcase the effect of superlattice architecture on mechanical properties and fracture toughness. While beneficial effects of superlattice arrangement have been demonstrated for a series of nitride -based coatings, transition metal carbides remain largely unexplored territory. Following density functional theory based ab initio predictions on lattice and shear modulus mismatch, we develop VC/ZrC and VC/HfC superlattice coatings synthesized via pulsed DC sputter deposition. The bilayer periods ( Lambda ) of our fully fcc-structured polycrystalline coatings range between 2 - 50 nm (indicated by X-ray diffraction, transmission and scanning electron microscopy). The chemical composition is close to 1:1 stoichiometry (from X-ray fluorescence, elastic back -scattering spectrometry and elastic recoil detection analysis). Both superlattice series exhibit a strong dependence of hardness, elastic modulus, and fracture toughness on their bilayer periods, which can only be correlated with the in -plane stress variations for VC/ZrC. The VC/HfC superlattices provide their peak -hardness of 36.0 +/- 1.6 GPa for Lambda = 6 nm and their peak in fracture toughness of 3.5 +/- 0.5 MPa root m for Lambda = 10 nm., Funding Agencies|Swedish Research Council [2022-06725]; Vienna Scientific Cluster (VSC) in Austria; RADIATE (Research And Development with Ion Beams - Advancing Technology in Europe) project

Transition metal phosphides have been demonstrated to be promising non -noble catalysts for water splitting, yet their electrocatalytic performance is impeded by unfavorable free energies of adsorbed intermediates. The achievement of nanoscale modulation in morphology and electronic states is imperative for enhancing their intrinsic electrocatalytic activity. Herein, we propose a strategy to expedite the water splitting process over NiCoP/FeNiCoP hollow ellipsoids by modulating the electronic structure and d -band center. These unique phosphorus (P) vacancies -rich ellipsoids are synthesized through an ion -exchange reaction between uniform NiCo-nanoprisms and K 3 [Fe(CN) 6 ], followed by NaH 2 PO 2 -assisted phosphorization under N 2 atmosphere. Various characterizations reveals that the titled catalyst possesses high specific surface area, abundant porosity, and accessible inner surfaces, all of which are beneficial for efficient mass transfer and gas diffusion. Moreover, density functional theory (DFT) calculations further confirms that the NiCoP/FeNiCoP heterojunction associated with P vacancies regulate the electronic structures of d -electrons and p -electrons of Co and P atoms, respectively, resulting in a higher desorption efficiency of adsorbed H* intermediates with a lower energy barrier for water splitting. Due to the aforementioned advantages, the resultant NiCoP/FeNiCoP hollow ellipsoids exhibit remarkably low overpotentials of 45 and 266 mV for hydrogen and oxygen evolution reaction to achieve the current densities of 10 and 50 mA cm -2 , respectively. This work not only reports the synthesis of a hollow double -shell structure of NiCoP/FeNiCoP but also introduces a novel strategy for constructing a multifunctional electrocatalyst for water splitting., Funding Agencies|National Natural Science Foundation of China [12275168, 12075148]; Local capacity building project of Shanghai Science and Technology Committee [21010500300]; Shanghai Science and Technology Young Talents Sailing Program [23YF1412900]; STINT Joint China-Sweden Mobility Project [CH2017-7243]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University (SFO-Mat-LiU) [2009 0097]

We use reactive DC magnetron sputtering to showcase synthesis strategies for multicomponent carbides with the NaCl-type fcc structure and illustrate how deposition conditions allow controlling the formation of metallic and ceramic single phases in the Cr-Hf-Mo-Ta-W system. The synthesis is performed in argon flow and different acetylene flows from 0 to 12 sccm, at ambient and elevated temperatures (700 degrees C), respectively, hindering/promoting the adatom diffusion. Structural and microstructural investigations reveal the formation of the bcc metallic phase ( a = 3.188 - 3.209 & Aring;) in films deposited without acetylene flow, also supported by ab initio density function theory (DFT) analysis of lattice parameters as a function of the C content. Experimentally, a bcc-to-fcc phase transition is observed through the formation of an amorphous coating. Contrarily, samples deposited in higher acetylene flow show an fcc multielement carbide phase ( a = 4.33 - 4.49 & Aring;). The crystalline films reveal columnar morphology, while the amorphous ones are very dense. We report promising mechanical properties, with hardness up to 25 +/- 1 GPa. The indentation moduli reach up to 319 +/- 6 GPa and show trends consistent with DFT predictions. Our study paves the path towards the preparation of Cr-Hf-Mo-Ta-W multicomponent carbides by magnetron sputtering, showing promising microstructure as well as mechanical properties., Funding Agencies|Ministry of Education, Youth and Sports of the Czech Republic [LM2018097]; Czech Science Foundation [GA23-05947S]; European Structural and Investment Funds [VEKOP-2.3.3-15-2016-00002, VEKOP-2.3.2-16-2016-00011]; Austrian Science Fund; FWF [T-1308]; Swedish Research Council [2022-06725, 2018-05973]; Vienna Scientific Cluster (VSC) in Austria [T-1308, 2022-06725]

Nanoscale hybrid inorganic-organic multilayers are attractive for accessing emergent phenomena and properties through superposition of nanomolecularly-induced interface effects for diverse applications. Here, we demonstrate the effects of interfacial molecular nanolayers (MNLs) of organo-diphosphonates on the growth and stability of titania nanolayers during the synthesis of titania/MNL multilayers by sequential atomic layer deposition and single-cycle molecular layer deposition. Interfacial organo-diphosphonate MNLs result in similar to 20-40% slower growth of amorphous titania nanolayers and inhibit anatase nanocrystal formation from them when compared to amorphous titania grown without MNLs. Both these effects are more pronounced in multilayers with aliphatic backbone-MNLs and likely related to impurity incorporation and incomplete reduction of the titania precursor indicated by our spectroscopic analyses. In contrast, both MNLs result in two-fold higher titania nanolayer roughness, suggesting that roughening is primarily due to MNL bonding chemistry. Such MNL-induced effects on inorganic nanolayer growth rate, roughening, and stability are germane to realizing high-interface-fraction hybrid nanolaminate multilayers., Funding Agencies|Division of Civil, Mechanical and Manufacturing Innovation [CMMI 2135725]; US National Science Foundation [2009 00971]; Swedish Government Strategic Research Area in Materials Science on Functional Materials grant SFO-Mat-LiU [KAW-2020.0196]; Knut and Alice Wallenberg foundation through the Wallenberg Academy Fellows grant [2021-03826]; Swedish Research Council through the VR [DST/INT/SWD/VR/P-18/2019]; DST India [RGPIN-2019-06213]; NSERC

When it comes to sustainable and efficient energy solutions, organic semiconductors can play an important role in thermoelectric applications, since they are non-toxic, cheap, made of abundant chemical species, and show intrinsically low thermal conductivities. Their electrical conductivity can be optimized via doping. Yet, thermal conduction should be as low as possible and, to this end, the atomic scale mechanisms behind heat transport -e.g. the correlation between morphology and thermal conductivity or the role of doping- should be understood in detail. Fully atomistic molecular dynamics calculations of the lattice thermal conductivity of doped poly(3,4-ethylenedioxythiophene) (PEDOT) highly ordered, quasi-crystalline nanofibers are presented here. It is found that the conductivity along the backbone direction is not necessarily the highest, but it depends on the length of the PEDOT chains, thus the degree of anisotropy depends on the the aspect ratio of the nanofiber. Indeed, transport along the lamellar direction can be of the same order or higher than that of the backbone if their lengths are comparable. These results challenge the usual expectation that thermal conduction along the backbone largely exceeds those along the lamellar and pi - pi direction and have the important consequence that the anisotropy could be leveraged in thermal management applications. Lattice thermal conduction in highly ordered PEDOT fibers is anisotropic, but not as anisotropic as one may expect. Indeed, these results challenge the usual expectation that thermal conduction along the backbone largely exceeds those along the lamellar and pi-pi direction, showing that anisotropy can be tuned by controlling the nanofiber aspect ratio. image, Funding Agencies|European Commission [GA-955837]; MCIN/AEI [PID2020-119777GB-I00]; Severo Ochoa Centres of Excellence Program [CEX2019-000917-S]; Generalitat de Catalunya [2017 SGR 1506]

This study provides a methodology for exploring the microstructural and mechanical properties of the Haynes (R) 282 (R) alloy produced via the Powder Bed Fusion-Electron Beam (PBF-EB) process. Employing 2D Electron Backscatter Diffraction (EBSD) data, we have successfully generated 3D representations of columnar microstructures using the Representative Volume Element (RVE) method. This methodology allowed for the validation of elastic properties through Crystal Elasticity Finite Element (CEFE) computational homogenization, revealing critical insights into the material behavior. This study highlights the importance of accurately representing the grain morphology and crystallographic texture of the material. Our findings demonstrate that created virtual models can predict directional elastic properties with a high level of accuracy, showing a maximum error of only similar to 5% compared to the experimental results. This precision underscores the potential of our approach for predictive modeling in Additive Manufacturing (AM), specifically for materials with complex, non-homogeneous microstructures. It can be concluded that the results uncover the intricate link between microstructural features and mechanical properties, underscoring both the challenges encountered and the critical need for the accurate representation of grain data, as well as the significance of achieving a balance in EBSD area selection, including the presence of anomalies in strongly textured microstructures., Funding Agencies|Knowledge Foundation [20200050 PODFAM]

Poly(styrene-methyl methacrylate-acrylic acid) photonic crystals (PCs), with five different sizes (170, 190, 210, 230 and 250 nm), were applied onto three plain fabrics, namely polyamide, polyester and cotton. The PC-coated fabrics were analyzed using scanning electronic microscopy and two UV/Vis reflectance spectrophotometric techniques (integrating sphere and scatterometry) to evaluate the PCs' self-assembly along with the obtained spectral and colors characteristics. Results showed that surface roughness of the fabrics had a major influence on the color produced by PCs. Polyamide-coated fabrics were the only samples having an iridescent effect, producing more vivid and brilliant colors than polyester and cotton samples. It was observed that as the angle of incident light increases, a hypsochromic shift in the reflection peak occurs along with the formation of new reflection peaks. Furthermore, color behavior simulations were performed with an illuminant A light source on polyamide samples. The illuminant A simulation showed greener and yellower structural colors than those illuminated with D50. The polyester and cotton samples were analyzed using scatterometry to check for iridescence, which was unseen upon ocular inspection and then proven to be present in these samples. This work allowed a better comprehension of how structural colors and their iridescence are affected by the textile substrate morphology and fiber type., Funding Agencies|FEDER [UID/CTM/00264/2020]; National Funds through Fundao para a Cincia e Tecnologia (FCT) [2022-03370]; Swedish Research Council [P2021-00040]; Swedish Energy Agency [.9220423]; Swedish Armed Forces research program AT [SFRH/BD/145269/2019]; FCT, MCTES, FSE

In this work we present a systematic set of measurements carried out by muon spin rotation/relaxation (mu+SR) and neutron powder diffraction (NPD) on the solid solution NaxCa1-xCr2O4. This study investigates Na-ion dynamics in the quasi-1D (Q1D) diffusion channels created by the honeycomb-like arrangement of CrO6 octahedra, in the presence of defects introduced by Ca substitution. With increasing Ca content, the size of the diffusion channels is enlarged; however, this effect does not enhance the Na ion mobility. Instead the overall diffusivity is hampered by the local defects and the Na hopping probability is lowered. The diffusion mechanism in NaxCa1-xCr2O4 is proposed to be interstitial and the activation energy as well as diffusion coefficient are determined for all the members of the solid solution., Funding Agencies|Stiftelsen fr Strategisk Forskning [2019B0420, 2019A0330, 2019A0328]; Science and Technology Facilities Council (STFC); RIKEN-RAL facilities - Swedish Foundation for Strategic Research (SSF) within the Swedish national graduate school in neutron scattering (SwedNess) [2021-06157, 2017-05078]; Swedish Research Council VR; Carl Tryggers Foundation for Scientific Research [CTS-18:272, SNP21-0004]; Japan Society for the Promotion Science (JSPS) KAKENHI [JP18H01863, JP20K21149, JP23H01840]; Swedish Research Council (VR) through the Postdoc International grant [2022-06217]; Foundation Blanceflor 2023 fellow scholarship [2017-05078]; Swedish Research Council (VR) through a Starting Grant; Knut and Alice Wallenberg Foundation [2021.0150]

Integrating interfacial molecular nanolayers (MNL) with inorganic nanolayers is of interest for understanding processing-structure/chemistry correlations in hybrid nanolaminates. Here, we report the synthesis of Co/biphenyldithiol (BPDT)/Co nanolayer sandwiches by metal sputter-deposition and molecular sublimation. The density and surface roughness of the Co layers deposited on the native oxide are invariant with the Ar pressure pAr during deposition. In contrast, the Co layer roughness rCo deposited on top of the BPDT MNL increases with pAr, and correlates with a higher degree of Co oxidation. Increased roughening is attributed to MNL-accentuated self-shadowing of low mobility Co atoms at high pAr, which consequently increases Co oxidation. These results indicating MNL-induced effects on the morphology and chemistry of the inorganic layers should be of importance for tailoring nanolayered hybrid interfaces and laminates. Co/biphenyldithiol (BPDT)/Co nanolayer sandwiches are synthesized by metal sputter deposition and molecular sublimation. These results indicate molecular-nanolayer-induced effects on the morphology and chemistry, of interest for hybrid nanolaminates., Funding Agencies|National Science Foundation [CMMI 2135725]; US National Science Foundation [2009 00971]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials Grant SFO-Mat-LiU [KAW-2020.0196, KAW-2019.0290]; Knut and Alice Wallenberg foundation through the Wallenberg Academy Fellows Grant [2021-03826]; Swedish Research Council through the VR

Heat is an inexhaustible source of energy, and it can be exploited by thermoelectronics to produce electrical power or electrical responses. The search for a low-cost thermoelectric material that could achieve high efficiencies and can also be straightforwardly scalable has turned significant attention to the halide perovskite family. Here, we report the thermal voltage response of bismuth-based perovskite derivates and suggest a path to increase the electrical conductivity by applying chalcogenide doping. The films were produced by drop-casting or spin coating, and sulfur was introduced in the precursor solution using bismuth triethylxanthate. The physical-chemical analysis confirms the substitution. The sulfur introduction caused resistivity reduction by 2 orders of magnitude, and the thermal voltage exceeded 40 mV K-1 near 300 K in doped and undoped bismuth-based perovskite derivates. X-ray diffraction, Raman spectroscopy, and grazing-incidence wide-angle X-ray scattering were employed to confirm the structure. X-ray photoelectron spectroscopy, elemental analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were employed to study the composition and morphology of the produced thin films. UV-visible absorbance, photoluminescence, inverse photoemission, and ultraviolet photoelectron spectroscopies have been used to investigate the energy band gap., Funding Agencies|H2020 Marie Sklodowska-Curie Actions [56338]; European Union [IESR3193231]; Royal Society International Exchanges Award; Fondo di Ateneo Quota Competitiva [2023-ATEQC-0078]; Innovate UK; National Recovery and Resilience Plan (NRRP) Mission 4 Component 2 Investment Line 1.5 [UF140372, URF/R/201013]

Nitrogen catenation under high pressure leads to the formation of polynitrogen compounds with potentially unique properties. The exploration of the entire spectrum of poly- and oligo-nitrogen moieties is still in its earliest stages. Here, we report on four novel scandium nitrides, Sc2N6, Sc2N8, ScN5, and Sc4N3, synthesized by direct reaction between yttrium and nitrogen at 78-125 GPa and 2500 K in laser-heated diamond anvil cells. High-pressure synchrotron single-crystal X-ray diffraction reveals that in the crystal structures of the nitrogen-rich Sc2N6, Sc2N8, and ScN5 phases nitrogen is catenated forming previously unknown N-6(6)- and N-8(6)- units and infinity 2(N-5(3-)) anionic corrugated 2D-polynitrogen layers consisting of fused N-12 rings. Density functional theory calculations, confirming the dynamical stability of the synthesized compounds, show that Sc2N6 and Sc2N8 possess an anion-driven metallicity, while ScN5 is an indirect semiconductor. Sc2N6, Sc2N8, and ScN5 solids are promising high-energy-density materials with calculated volumetric energy density, detonation velocity, and detonation pressure higher than those of TNT., Funding Agencies|National Science Foundation - Earth Sciences [EAR - 1634415]; DOE Office of Science by Argonne National Laboratory [DE-AC02-06CH11357]; UKRI Future Leaders Fellowship [MR/V025724/1]; Deutsche Forschungsgemeinschaft (DFG) [DU 945/15-1, LA 4916/1-1, DU 954-11/1, DU 393-9/2, DU 393-13/1]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoeping University [2009 00971]; Open Access Publishing Fund of the University of Bayreuth; Projekt DEAL

Wurtzite TmAlN (T-m = transition metal) themselves are of interest as semiconductors with tunable band gap, insulating motifs to superconductors, and piezoelectric crystals. Characterization of wurtzite TmAlN is challenging because of the difficulty to synthesize them as single-phase solid solution and such thermodynamic, elastic properties, and high temperature behavior of wurtzite Ti1-xAlxN is unknown. Here, we investigated the high temperature decomposition behavior of wurtzite Ti1-xAlxN films using experimental methods combined with first-principles calculations. We have developed a method to grow single-phase metastable wurtzite Ti1-xAlxN (x = 0.65, 0.75, 085, and 0.95) solid-solution films by cathodic arc deposition using low duty-cycle pulsed substrate-bias voltage. We report the full elasticity tensor for wurtzite Ti1-xAlxN as a function of Al content and predict a phase diagram including a miscibility gap and spinodals for both cubic and wurtzite Ti1-xAlxN. Complementary high-resolution scanning transmission electron microscopy and chemical mapping demonstrate decomposition of the films after high temperature annealing (950 degrees C), which resulted in nanoscale chemical compositional modulations containing Ti-rich and Al-rich regions with coherent or semicoherent interfaces. This spinodal decomposition of the wurtzite film causes age hardening of 1-2 GPa., Funding Agencies|Swedish National Infras-tructure for Computing (SNIC) - Swedish Research Council [VR-2015-04630]; Swedish National Infrastructure for Computing (SNIC); National Academic Infrastructure for Supercomputing in Sweden (NAISS); Swedish Research Council [VR-2015-04630]; VINNOVA (FunMat-II project) [2022-03071]; Swedish Research Council (VR) [2017-03813, 2017-06701, 2021-04426, 2021-00357, 2019-00191]; Swedish government strategic research area [AFM-SFO MatLiU (2009-00971)]; Knut and Alice Wallenberg Foundation [KAW-2018.0194]

In this study, a cast synthesis approach was used to create flexible nanocomposite films made of polyacrylamide (PAM), chitosan (Cs), and zinc ferrite nanoparticles (ZnFe2O4 NPs). XRD analysis was used to examine the composite structure. They demonstrated the effective interaction between ZnFe2O4 NPs and PAM/Cs blend. As the concentration of nanomaterial in the host polymer matrix grew, it was observed that the PAM/Cs matrix's direct and indirect energy band gaps decreased while its absorbance of ultraviolet-visible radiations increased. The nanocomposite's AC conductivity was significantly higher than that of the blend, and 2.5 wt percent of the nanocomposite showed the highest electrical conductivity. It was observed that as frequency raised, the epsilon ' and epsilon '' declined though the concentration of nanoparticles enhanced these characteristics. Because of the high dielectric permittivity of ZnFe2O4, the values of epsilon ' and epsilon '' raised as ZnFe2O4 were higher. The outcome of the vibrating sample magnetometer (VSM) demonstrated the ferromagnetic property of the produced nanocomposites. Furthermore, the VSM study shows that as the nanoparticles content increases, the PAM/Cs/ZnFe2O4 nanocomposites' Ms, Hc, and Mr also increase. These PAM/Cs/ZnFe2O4 films were shown by the experimental results to be promising candidates for bandgap-regulated materials, electromagnetic interference shielders, frequency tunable nanodielectric, and flexible dielectric substrates for future microelectronic, optoelectronic technologies, and capacitive energy storage., Funding Agencies|Deanship of Scientific Research at Imam Mohammad Ibn Saud Islamic University (IMSIU) [IMSIU-RP23023]

Organic semiconductors are increasingly being decorated with hydrophilic solubilising chains to create materials that can function as mixed ionic-electronic conductors, which are promising candidates for interfacing biological systems with organic electronics. While numerous organic semiconductors, including p- and n-type materials, small molecules and polymers, have been successfully tailored to encompass mixed conduction properties, common to all these systems is that they have been semicrystalline materials. Here, we explore how side chain engineering in the nano-crystalline indacenodithiophene-co-benzothiadiazole (IDTBT) polymer can be used to instil ionic transport properties and how this in turn influences the electronic transport properties. This allows us to ultimately assess the mixed ionic-electronic transport properties of these new IDTBT polymers using the organic electrochemical transistor as the testing platform. Using a complementary experimental and computational approach, we find that polar IDTBT derivatives can be infiltrated by water and solvated ions, they can be electrochemically doped efficiently in aqueous electrolyte with fast doping kinetics, and upon aqueous swelling there is no deterioration of the close interchain contacts that are vital for efficient charge transport in the IDTBT system. Despite these promising attributes, mixed ionic-electronic charge transport properties are surprisingly poor in all the polar IDTBT derivatives. Albeit a "negative" result, this finding clearly contradicts established side chain engineering rules for mixed ionic-electronic conductors, which motivated our continued investigation of this system. We eventually find this anomalous behaviour to be caused by increasing energetic disorder in the polymers with increasing polar side chain content. We have investigated computationally how the polar side chain motifs contribute to this detrimental energetic inhomogeneity and ultimately use the learnings to propose, Funding Agencies|European Commission [964677, 2.5020.11]; European Commission Horizon 2020 Future and Emerging Technologies (FET) [1117545]; Walloon Region; National Science Foundation [DMR-1751308]; NSF [DE-AC02-06CH11357]; DOE Office of Science by Argonne National Laboratory

Nanostructured materials and nanocomposites have shown great promise for improving the efficiency of thermoelectric materials. Herein, Fe nanoparticles were imbedded into a CrN matrix by combining two physical vapor deposition approaches, namely, high-power impulse magnetron sputtering and a nanoparticle gun. The combination of these techniques allowed the formation of nanocomposites in which the Fe nanoparticles remained intact without intermixing with the matrix. The electrical and thermal transport properties of the nanocomposites were investigated and compared to those of a monolithic CrN film. The measured thermoelectric properties revealed an increase in the Seebeck coefficient, with a decrease of hall carrier concentration and an increase of the electron mobility, which could be explained by energy filtering by internal phases created at the NP/matrix interface. The thermal conductivity of the final nanocomposite was reduced from 4.8 W m(-1) K-1 to a minimum of 3.0 W m(-1) K-1. This study shows prospects for the nanocomposite synthesis process using nanoparticles and its use in improving the thermoelectric properties of coatings., Funding Agencies|Vetenskapsr?det [2009 00971]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2021-03826]; Swedish Research Council (VR) [KAW 2016.0346]; Knut and Alice Wallenberg Foundation; Kempe Foundation [2019-00191]; Swedish Research Council VR-RFI [RIF14-0053]; Swedish Foundation for Strategic Research

The demonstration of an efficient nanostructure that provides acceptable photoelectrochemical water splitting properties using the sun visible radiation is an appealing issue. In this connection, a new ternary nanocomposite of Ag2S/MoS2/ZnO photoanode is subsequently fabricated via hydrothermal, solvothermal and SILAR methods. Different properties of the nanocomposite are characterized by XRD, SEM, EDX, XPS, UV-Vis-IR spectroscopy and electrochemical techniques. The post-grown annealed 8-Ag2S/MoS2/ZnO photoanode exhibits a good performance with a photocurrent density of 2 mA/cm2 at a bias potential 1.23 V vs. RHE. The photocurrent of the post-grown annealed 8-Ag2S/MoS2/ZnO photoanode is 71.42 times, 40 times and 2 times higher compares to the pure ZnO, post-grown annealed MoS2/ZnO, and post-grown annealed 8-Ag2S/ZnO photoanodes, respectively. The enhanced PEC performance may originate from the combination of different effects such as the expansion of light absorption and energy band alignment (type II heterostructures), [SO4] acted as a charge -transfer medium, and electrode-electrolyte interface kinetic reactions., Funding Agencies|Department of Science and Technology (ITN) , Linkoping University, Sweden; International Science Program (ISP) as well as (SIDA)

Time-resolved ion mass spectrometry is used to analyze the type and the energy of metal-ion fluxes during hybrid high-power impulse/direct-current magnetron co-sputtering (HiPIMS/DCMS) in Ar. The study focuses on the effect of HiPIMS plasma plumes on the cross-ionization of the material flux sputtered from the DCMS source. Al, Si, Ti, and Hf elemental targets are used to investigate the effect of the metal's first ionization potential IPMe1 and mass on the extent of cross-ionization. It is demonstrated that the interaction with HiPIMS plasma results in the significant ionization of the material flux sputtered from the DCMS source. Experiments conducted with elements of similar mass but having different IPMe1 values, Si and Al (Si-HiPIMS/Al-DCMS and Al-HiPIMS/Si-DCMS) reveal that the ionization of the DCMS flux is favored if the sputtered element has lower ionization potential than the one operating in the HiPIMS mode. If elements having similar IPMe1 are used on both sources, the metal mass becomes a decisive parameter as evidenced by experiments involving Ti and Hf (Ti-HiPIMS/Hf-DCMS and Hf-HiPIMS/Ti-DCMS). In such a case, Ti+ fluxes during Hf-HiPIMS/Ti-DCMS may even exceed Hf+ fluxes from the HiPIMS cathode and are much stronger than Hf+ fluxes during Ti-HiPIMS/Hf-DCMS. The latter effect can be explained by the fact that heavier Hf+ ions require longer transit time from the ionization zone to the substrate, which effectively increases the probability of interaction between the Hf-HiPIMS plasma plume and the Ti-DCMS flux, thereby leading to higher Ti ionization. Thus, the common notion of low ionization levels associated with DCMS has to be revised if DCMS is used together with highly ionized plasmas such as HiPIMS operating at higher peak target currents. These results are particularly important for the film growth in the hybrid configuration with substrate bias pulses synchronized to specific ion types., Funding Agencies|Swedish Research Council VR [2018-03957]; Swedish Energy Agency [51201-1]; Aforsk Foundation [22-4]; Knut and Alice Wallenberg Foundation Scholar [KAW2019.0290]; Olle Enqvist Foundation [222-0053]; Carl Tryggers Stiftelse [CTS 20:150]; Polish National Agency for Academic Exchange upon the NAWA Bekker [BPN/BEK/2021/1/00366/U/00001]; Wallenberg Initiative Materials Science for Sustainability (WISE) - Knut and Alice Wallenberg Foundation; Slovak Research and Development Agency [APVV-21-0042]; Operational Program Integrated Infrastructure for the project: Advancing University Capacity and Competence in Research, Development and Innovation (ACCORD); European Regional Development Fund

Transforming recyclable materials into a suitable product is an important area of research nowadays. This report demonstrates that carbon material derived from waste printer cartridges can be exploited to fabricate electrochemical cells-particularly supercapacitors (SCs). SCs are electrochemical energy storage devices currently attracting much attention in the research community due to their salient features, such as cost-effectiveness, extended cycle stability, and durability. Here, we report the results of thoroughly examining the effects of acidic, basic, and neutral aqueous electrolytes on printer waste carbon electrode material in SC efficiency. In our work, the waste carbon collected from used printer cartridges shows a specific capacitance of 178.4 F/g with energy and power density of 24.77 Wh/kg and 999.68 W/kg, respectively, at 0.5 A/g current density in acidic (1 M H2SO4) electrolyte medium. Moreover, it exhibited very promising capacitance of 135.04 F/g and 87.04 F/g in basic (1 M LiOH) and neutral (1 M NaCl) electrolyte medium, respectively, at 0.8 A/g current density with considerably better cycle stability. In an acidic medium, printer waste carbon drives a DC motor for 1 min with a three-cell series arrangement. The properties of that waste carbon (extracted from the cartridges) are similar to high-rate activated carbon available commercially., Funding Agencies|University Grant Commission (UGC); National Institute of Technology Karnataka (NITK), Surathkal; Central Research Facility (CRF) at NITK; Ministry of Education (MoE)

Research on perovskites has grown exponentially in the past decade due to the potential of methyl ammonium lead iodide in photovoltaics. Although these devices have achieved remarkable and competitive power conversion efficiency, concerns have been raised regarding the toxicity of lead and its impact on scaling up the technology. Eliminating lead while conserving the performance of photovoltaic devices is a great challenge. To achieve this goal, the research has been expanded to thousands of compounds with similar or loosely related crystal structures and compositions. Some materials are "re-discovered", and some are yet unexplored, but predictions suggest that their potential applications may go beyond photovoltaics, for example, spintronics, photodetection, photocatalysis, and many other areas. This short review aims to present the classification, some current mapping strategies, and advances of lead-free halide double perovskites, their derivatives, lead-free perovskitoid, and low-dimensional related crystals., Funding Agencies|Knut and Alice Wallenberg Foundation

A series of c-TiAlN/ h-Cr2N multilayer films with modulation periods Lambda of 10, 20 and 30 nm and thickness ratios (Cr2N thickness /Lambda) of 25%, 50% and 75% were prepared by dc magnetron sputtering on the Si substrate. The microstructures were characterized by scanning electron microscopy, x-ray diffraction, and the mechanical properties were measured by curvature measurement method and nanoindentation. With the Cr2N ratio increasing from 25% to 75%, the orientation of Cr2N layers changed from a randomly orientation to a 0001 preferential orientation, while inversely, the c-TiAlN layer changed from a 001 preferential orientation to a 111 preferential orientation or a randomly orientation. In the meantime, and regardless of the modulation period, the lattice parameter of c-TiAlN decreased from 4.16 angstrom to 4.12 angstrom and was explained by an increase of tensile stress between + 0.2 and + 1.3 GPa when the increase of Cr2N% in the modulation. With the increase of Cr2N ratio, the morphology of the film changed and led to surface with apparent porosity and large grain sizes of 100 x 300 nm. The film with 25% Cr2N ratio and modulation period of 20 nm exhibited the highest hardness reaching 22 +/- 1.3 GPa and reduced Young's modulus of 253 +/- 6 GPa., Funding Agencies|Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Knut and Alice Wallenberg foundation through the Wallenberg Academy Fellows program [KAW-2020.0196]; Swedish Research Council (VR) [2021-03826]; Swedish Energy Agency [52740-1]; National Natural Science Foundation of China [52272065]; National Major Science and Technology Projects of China [Y2022-III-0004-0013, NP2022424]; National Major Science and Tech-nology Projects of China [202106830068]; Fundamental Research Fund for the Central Universities; China Scholarship Council (CSC) [NWK20220113]

The stabilization of grain boundaries and surfaces of the perovskite layer is critical to extend the durability of perovskite solar cells. Here we introduced a sulfonium-based molecule, dimethylphenethylsulfonium iodide (DMPESI), for the post-deposition treatment of formamidinium lead iodide perovskite films. The treated films show improved stability upon light soaking and remains in the black alpha phase after two years ageing under ambient condition without encapsulation. The DMPESI-treated perovskite solar cells show less than 1% performance loss after more than 4,500 h at maximum power point tracking, yielding a theoretical T80 of over nine years under continuous 1-sun illumination. The solar cells also display less than 5% power conversion efficiency drops under various ageing conditions, including 100 thermal cycles between 25 degrees C and 85 degrees C and an 1,050-h damp heat test. Suo et al. show that sulfonium-based molecules afford formamidinium lead iodide perovskites protection against environmental stress factors, improved phase stability and solar cells retaining efficiency over 4,500-h operational stability tests., Funding Agencies|Swiss National Science Foundation; European Union's Horizon 2020 research and innovation programme; Horizon Europe framework programme for research and innovation; Project Ricerca@CNR PHOTOCAT; Italian Ministry of Environment and Energy Security; European Union's Horizon Europe research and innovation programme; German Federal Environmental Foundation (DBU); Engineering and Physical Sciences Research Council (EPSRC) Doctoral Prize Fellowship [200020_185041, 101082176-VALHALLA]; Winton Sustainability Fund Studentship [200021_213073]; Oppenheimer Research Fellowship [764047]; Schmidt Science Fellowship [101084124-DIAMOND]; Research Fellowship at Murray Edwards College [CUP B93C21000060006]; Royal Society and Tata Group [CSEAA_00011]; EPSRC; European Research Council; Biotechnology and Biological Sciences Research Council (BBSRC); University of Warwick; Uppsala University; [UF150033]; [EP/R023980/1]; [756962]; [EP/T015063/1]; [EP/R029946/1]

One of the key characteristics of mesoporous films, making them attractive in many applications, is the surface enhancement gained by the porosity. Today, this attribute is rarely presented for particle-based mesoporous films. This work shows that krypton physisorption can be used to determine the available surface area of particle-based silica films synthesized by the direct growth (DiG) method. The surface area per substrate area of the films was measured to be 50-170 m(2)/m(2) and the surface area per film volume was 310-490 m(2)/cm(3) when the film thickness was varied between 100 and 520 nm. For comparison, a 105 nm thick film synthesized using dip-coating was used, as this technique renders more smooth films. The corresponding values for the dip-coated film was 90 m(2)/m(2) and 880 m(2)/cm(3), showing a higher surface area per film volume for the continuous film. The method is hence suitable for the characterization of mesoporous films synthesized with various techniques and can be used for the optimization of catalysts, drug delivery systems, and sensors., Funding Agencies|Swedish Agency for Innovation Systems (Vinnova) [2016-05156]; Swedish Government Strategic Research Area in Materials Science on Functional Materials [2009-00971]; Swedish Research Council [2015-00624, 2021-04427]

c-TiAlN/h-Cr2N multilayer thin films, with modulation period lambda of 10 nm, 20 nm, and 30 nm and different Cr2N/lambda thickness ratios (25 %, 50 % and 75 %), were deposited on c-plane sapphire using reactive DC magnetron sputtering. All multilayers exhibited preferred orientation [Cr2N(0001)/ TiAlN(111)](x), regardless of the modulation period and thickness ratios. X-ray diffraction f-scans revealed an influence of the Cr2N layer thickness on the overall orientation quality of the multilayer, where the thicker the Cr2N layer the higher orientation quality. Atomically resolved high-angle annular dark-field scanning transmission electron microscopy revealed well defined and homogeneous atom stacking in the Cr2N layers. In contrast, the cubic TiAlN layer was found to be composed of coherent cubic AlN-rich and TiN-rich regions. Additionally, the TiAlN layers were found with a higher density of grain boundaries compared to the Cr2N layers. Mechanical properties evaluation revealed that the film with a 20 nm period and 75 % Cr2N thickness ratio exhibited the highest hardness of 27.11 +/- 0.72 GPa and an reduced elastic modulus of 349.1 +/- 6.84 GPa. The hardness increased as the thickness of Cr2N increased, until reaching 10 nm, after which it remained at a high level (similar to 25 GPa)., Funding Agencies|Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Knut and Alice Wallenberg foundation through the Wallenberg Academy Fellows program [KAW-2020.0196]; Swedish Research Council (VR) [2021-03826]; Swedish Energy Agency [52740-1]; National Natural Science Foundation of China [52272065]; National Major Science and Technology Projects of China [2017-IV-00-05-0042]; Fundamental Research Fund for the Central Universities [NP2022424]; China Scholarship Council (CSC) [202106830068]; Swedish Foundation for Strategic Research (SSF); Swedish National Infrastructure in Advanced Electron Microscopy [2021-00171, RIF21-0026]

Conducting cellulose composites are promising sustainable functional materials that have found application in energy devices, sensing and water purification. Herein, conducting aerogels are fabricated based on nanofibrillated cellulose and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, using the ice templating technique, and their bulk morphology is characterized with X-ray microtomography. The freezing method (-20 degrees C in a freezer vs liquid nitrogen) does not impact the mean porosity of the aerogels but the liquid-N2 aerogels have smaller pores. The integration of carbon fibers as addressing electrodes prior to freezing results in increased mean porosity and pore size in the liquid-N2 aerogels signifying that the carbon fibers alter the morphology of the aerogels when the freezing is fast. Spatially resolved porosity and pore size distributions also reveal that the liquid-N2 aerogels are more inhomogeneous. Independent of the freezing method, the aerogels have similar electrochemical properties. For aerogels without carbon fibers, freezer-aerogels have higher compression modulus and are less stable under cycling compression fatigue test. This can be explained by higher porosity with larger pores in the center of liquid-N2 aerogels and thinner pore walls. This work demonstrates that micro-CT is a powerful tool for characterizing the morphology of aerogels in a non-destructive and spatially resolved manner. Conducting aerogels based on nanofibrillated cellulose and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate are fabricated with the ice templating technique and their bulk morphology is characterized in a spatially resolved manner with X-ray microtomography. The effect of the freezing temperature and the integration of carbon fibers electrodes prior to freezing on the morphology, mechanical, and electrochemical properties is examined., Funding Agencies|Wallenberg Wood Science Center [KAW 2018.0452]; European Unions Horizon 2020 research and innovation programme (FET-OPEN-HyPhOE) [800926]; Swedish Research Council [VR-2017-04910, VR 2022-03507]; Swedish Foundation for Strategic Research [ID17-0097, FFL-18-0101]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University [2009-00971]

Aluminum nitride (AlN) is an important material for semiconductor devices, such as ultraviolet light emitting diodes (LEDs) or high-electron-mobility transistors (HEMTs). One emerging approach to deposit very thin, and highly conformal AlN films is atomic layer deposition (ALD), most commonly by using trimethyl aluminum (TMA) and ammonia. Despite TMA being one of the most common ALD precursors, its surface chemistry in ALD of AlN is poorly understood. By quantum chemical modeling, we have investigated the adsorption and decomposition of TMA on an AlN surface. We have found two competing decomposition pathways, either ligand exchange by protonation of the methyl groups in TMA by a surface amino group, or reductive elimination of the methyl groups as ethane. Reductive elimination is shown to be the dominating reaction step if a TMA molecule adsorbs far from any previously adsorbed molecule. Ligand exchange is preferred if it adsorbs close to an already adsorbed molecule. By comparing the obtained surfaces after decomposition, we find that the saturation coverage is dependent on the preferred pathways with a third of a monolayer saturation for reductive elimination and a full for ligand exchange. The relative low diffusion rate compared to decomposition rate of TMA will cause the molecules to be far apart after adsorption, and we conclude that the dominating decomposition path is reductive elimination. Two different pathways for decomposition of adsorbed trimethyl aluminum in the ALD of AlN have been investigated by computation chemistry. The two pathways give different saturation coverage and thus growth per cycle., Funding Agencies|Swedish foundation for Strategic Research through the project "Time-resolved low temperature CVD for IIInitrides" [SSF-RMA 15-0018]; Swedish Research Council (VR)

Green and scalable materials are essential to fulfill the need of electrification for transitioning into a fossil-fuels free society, and sustainability is a requirement for all new technologies. Rechargeable batteries are one of the most important elements for electrification, enabling the transition to mobile electronics, electrical vehicles and grid storage. We here report synthesis and characterization of polyelectrolyte complexes of alginate and chitosan, both biopolymers deriving from the sea, for transport of zinc ions in hydrogel electrolytes. We have used vibrational spectroscopy, thermal measurements and microscopy, as well as transport measurements with ohmic or blocking contacts. The transference number for zinc ions is close to 1, the conductivity is approximate to 10 mS/cm, with stability at Zn interfaces seen through 7000 cycles in symmetric zinc//zinc cell. A zinc ion aqueous electrolyte was prepared from blends of chitosan and alginate, by using a simple and scalable route. These green zinc ion electrolytes exhibit a stability window up to 2 V, a zinc ion transference number close to 1, and electrochemical cyclability over 7000 cycles at interfaces to zinc. This biologically derived polyelectrolyte complex offers many possibilities for optimizing transport and stability at electrode interfaces.image, Funding Agencies|Knut and Alice Wallenberg Foundation [2018.0058]

Inherent brittleness, which easily leads to crack formation and propagation during use, is a serious problem for protective ceramic thin-film applications. Superlattice architectures, with alternating nm-thick layers of typically softer/stiffer materials, have been proven powerful method to improve the mechanical performance of, e.g., cubic transition metal nitride ceramics. Using high-throughput first-principles calculations, we propose that superlattice structures hold promise also for enhancing mechanical properties and fracture resistance of transition metal diborides with two competing hexagonal phases, a and ?. We study 264 possible combinations of a/a, a/? or co/co MB2 (where M = Al or group 3-6 transition metal) diboride superlattices. Based on energetic stability considerations, together with restrictions for lattice and shear modulus mismatch (?a < 4%, ?G > 40 GPa), we select 33 superlattice systems for further investigations. The identified systems are analysed in terms of mechanical stability and elastic constants, C-ij, where the latter provide indication of in-plane vs. out of-plane strength ( C-11, C-33 ) and ductility ( C-13 - C-44, C-12 - C-66 ). The superlattice ability to resist brittle cleavage along interfaces is estimated by Griffiths formula for fracture toughness. The a/a-type TiB2 /MB2 (M = Mo, W), HfB2/WB2, VB2/MB2 (M = Cr, Mo), NbB2/MB2 (M = Mo, W), and a/?-type AlB2/MB2 (M = Nb, Ta, Mo, W), are suggested as the most promising candidates providing atomic-scale basis for enhanced toughness and resistance to crack growth., Funding Agencies|Slovak Research and Development Agency [APVV-21-0042]; Scientific Grant Agency [VR-2021-04426]; Operational Program Integrated Infrastructure [2022-06725]; Hertha Firnberg fellowship by Austrian Science Fund, FWF; Swedish Research Council [2022-03071, VEGA 1/0296/22]; Competence Center Functional Nanoscale Materials (FunMat-II, Vinnova) [T30801]; Vienna Scientific Cluster (VSC) in Austria; [ITMS 313011AUH4]; [2018-05973]

Realizing stress-free inorganic epitaxial films on weakly bonding substrates is of importance for applications that require film transfer onto surfaces that do not seed epitaxy. Film-substrate bonding is usually weakened by harnessing natural van der Waals layers (e.g., graphene) on substrate surfaces, but this is difficult to achieve in non-layered materials. Here, we demonstrate van der Waals epitaxy of stress-free films of a non-layered material VO2 on mica. The films exhibit out-of-plane 010 texture with three inplane orientations inherited from the crystallographic domains of the substrate. The lattice parameters are invariant with film thickness, indicating weak film-substrate bonding and complete interfacial stress relaxation. The out-of-plane domain size scales monotonically with film thickness, but the in-plane domain size exhibits a minimum, indicating that the nucleation of large in-plane domains supports subsequent island growth. Complementary ab initio investigations suggest that VO2 nucleation and van der Waals epitaxy involves subtle polarization effects around, and the active participation of, surface potassium atoms on the mica surface. The VO2 films show a narrow domain-size-sensitive electrical-conductiv ity-temperature hysteresis. These results offer promise for tuning the properties of stress-free van der Waals epitaxial films of non-layered materials such as VO2 through microstructure control (C) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)., Funding Agencies|Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoeping University [2009 00971]; Swedish Research Council [2021-03826, 2021-04426]; Swedish Energy Agency [46519-1]; Knut and Alice Wallenberg foundation through the Wallenberg Academy Fellows program [KAW-2020.0196]; Linkoeping Electron Microscopy Laboratory; Swedish Foundation for Strategic Research (SSF) [RIF 14-0074]; French government program "Investissements dAvenir" [ANR-18-EURE-0010, ANR-11-LABX-0017-01]; US National Science Foundation [CMMI 2135725]

Questo lavoro si concentra sulla possibile applicazione di nanoparticelle d'oro su tessuti di cotone flessibili come substrati sensibili all'acetone e all'etanolo mediante misurazioni di impedenza. Nello specifico, nanoparticelle d'oro (NP Au) funzionalizzate con citrato e polivinilpirrolidone (PVP) sono state sintetizzate utilizzando procedure verdi e consolidate e depositate su tessuto di cotone. Una caratterizzazione strutturale e morfologica completa è stata condotta utilizzando la spettroscopia UV-VIS e infrarossa a trasformata di Fourier (FT-IR), la microscopia a forza atomica (AFM) e la microscopia elettronica a scansione (SEM). Una caratterizzazione dielettrica dettagliata del substrato vuoto ha rivelato effetti di polarizzazione interfacciale legati sia alle NP Au che alla loro specifica funzionalizzazione superficiale. Ad esempio, rivestendo interamente il tessuto di cotone (ovvero creando una matrice più isolante), è stato riscontrato che il PVP aumenta la resistenza del campione, ovvero diminuisce l'interconnessione elettrica delle NP Au rispetto al campione funzionalizzato con citrato. Tuttavia, è stato osservato che la funzionalizzazione del citrato ha fornito una distribuzione uniforme delle NP Au, che ha ridotto la loro spaziatura e, quindi, facilitato il trasporto degli elettroni. Per quanto riguarda il rilevamento dei composti organici volatili (COV), le misurazioni della spettroscopia di impedenza elettrochimica (EIS) hanno mostrato che il legame idrogeno e la risultante impedenza di migrazione protonica sono fondamentali per distinguere l'etanolo dall'acetone., This work focuses on the possible application of gold nanoparticles on flexible cotton fabric as acetone- and ethanol-sensitive substrates by means of impedance measurements. Specifically, citrate- and polyvinylpyrrolidone (PVP)-functionalized gold nanoparticles (Au NPs) were synthesized using green and well-established procedures and deposited on cotton fabric. A complete structural and morphological characterization was conducted using UV-VIS and Fourier transform infrared (FT-IR) spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM). A detailed dielectric characterization of the blank substrate revealed interfacial polarization effects related to both Au NPs and their specific surface functionalization. For instance, by entirely coating the cotton fabric (i.e., by creating a more insulating matrix), PVP was found to increase the sample resistance, i.e., to decrease the electrical interconnection of Au NPs with respect to citrate functionalized sample. However, it was observed that citrate functionalization provided a uniform distribution of Au NPs, which reduced their spacing and, therefore, facilitated electron transport. Regarding the detection of volatile organic compounds (VOCs), electrochemical impedance spectroscopy (EIS) measurements showed that hydrogen bonding and the resulting proton migration impedance are instrumental in distinguishing ethanol and acetone. Such findings can pave the way for the development of VOC sensors integrated into personal protective equipment and wearable telemedicine devices. This approach may be crucial for early disease diagnosis based on nanomaterials to attain low-cost/low-end and easy-to-use detectors of breath volatiles as disease markers., Funding: The authors thanks T. De Caro, A. Brotzu, L. Zortea, and L. Cerri for their technical support in Raman, SEM, and AFM measurements.

Multicomponent or high-entropy oxide films are of interest due to their remarkable structure and properties. Here, energetic ion irradiation is utilized for controlling the phase formation and structure of AlCrNbTi oxide at growth temperature of 500 degrees C. The ion acceleration is achieved by using a high-power impulse magnetron sputtering (HiPIMS) discharge, accompanied by a 10 & mu;s-long synchronized substrate bias (Usync), to minimize the surface charging effect and accelerate early-arriving ions, mainly Al+, O+, Ar2+, and Al2+. By increasing the magnitude of Usync from-100 V to-500 V, the film structure changes from amorphous to single-phase corundum, followed by the formation of high-number-density stacking faults (or nanotwins) at Usync =-500 V. This approach paves the way to tailor the high-temperature-phase and defect formation of oxide films at low growth temperature, with prospects for use in protective-coating and dielectric applications., Funding Agencies|VINNOVA Competence Centre FunMat-II [2016-05156]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Link oping University [2009 00971]; Knut and Alice Wallenberg Foundation through the Wallenberg Academy Fellows program [KAW-2020.0196]; Swedish Research Council [VR 2018-04139]; Eurostars program; National Natural Science Foundation of China [51805102, 2019-00191]; Science and Technology Foundation of Guizhou Province; Swedish Research Council VR-RFI [E!114277]; Swedish Foundation for Strategic Research [[2020] 1Y228]; [52165021]; [RIF14- 0053]

The development of abundant, cheap, and highly active catalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is important for hydrogen production. Nanolaminate ternary transition metal carbides (MAX phases) and their derived two-dimensional transition metal carbides (MXenes) have attracted considerable interest for electrocatalyst applications. Herein, four new MAX@MXene core-shell structures (Ta2CoC@ Ta2CTx, Ta2NiC@Ta2CTx, Nb2CoC@Nb2CTx, and Nb2NiC@Nb2CTx), in which the core region is Co/Ni-MAX phases while the edge region is MXenes, have been prepared. Under alkaline electrolyte conditions, the Ta2CoC@Ta2CTx core-shell structure showed an overpotential of 239 mV and excellent stability during the HER with MXenes as the active sites. For the OER, the Ta2CoC@Ta2CTx core- shell structure showed an overpotential of 373 mV and a small Tafel plot (56 mV dec-1), which maintained a bulk crystalline structure and generated Co-based oxyhydroxides that formed by surface reconstruction as active sites. Considering rich chemical compositions and structures of MAX phases, this work provides a new strategy for designing multifunctional electrocatalysts and also paves the way for further development of MAX phase-based materials for clean energy applications., Funding Agencies|Pioneer

Zinc oxide (ZnO) is a thermally stable n-type semiconducting material. ZnO 2D nanosheets have mainly gained substantial attention due to their unique properties, such as direct bandgap and strong excitonic binding energy at room temperature. These are widely utilized in piezotronics, energy storage, photodetectors, light-emitting diodes, solar cells, gas sensors, and photocatalysis. Notably, the chemical properties and performances of ZnO nanosheets largely depend on the nano-structuring that can be regulated and controlled through modulating synthetic strategies. Two synthetic approaches, top-down and bottom-up, are mainly employed for preparing ZnO 2D nanomaterials. However, owing to better results in producing defect-free nanostructures, homogenous chemical composition, etc., the bottom-up approach is extensively used compared to the top-down method for preparing ZnO 2D nanosheets. This review presents a comprehensive study on designing and developing 2D ZnO nanomaterials, followed by accenting its potential applications. To begin with, various synthetic strategies and attributes of ZnO 2D nanosheets are discussed, followed by focusing on methodologies and reaction mechanisms. Then, their deliberation toward batteries, supercapacitors, electronics/optoelectronics, photocatalysis, sensing, and piezoelectronic platforms are further discussed. Finally, the challenges and future opportunities are featured based on its current development., Funding Agencies|SERB; SERB, New Delhi [EMR/2017/003368]

Studies of single crystal artificial superlattices (SLs) of transition-metal (TM) diborides, which is instru- mental to understand hardening mechanisms at nanoscale, is lacking. Here, CrBx/TiBy (0001) diboride SLs [x,y E 1.7-3.3] are grown epitaxially on Al2O3(0001) substrates by direct-current magnetron sputter epitaxy. Growth conditions for obtaining well-defined SLs with good interface quality are found at 4 mTorr Ar pressure and 600 degrees C. 1 -mu m-thick SL films deposited with modulation periods A between 1 and 10 nm, and A=6 nm SLs with TiBy-to-A layer thickness ratios F ranging from 0.2 to 0.8 are studied. SLs with A=6 nm and F in the range of 0.2-0.4, with a near stoichiometric B/TM ratio, exhibit the high- est structural quality. The effects of F and stoichiometries (B/TM ratio) on the distribution of B in the SL structures are discussed. By increasing the relative thickness of TiBy, the crystalline quality of SLs starts to deteriorate due to B segregation in over-stoichiometric TiBy, resulting in narrow epitaxial SL columnar growth with structurally-distorted B-rich boundaries. Moreover, increasing the relative thickness of under-stoichiometric CrBx enhances the SL quality and hinders formation of B-rich boundaries. The SLs are found to exhibit hardness values in the range of 29-34 GPa.(c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)., Funding Agencies|Swedish National Graduate School in Neutron Scattering (SwedNess); Swedish Foundation for Strategic Research (SSF) [GSn15 -0008]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials (AFM) at Linkoeping University (Faculty Grant SFO Mat LiU) [2009 00971]; Swedish Research Council VR [2019-00191, 2021-00357]; Knut and Alice Wallenberg Foundation [KAW 2015.0043]

An innovative modular approach for facile design and construction of flexible microfluidic biosensor platforms based on a dry manufacturing "craft-and-stick" approach is developed. The design and fabrication of the flexible graphene paper electrode (GPE) unit and polyethylene tetraphthalate sheet (PET)6/adhesive fluidic unit are completed by an economic and generic xurographic craft approach. The GPE widths and the microfluidic channels can be constructed down to 300 mu m and 200 mu m, respectively. Both units were assembled by simple double-sided adhesive tapes into a microfluidic integrated GPE (MF-iGPE) that are flexible, thin (<0.5 mm), and lightweight (0.4 g). We further functionalized the iGPE with Prussian blue and glucose oxidase for the fabrication of MF-iGPE glucose biosensors. With a closed-channel PET fluidic pattern, the MF-iGPE glucose biosensors were packaged and sealed to protect the integrated device from moisture for storage and could easily open with scissors for sample loading. Our glucose biosensors showed 2 linear dynamic regions of 0.05-1.0 and 1.0-5.5 mmol L-1 glucose. The MF-iGPE showed good reproducibility for glucose detection (RSD < 6.1%, n = 6) and required only 10 mu L of the analyte. This modular craft-and-stick manufacturing approach could potentially further develop along the concept of paper-crafted model assembly kits suitable for low-resource laboratories or classroom settings., Funding Agencies|Royal Golden Jubilee Ph.D. Scholarship from the Thailand Research Fund under the Office of the Prime Ministry, the Royal Thai Government [PHD/0213/2560]

Electrochemical devices as conducting polymer-based actuators or textile actuators often use layers of different conducting polymers. Although research has been performed on such devices, it is still not very clear how the different layers affect each other. Here we attempt to clarify such influence on yarn actuators using electrochemical methods. Different electrochemical methods as cyclic voltammetry, chronoamperometry or chronopotentiometry were used to electropolymerize polypyrrole on top of a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) coated textile yarns by using different applied electrochemical conditions (potentials/currents). Thus, we found that selecting suitable conditions (as an applied potential of +0.8 V) for such electropolymerization is key to obtain a polypyrrole of high quality. Besides, we show that the underlying layer of PEDOT:PSS has an influence on such electropolymerization conditions and can be subjected to parallel redox reactions as oxidation or electrochemical degradation that influence the electropolymerized polypyrrole., Funding Agencies|Promobilia Foundation [F17603, A21024, A21029, A22122]; European Union [2020-0054]; Linkoeping University; The Erling-Persson Family Foundation; [825232]

Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate(PEDOT:PSS)is one of the most important mixed electron-ion conducting polymers,where the efficiency of the ion transport is crucial for many of itsapplications. Despite the impressive experimental progress in thedetermination of ionic mobilities in PEDOT:PSS, the fundamentals ofion transport in this material remain poorly understood, and the theoreticalinsight into the ion diffusion on the microscopical level is completelymissing. In the present paper, a Martini 3 coarse-grained moleculardynamics (MD) model for PEDOT:PSS is developed and applied to calculatethe ion diffusion coefficients and ion distribution in the film. Wefind that the ion diffusion coefficients for Na+ ions arepractically the same in the PEDOT-rich and PSS-rich regions and donot show sensitivity to the oxidation level. We compare the calculateddiffusion coefficients with available experimental results. Basedon this comparison and based on the MD morphology simulation of PEDOT:PSSrevealing the formation of pores inside the film, we revise a commonlyaccepted granular morphological model of PEDOT:PSS. Namely, we arguethat PEDOT:PSS films, in addition to PEDOT-rich and PSS-rich regions,must contain a network of pores where the ion diffusion takes place., Funding Agencies|Wallenberg Wood Science Center; Knut and Alice Wallenberg Foundation (project "H2O2"); Swedish e-Science Research Centre (SeRC)

Phase formation, morphology, and optical properties of Ti(O,N) thin films with varied oxygen-to- nitrogen ration content were investigated. The films were deposited by magnetron sputtering at 500 & DEG;C on Si(100) and c-plane sapphire substrate. A competition between a NaCl B1 structure TiN1-xOx, a rhombohedral structure Ti-2(O1-yNy)(3), and an anatase structure Ti(O1-zNz)(2) phase was observed. While the N-rich films were composed of a NaCl B1 TiN1-xOx phase, an increase of oxygen in the films yields the growth of rhombohedral Ti-2(O1-yNy)(3) phase and the oxygen-rich films are comprised of a mixture of the rhombohedral Ti-2(O1-yNy)(3) phase and anatase Ti(O1-zNz)(2) phase. The optical properties of the films were correlated to the phase composition and the observation of abrupt changes in terms of refractive index and absorption coefficient. The oxide film became relatively transparent in the visible range while the addition of nitrogen into films increases the absorption. The oxygen rich-samples have bandgap values below 3.75 eV, which is higher than the value for pure TiO2, and lower than the optical bandgap of pure TiN. The optical properties characterizations revealed the possibility of adjusting the band gap and the absorption coefficient depending on the N-content, because of the phases constituting the films combined with anionic substitution., Funding Agencies|KKL Advanced Materials, LNU [87202002]; Crafoord Foundation [2022-0692]; Knut and Alice Wallenberg foundation through the Wallenberg Academy Fellows program [KAW-2020.0196]; Swedish Energy Agency [52740-1and 46519-1]

The electrochemical performance of NiCo2O4 with urea precursors was evaluated in order to develop a non-enzymatic urea sensor. In this study, NiCo2O4 nanostructures were synthesized hydrothermally at different concentrations of urea and characterized using scanning electron microscopy and X-ray diffraction. Nanostructures of NiCo2O4 exhibit a nanorod-like morphology and a cubic phase crystal structure. Urea can be detected with high sensitivity through NiCo2O4 nanostructures driven by urea precursors under alkaline conditions. A low limit of detection of 0.05 and an analytical range of 0.1 mM to 10 mM urea are provided. The concentration of 006 mM was determined by cyclic voltammetry. Chronoamperometry was used to determine the linear range in the range of 0.1 mM to 8 mM. Several analytical parameters were assessed, including selectivity, stability, and repeatability. NiCo2O4 nanostructures can also be used to detect urea in various biological samples in a practical manner., Funding Agencies|Higher Education Commission Pakistan [NRPU/8350]; King Saud University, Riyadh, Saudi Arabia; Ajman University; [RSP2023R79]; [2022-IRG-HBS-5]