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Highlights: Atomically dispersed metal atoms effectively enhance energy level alignment and reduce energy losses at the electrode interfaces. The optimized carbon-based perovskite solar cells achieve a power conversion efficiency (PCE) of 22.61% and maintain 94.4% of their initial PCE after 1000 h under continuous illumination without encapsulation. Carbon-based perovskite solar cells (C-PSCs) exhibit notable stability and durability. However, the power conversion efficiency (PCE) is significantly hindered by energy level mismatches, which result in interfacial charge transport barriers at the electrode-related interfaces. Herein, we report a back electrode that utilizes atomically dispersed metallic cobalt (Co) in carbon nanosheets (Co1/CN) to adjust the interfacial energy levels. The electrons in the d-orbitals of Co atoms disrupt the electronic symmetry of the carbon nanosheets (CN), inducing a redistribution of the electronic density of states that leads to a downward shift in the Fermi level and a significantly reduced interfacial energy barrier. As a result, the C-PSCs using Co1/CN as back electrodes achieve a notable PCE of 22.61% with exceptional long-term stability, maintaining 94.4% of their initial efficiency after 1000 h of continuous illumination without encapsulation. This work provides a promising universal method to regulate the energy level of carbon electrodes for C-PSCs and paves the way for more efficient, stable, and scalable solar technologies toward commercialization. [ABSTRACT FROM AUTHOR]

All that remains to reliably beat the 20% efficiency hurdle in organic solar cells are the relatively low open‐circuit voltages (VOC). A still‐needed step toward solving this problem is to shed light on the mechanisms behind these losses, and herein it is focused on understanding the roll‐off of VOC at low temperatures, which has been linked to various detrimental processes. Here, a light intensity sweep is added to the temperature‐dependent measurements and the resulting trends are compared with a kinetic analytical model that not only incorporates all previously suggested explanations for the temperature dependence of VOC, but, importantly, also includes carrier density contributions to the electron and hole mobilities by treating the density of states (DOS) of the active layer as a two‐level system. It is found that this description is sufficient to quantitatively explain VOC roll‐off in terms of charges getting trapped in intrinsic tail states of the Gaussian DOS without having to assume the presence of extrinsic traps. [ABSTRACT FROM AUTHOR]

This paper deals with the analysis of an instationary drift-diffusion model for perovskite solar cells including Fermi–Dirac statistics for electrons and holes and Blakemore statistics for the mobile ionic vacancies in the perovskite layer. The free energy functional is related to this choice of the statistical relations.Exemplary simulations varying the mobility of the ionic vacancy demonstrate the necessity to include the migration of ionic vacancies in the model frame. To prove the existence of weak solutions, first a problem with regularized state equations and reaction terms on any arbitrarily chosen finite time interval is considered. Its solvability follows from a time discretization argument and passage to the time-continuous limit. Applying Moser iteration techniques, a priori estimates for densities, chemical potentials and the electrostatic potential of its solutions are derived that are independent of the regularization level, which in turn ensure the existence of solutions to the original problem. [ABSTRACT FROM AUTHOR]

An exceptionally brilliant strategy to miniaturize electronic devices is to employ a single‐molecule between two electrodes for carrier conduction at single‐molecule break junctions (SMBJ). To understand the intrinsic mechanisms of operation at these junctions, extremely crucial is to study physical, chemical, and electrochemical properties employing single‐molecules at SMBJs. Further, redox‐based transformations at the nano‐junction could be achieved electrochemically to allow efficient switching between different redox states of a single‐molecule, showcasing the possibility of maneuvering transport properties with on‐off states of the molecule. Herein, are presented the fundamentals of SMBJs, and the electrochemically influenced transformations or switching of organic molecules pursued at SMBJs. Such an understanding of electrochemical phenomena at the nanoscale dimension could bridge the knowledge gap between macroscopic electronic circuits and single‐molecule electronic circuits, whereby the feasibility of switching between the states could maneuver the electronic properties as well as other photophysical parameters. [ABSTRACT FROM AUTHOR]

Perovskite optoelectronics are regarded as a disruptive technology, but their susceptibility to environmental degradation and reliance on toxic solvents in traditional processing methods pose significant challenges to their practical implementation. Herein, methylammonium lead iodide (MAPbI3) perovskite films processed via a solvent‐free laser printing technique, that exhibit exceptional stability, are reported. These films withstand extreme conditions, including high doses of X‐ray radiation exceeding 200 Gy, blue laser illumination, 90% relative humidity, and thermal stress up to 80 °C for over 300 min in air. We demonstrate that laser‐printed films maintain their structural integrity and optoelectronic properties even after prolonged exposure to these stressors, significantly surpassing the stability of conventionally processed films. The enhanced stability is attributed to the unique film formation mechanism and resulting defect‐tolerant microstructure. These results underscore the potential of laser printing as a scalable, safe, and sustainable manufacturing route for producing stable perovskite‐based devices with potential applications in diverse fields, ranging from renewable energy to large‐area electronics and space exploration. [ABSTRACT FROM AUTHOR]

The influence of ordering inside the crystalline regions of semi‐crystalline polymer thin films on charge transport is investigated by analyzing the electric field dependence of mobility calculated using Monte Carlo simulation. The degree of ordering inside the ordered regions is varied by changing the overlap between the hopping transport sites. Negative field dependence of mobility extending to higher electric field strengths along with an increase in the mobility are observed upon increasing the overlap between transport sites inside the ordered region. These observations are attributed to the variation in the charge transport, which affects the transit time that not only decreases but also shows a gradual shift from negative to positive field dependence at lower electric field strengths (∼<3 × 105 V/cm). Variations in the transit time are explained using the variation in the field dependence of hops performed by the carrier inside the ordered and disordered regions. Field dependence of mobility is also simulated with ballistic charge transport inside the ordered regions. At low concentrations of ordered regions (COR), higher carrier mobility is attained with hopping transport (∼<70%). Ballistic transport provides higher mobility at higher COR (∼>70%). This suggests that a very high order inside the ordered region may not necessarily provide higher mobility. [ABSTRACT FROM AUTHOR]

The future of next‐generation electronics relies on low‐cost organic semiconductors that are tailored to simultaneously provide all requisite optoelectronic properties, focusing greatly on ambipolar charge‐transport and solution processability. In this regard, room‐temperature discotic liquid crystals (DLCs) are potential candidates, where quasi‐1D self‐assembly affords a charge‐transport channel along their columnar axis. This work shows a molecular design strategy by utilizing anthraquinone as the primary motif, surrounded by ester functionalized tri‐alkoxy phenyl units to develop room‐temperature DLCs (1.1–1.3). Here, the polar ester functionality stabilizes the columnar mesophase over a wide range through the involvement of dipole‐dipole interaction along with the π–π stacking. Throughout the entire mesophase transition, reported compounds 1.1–1.3 exhibit a highly ordered 2D columnar oblique (Colob) self‐assembly. Space charge limited current (SCLC) experiments reveal balanced ambipolar charge transport, with the maximum hole and electron mobilities of 5.04 and 4.93 cm2 V−1 s−1, respectively. From the conoscopic results, their propensity to align in a highly homeotropic fashion is demonstrated. It is further justified by the azimuthal plot corresponding to the (11) peak of grazing incidence small angle X‐ray scattering (GISAXS), denoting the crucial role of the design and alignment for efficient movement of charge carriers in the material. [ABSTRACT FROM AUTHOR]

The advancement and meticulous design of functional photocatalysts exhibiting exceptional photocatalytic redox activity represent a pivotal approach to mitigating the dual challenges of environmental pollution and energy scarcity. In this study, we elucidate the construction of a Bi 2 O 2 CO 3 catalytic system capable of inhibiting oxidative electron transfer through the attenuation of homogeneous Bi0 particle formation, achieved through the judicious modulation of solvent ratios. This innovative architecture possesses a distinctive active site and enhances interfacial Bi-O electron transfer pathways via exposure to oxidized Bi3+. Upon photoexcitation, the Bi 2 O 2 CO 3 catalytic system undergoes structural distortions in its excited state that facilitate forbidden radiative relaxation, thereby fostering long-lived charge separation states. Remarkable catalytic activity was demonstrated in the remediation of pollutants, encompassing auto-oxidation and the catalytic degradation of superoxide radicals (•O 2 −) and holes (h+). Notably, the effective degradation of tetracycline hydrochloride (TCH) in aqueous media reached an impressive 86 % under simulated visible light irradiation, accompanied by a reaction rate constant 3.08 times superior to that of the 5-Bi/Bi 2 O 2 CO 3 counterpart. Theoretical analyses revealed that the oxidized state of Bi 2 O 2 CO 3 exhibits a crystal structure with significant electron trapping capability, undergoing pronounced apparent relaxation phenomena on its surface while demonstrating an enhanced adsorption affinity for H 2 O and O 2. The potential degradation mechanisms were rigorously investigated through High-performance liquid chromatography (HPLC-MS), elucidating the photodegradation pathways and intermediates of TC. This work may serve as a distinct paradigm for the rational design of novel photocatalysts aimed at fostering sustainable environmental remediation and advancing energy innovation. [ABSTRACT FROM AUTHOR]

Traditionally used phenylethylamine iodide (PEAI) and its derivatives, such as ortho‐fluorine o‐F‐PEAI, in interfacial modification, are beneficial for perovskite solar cell (PSC) efficiency but vulnerable to heat stability above 85 °C due to ion migration. To address this issue, we propose a composite interface modification layer incorporating the discotic liquid crystal 2,3,6,7,10,11‐hexa(pentoxy)triphenylene (HAT5) into o‐F‐PEAI. The triphenyl core in HAT5 promotes π–π stacking self‐assembly and enhances its interaction with o‐F‐PEAI, forming an oriented columnar phase that improves hole extraction along the one‐dimensional direction. HAT5 repairs structural defects in the interfacial layer and retains the layered structure to inhibit ion migration under heating. Ultimately, our approach increases the efficiency of solar cells from 23.36 % to 25.02 %. The thermal stability of the devices retains 80.1 % of their initial efficiency after aging at 85 °C for 1008 hours without encapsulation. Moreover, the optimized PSCs maintained 82.4 % of the initial efficiency after aging under one sunlight exposure for 1008 hours. This work provides a simple yet effective strategy using composite materials for interface modification to enhance the thermal and light stability of semiconductor devices. [ABSTRACT FROM AUTHOR]

One key aspect for the development of functional molecular electronic devices is the ability to precisely tune and reversibly switch the conductance of individual molecules in electrode‐molecule‐electrode junctions in response to external stimuli. In this work, we present a new approach to access molecular switches by deliberately controlling the flexibility in the molecular backbone. We here describe two new conductance switches based on bis(triarylamines) that rely on the reversible toggling between two conformers, each associated with vastly different conductances. By molecular design, we were able to realize an on/off ratio Ghigh/Glow of ~103, which is one of the largest values reported to date. Flicker noise analysis and molecular transport calculations indicate that on/off switching relies on a change of the conduction pathway and vast differences in molecule‐electrode coupling. We thereby provide a new scaffold for further development of molecular conductance switches that are both efficient and easily refined. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Tin oxide (SnO2) has been widely used as an electron transport layer (ETL) in optoelectronic devices. However, there are numerous surface or bulk defects in SnO2, working as charge recombination centers to degrade device. Here, an electroactive and self‐healing polyurethane (PHNN) was designed by integrating conjugated unit – naphthalene diimide (NDI) into a typical polyurethane backbone. Numerous hydrogen bonds and π interactions in PHNN work as non‐covalent interactions to endow this polymer with superior self‐healing properties. PHNN contains lots of aliphatic amine and carbonyl groups, which effectively passivate the defects in SnO2. The π stacking of NDI units will facilitate electron delocalization, endowing PHNN with electrical activity compared with traditional polyurethane. Doping SnO2 with PHNN can improve the conductivity and reduce the work function of SnO2 layer, which is conducive to efficient charge extraction and transport. Using PHNN doped SnO2 as ETL for PM6: Y6 and PM6: BTP‐eC9 based inverted organic solar cells can achieve a high efficiency of 17.16% and 17.51%, respectively. Devices containing doped SnO2 ETL show significantly improved efficiency and stability. Thus, the electroactive polyurethane doped SnO2 interlayers show high performance interfacial modification to align energy‐levels in solar cell devices, which have promising applications in organic electronics. [ABSTRACT FROM AUTHOR]

Hydrothermally grown NiO nanoflakes have been investigated here for their resistive switching (RS) and photoabsorption characteristics. The formation and disruption of the conducting filament (CF) under an applied external electric field leads to bistable resistive switching in the grown NiO nanoflakes. Comprehensive investigations of the I–V behaviour show that the formation and rupturing of the CF depend on the concentration of the metallic Ni. Interestingly, photoabsorption response demonstrates a nearly similar behaviour in UV and visible regions for nanoflakes grown at low reaction time, but an enhanced UV response for the flakes obtained at larger reaction times. These nanoflakes displaying multifunctional properties of photoabsorption and RS behaviour, that can be modulated with reaction time, are attractive for optoelectronic, electrochromic and RS-based memory applications. [ABSTRACT FROM AUTHOR]

A novel 2-(2,3,4-trimethoxyphenyl)-1H-phenanthro[9,10-d]imidazole crystal has been reported and characterized by FT-IR, 1H NMR, and 13C NMR spectral techniques. Single-crystal XRD studies reveal that the compound crystallizes into orthorhombic crystal system with Pbcn space group, and crystallographic data have been deposited in the Cambridge crystallographic data centre with CCDC number: 2244532. Various computational analyses such as hydrogen bond analysis, molecular electrostatic potential analysis, natural population analysis, Hirshfeld surface, and Frontier molecular orbital analysis were performed to elucidate the structure of the crystal. The calculation of reorganization energy and coupling constant using DFT methods reveals that the compound could be investigated as a hole transport material. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Tin oxide (SnO2) has been widely used as an electron transport layer (ETL) in optoelectronic devices. However, there are numerous surface or bulk defects in SnO2, working as charge recombination centers to degrade device. Here, an electroactive and self‐healing polyurethane (PHNN) was designed by integrating conjugated unit – naphthalene diimide (NDI) into a typical polyurethane backbone. Numerous hydrogen bonds and π interactions in PHNN work as non‐covalent interactions to endow this polymer with superior self‐healing properties. PHNN contains lots of aliphatic amine and carbonyl groups, which effectively passivate the defects in SnO2. The π stacking of NDI units will facilitate electron delocalization, endowing PHNN with electrical activity compared with traditional polyurethane. Doping SnO2 with PHNN can improve the conductivity and reduce the work function of SnO2 layer, which is conducive to efficient charge extraction and transport. Using PHNN doped SnO2 as ETL for PM6: Y6 and PM6: BTP‐eC9 based inverted organic solar cells can achieve a high efficiency of 17.16% and 17.51%, respectively. Devices containing doped SnO2 ETL show significantly improved efficiency and stability. Thus, the electroactive polyurethane doped SnO2 interlayers show high performance interfacial modification to align energy‐levels in solar cell devices, which have promising applications in organic electronics. [ABSTRACT FROM AUTHOR]

Global warming and environmental pollution from fossil fuels have spurred the need for clean energy technologies, among which thermoelectric (TE) devices are promising due to their ability to convert waste heat into electricity. Conducting polymers, particularly poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), have emerged as notable organic TE materials owing to their inherent low thermal conductivity, non-toxicity, and mechanical flexibility. PEDOT:PSS exhibits good stability under high doping level, yielding high electrical conductivity over 1000 S cm−1. This review focuses on the enhancement of the TE performance of PEDOT:PSS through strategies such as post-solvent treatments to selectively remove excess PSS, thereby improving charge carrier mobility and electrical conductivity. Additionally, modifying the interaction between PEDOT and PSS can optimize the macro- and microstructure, leading to improved charge transport properties. The formation of PEDOT:PSS nanocomposites further enhances the Seebeck coefficient and electrical conductivity by enabling effective energy-filtering and improved charge transport pathways. These advancements underscore the potential of PEDOT:PSS in developing efficient, flexible, and stable TE generators for various applications. Strategies to improve thermoelectric performance of PEDOT:PSS [ABSTRACT FROM AUTHOR]

The I-V characteristics of heterostructures n-GaAs – p-(ZnSe)1–x–y(Ge2)x(GaAs1–δBiδ) exhibit a characteristic quadratic law - J~V2 I-V curve, followed by a sharp pre-breakdown current growth, which well explains the observed straight branch of the I-V characteristics and this regularity remains unchanged at different temperatures. The analysis of the I-V characteristics of n‑GaAs‑p‑(ZnSe)1‑x‑y(Ge2)x(GaAs1–δBiδ) heterostructures with an extended intermediate solid solution layer shows that the drift mechanism of charge transport predominates under forward bias conditions.

Antimony-based perovskites have been recognized for their distinctive optoelectronic attributes, standard fabrication methodologies, reduced toxicity, and enhanced stability. The objective of this study is to systematically investigate and enhance the performance of all-inorganic solar cell architectures by integrating Cs3Sb2I9, a perovskite-analogous material, with WS2—a promising transition metal dichalcogenide—used as the electron transport layer (ETL), and Cu2O serving as the hole transport layer (HTL). This comprehensive assessment extends beyond the mere characterization of material attributes such as layer thickness, doping levels, and defect densities, to include a thorough investigation of interfacial defect effects within the structure. Optimal efficiency was observed when the Cs3Sb2I9 absorber layer thickness was maintained within the 600-700 nm range. The defect tolerance for the absorber layer was identified at 1×1015/cm3, with the ETL and HTL layers exhibiting significant defect tolerance at 1×1016/cm3 and 1×1017/cm3, respectively. Furthermore, this study calculated the minority carrier lifetime and diffusion length, establishing a strong correlation with defect density; a minority carrier lifetime of approximately 1 µs was noted for a defect density of1×1014/cm3 in the absorber layer. A noteworthy finding pertains to the balance between the high work function of the back contact and the incorporation of p-type back surface field layers, revealing that interposing a highly doped p+ layer between the Cu2O and the metal back contact can elevate the efficiency to 21.60%. This approach also provides the freedom to select metals with lower work functions, offering a cost-effective advantage for commercial-scale applications.

A promising candidate for X‐ray detection is layered hybrid double perovskites (LHDPs) with excellent structural stability, but their sensitivity is generally limited by unsatisfactory interlayer charge transport. Herein, employing one ethylenediamine (EDA) chain as a structural inducer, we successfully obtain unusual Dion‐Jacobson (DJ) phase LHDPs, (EDABr)4AgBiBr8 and (EDABr)4CuBiBr8, featuring a Ruddlesden‐Popper‐like (RP‐like) interlayer. Thanks to the bridging of bromine anions, organic cations are linked via charge‐assisted hydrogen bonds, where two ionic spacers are orderly woven into a supramolecular framework. Consequently, the RP‐like interlayer space is regulated by the dual‐ion‐woven supramolecular framework with embedded charge‐assisted hydrogen bond networks, remarkably enriching interlayer interactions and boosting charge transport. Through theoretical calculations, structural roles of the supramolecular framework are elucidated by extra orbital contribution and large diffusion barrier of Br anions. As proof of concept, the sensitivity of RP‐like devices up to 5250 μC Gyair−1 cm−2 is a record‐high of LHDP‐based X‐ray detectors for now, while a low detection limit (91 nGyair s−1) and outstanding radiation‐resistant capability (50 Gyair) are achieved. Moreover, an oriented membrane device is prepared to demonstrate high‐performance X‐ray tomography. These findings offer a brand‐new interlayer‐modulation strategy for the construction of sensitive and stable scintillation semiconductors. [ABSTRACT FROM AUTHOR]

The polymorphic behavior of conjugated polymers enables tunable optoelectronic properties, but their transport mechanism remains elusive due to the inherent complexity and uncontrollability of polymorphic self‐assembly behaviors and electronic processes at various length scales, alongside the ambiguous relationship between solution and solid states. Herein, precise control of multi‐level supramolecular self‐assembly of a polymorphic conjugated polymer, N‐PDPP4T‐HD with two distinct semi‐crystalline aggregated phases (β1 and β2) via solvent engineering is demonstrated. β1 forms 1D worm‐like nanostructures in solution, whereas β2 generates 2D nanoscale lamellar configuration, confirmed by experimental observation and molecular dynamic simulation. Such solution‐state features are inherited in the solid state (1D nanofibers for β1 and 2D granular‐like structures for β2). X‐ray characterizations reveal larger crystalline domains on the nanometer scale, reduced π‐stacking distance on the Ångstrom scale, and diminished paracrystallinity disorder for solid‐state β2. Going beyond conventional DC transistor characterizations, contact‐free ultrafast terahertz spectroscopy to unveil AC short‐range, intrinsic transport properties is employed. Longer charge carrier scattering time and thus intrinsic mobility of β2 result in threefold higher short‐range photoconductivity than β1. This work establishes the "solution structure – solid structure – local transport" relation in polymorphic conjugated polymers and provides new opportunities for high‐performance plastic electronic devices. [ABSTRACT FROM AUTHOR]

Nickel‐doped cobalt bi‐metal nanoparticles (Ni/Co BMNPs) are employed in the transport buffer layer of thin‐film polymer solar cell to assist in the collection of photons generated current. P3HT:PCBM blend‐based polymer solar cells are successfully fabricated with modified hole transport layer (HTL)‐containing BMNPs at different concentrations. The performance of the devices has generally improved compared to the reference cell by the presence of BMNPs in the transport buffer layer, and shows sign of dependence on concentration level. Significant improvements in device performance are recorded at optimum level of 0.05% BMNPs by weight, which resulted in a high current density of 15.31 mA cm−2, and recorded 5.05% power conversion efficiency (PCE). This is 67.8% growth in PCE is compared to the reference cell. Moreover, another investigation is conducted using device simulation program to check the reproducibility of the experiments. The device that is made to mimic the best performance at 0.05% BNMP concentration produced an efficiency of 5.76%. Such reproducibility of data is an important development toward better understanding of the charge transport process in polymer solar cell. This study further provides new evidences about factors that influence device performance due to the inclusion of the BMNPs. [ABSTRACT FROM AUTHOR]

The reversible photo-induced conformation transition of a single molecule with a [5]helicene backbone has garnered considerable interest in recent studies. Based on such a switching process, one can build molecular photo-driven switches for potential applications of nanoelectronics. But the achievement of high-performance reversible single-molecule photoswitches is still rare. Here, we theoretically propose a 13,14-dimethylcethrene switch whose photoisomerization between the ring-closed and ring-open forms can be triggered by ultraviolet (UV) and visible light irradiation. The electronic structure transitions and charge transport characteristics, concurrent with the photo-driven electrocyclization of the molecule, are calculated by the non-equilibrium Green's function (NEGF) in combination with density functional theory (DFT). The electrical conductivity bears great diversity between the closed and open configurations, certifying the switching behavior and leading to a maximum on–off ratio of up to 103, which is considerable in organic junctions. Further analysis confirms the evident switching behaviors affected by the molecule–electrode interfaces in molecular junctions. Our findings are helpful for the rational design of organic photoswitches at the single-molecule level based on cethrene and analogous organic molecules. [ABSTRACT FROM AUTHOR]

Herein, a straightforward vacuum‐assisted method is introduced to enhance the stability of nonfullerene organic solar cells (OSCs). The method, termed "prevacuum" involves subjecting the active layer (D18:Y6) to a low‐pressure vacuum (−1 bar) before thermal annealing at 100 °C. Compared to untreated devices, prevacuum‐treated OSCs exhibit a notable increase in power conversion efficiency from 13.71% to 14.90%. This enhancement is attributed to improved light absorption and charge extraction, as evidenced by external quantum efficiency measurements. Moreover, prevacuum treatment significantly improves device stability under operational conditions, with a 30% power loss occurring after 8.25 h compared to 4.5 h for untreated devices. This improvement is attributed to the removal of volatile components and impurities during the vacuum process, leading to a more hydrophobic and stable active layer. The study demonstrates the efficacy of prevacuum treatment as a simple and accessible method for enhancing the performance and longevity of OSCs, paving the way for their broader application in sustainable energy technologies. [ABSTRACT FROM AUTHOR]

The design of photocatalytic supramolecular systems composing of semiconductors and molecular metal complexes for CO2 reduction has attracted increasing attention. The supramolecular system combines the structural merits of semiconductors and metal complexes, where the semiconductor harvests light and undertakes the oxidative site, while the metal complex provides activity for CO2 reduction. The intermolecular charge transfer plays crucial role in ensuring photocatalytic performance. Here, we review the progress of photocatalytic supramolecular systems in reduction of CO2 and highlight the interfacial charge transfer pathways, as well as their state‐of‐the‐art characterization methods. The remaining challenges and prospects for further design of supramolecular photocatalysts are also presented. [ABSTRACT FROM AUTHOR]

The optoelectronic properties of semiconducting polymers and device performance rely on a delicate interplay of design and processing conditions. However, screening and optimizing the relationships between these parameters for reliably fabricating organic electronics can be an arduous task requiring significant time and resources. To overcome this challenge, Polybot is developed—a robotic platform within a self‐driving lab that can efficiently produce organic field‐effect transistors (OFETs) from various semiconducting polymers via high‐throughput blade coating deposition. Polybot not only handles the fabrication process but also can conduct characterization tests on the devices and autonomously analyze the data gathered, thus facilitating the rapid acquisition of data on a large scale. This work leverages the capabilities of this platform to investigate the fabrication of OFETs using hydrogen bonding‐containing semiconducting polymers. Through high‐throughput fabrication and characterization, various data trends are analyzed, and large extents of anisotropic charge mobility are observed in devices. The materials are thoroughly characterized to understand the role of processing conditions in solid state and electronic properties of these organic semiconductors. The findings demonstrate the effectiveness of automated fabrication and characterization platforms in uncovering novel structure–property relationships, facilitating refinement of rational chemical design, and processing conditions, ultimately leading to new semiconducting materials. [ABSTRACT FROM AUTHOR]

Asymmetric wide‐band gap fullerene‐free acceptors (FFAs) play a crucial role in organic solar cells (OSCs). Here, we designed and synthesized a simple asymmetric coumarin‐anthracene conjugate named CA‐CN with optical band gap of 2.1 eV in a single‐step condensation reaction. Single crystal X‐ray structure analysis confirms various multiple intermolecular non‐covalent interactions. The molecular orbital energy levels of CA‐CN estimated from cyclic voltammetry were found to be suitable for its use as an acceptor for OSCs. Binary OSCs fabricated using CA‐CN as acceptor and PTB7‐Th as the donor achieve a power conversion efficiency (PCE) of 11.13 %. We further demonstrate that the insertion of 20 wt % of CA‐CN as a third component in ternary OSCs with PTB7‐Th : DICTF as the host material achieved an impressive PCE of 14.91 %, an improvement of ~43 % compared to the PTB7‐Th : DICTF binary device (10.38 %). Importantly, the ternary blend enhances the absorption coverage from 400 to 800 nm and improves the morphology of the active layer. The findings highlight the efficacy of an asymmetric design approach for FFAs, which paves the way for developing high‐efficiency OSCs at low cost. [ABSTRACT FROM AUTHOR]

It is now well‐established that ferroelectric domain walls, at which there are discontinuities in polarization, are usually electrically conducting. Yet, there is a dearth of rather basic information on the physics underpinning conductivity. Here, Kelvin Probe Force Microscopy (KPFM)‐based experiments are reported, which allow significant new insights regarding charge transport at domain walls in ErMnO3. In one set of experiments, KPFM is used to spatially map the Hall potential, developed at the surface of polished single crystals. These maps provide direct experimental evidence that n‐type head‐to‐head domain walls arise in otherwise p‐type material. In another set of experiments, the geometry for current flow is restricted, by cutting sub‐micron thick lamellar slices of ErMnO3 (using a Focused Ion Beam microscope). Separate contacts are made to n and p‐type walls and the potential profiles, when driving source‐drain currents, are measured (again using KPFM). Current‐electric field functions showed Ohmic behaviour for p‐type walls, with an intrinsic room temperature conductivity value of ≈0.4Sm−1. The n‐type walls showed non‐Ohmic behaviour and a significantly lower conductivity, supporting the prediction that electrons are in a polaronic state; an upper bound for the room temperature conductivity of the domains themselves is ≈6 × 10−6Sm−1 at 0.1 MVm−1. [ABSTRACT FROM AUTHOR]

The development of n‐type organic thermoelectric materials, especially π‐conjugated small molecules, lags far behind their p‐type counterparts, due primarily to the scarcity of efficient electron‐transporting molecules and the typically low electron affinities of n‐type conjugated molecules that leads to inefficient n‐doping. Herein, the n‐doping of two functionalized (carbonyl vs dicyanovinylene) indenofluorene‐based conjugated small molecules, 2,8‐bis(5‐(2‐octyldodecyl)thien‐2‐yl)indeno[1,2‐b]fluorene‐6,12‐dione (TIFDKT) and 2,2′‐(2,8‐bis(3‐alkylthiophen‐2‐yl)indeno[1,2‐b]fluorene‐6,12‐diylidene)dimalononitrile (TIFDMT) are demonstrated, with n‐type dopant N‐DMBI. While TIFDKT shows decent miscibility with N‐DMBI, it can be hardly n‐doped owing to its insufficiently low LUMO. On the other hand, TIFDMT, despite a poorer miscibility with N‐DMBI, can be efficiently n‐doped, reaching a respectable electrical conductivity of 0.16 S cm−1. Electron paramagnetic resonance measurements confirm the efficient n‐doping of TIFDMT. Based on density functional theory (DFT) calculations, the LUMO frontier orbital energy of TIFDMT is much lower, and its wave function is more delocalized compared to TIFDKT. Additionally, the polarons are more delocalized in the n‐doped TIFDMT. Remarkably, as indicated by the grazing‐incidence wide‐angle X‐ray scattering (GIWAXS), the molecular order for TIFDMT thin‐film is enhanced by n‐doping, leading to more favorable packing with edge‐on orientation and shorter π‐π stacking distances (from 3.61 to 3.36 Å). This induces more efficient charge transport in the doped state. Upon optimization, a decent thermoelectric power factor of 0.25 µWm−1K−2 is achieved for n‐doped TIFDMT. This work reveals the effect of carbonyl vs dicyanovinylene on the n‐doping efficiency, microstructure evolution upon doping and thermoelectric performance, offering a stepping stone for the future design of efficient n‐type thermoelectric molecules. [ABSTRACT FROM AUTHOR]

The incorporation of heteroatoms in the chemical structure of organic molecules has been identified as analogous to the doping process adopted in silicon semiconductors to influence the nature of charge carriers. This strategy has been an eye‐opener for material chemists in synthesizing new materials for optoelectronic applications. Phenanthro[9,10‐a]phenazine‐based mesogens have been synthesized via a cyclo‐condensation pathway involving triphenylene‐based diketone and o‐phenyl diamines. The incorporation of phenazine moiety as discussed in this paper, alters the symmetric nature of the triphenylene. The phenanthro[9,10‐a]phenazine‐based mesogens exhibit hole mobility in the order of 10−4 cm2/Vs as measured by the space‐charge limited current (SCLC) technique. The current density in the SCLC device increases with increasing temperature which indicates that the charge transport is associated with the thermally activated hopping process. This report attempts to elucidate the self‐organization of asymmetric phenanthro[9,10‐a] phenazine in the supramolecular liquid crystalline state and their potential for the fabrication of high‐temperature optoelectronic devices. However, the low charge carrier mobility can be one of the challenges for device performance. [ABSTRACT FROM AUTHOR]

2D Dion–Jacobson (DJ) perovskites show structural stability and tunability and are regarded as promising photovoltaic materials. The spacer cations play an important impact on exciton separation and charge transport of 2D perovskites. Herein, a novel spacer with thiazole as core, 2‐thiazolemethanammonium (AMT), owning characters of small molecular size, delocalized π‐electrons, and strong electron‐withdrawing ability, is introduced to construct 2D DJ perovskites. Owing to the strong orbital coupling between AMT spacer and inorganic layers, the AMT‐based perovskite exhibits type II quantum well structure, which is favorable for exciton separation. On contrary, such interaction does not appear in the DJ perovskite when aliphatic propyldiammonium (PDA), with a similar length, is used as spacer. The AMT spacer can also induce better crystallinity, resulting in reduced defect density and improved charge transport ability. The optimized device based on (AMT)MA3Pb4I13 exhibits a power conversion efficiency (PCE) of 19.69%, which is a record for 2D DJ perovskite solar cells (PSCs) (n ≤ 4). This work provides deep understanding of the impact of aromatic spacer on the electronic structure of 2D DJ perovskites and the corresponding photovoltaic performance and provides a new opportunity toward highly efficient and stable PSCs. [ABSTRACT FROM AUTHOR]

Interfacial defects and energy level mismatches between the perovskite and 2,2′,7,7′‐tetrakis[N,N‐di(4‐methoxyphenyl)amino]‐9,9′‐spirobifluorene (Spiro‐OMeTAD) layers heavily hinder charge transfer, limiting the efficiency and stability of n‐i‐p perovskite solar cells (PSCs). Herein, D‐type TPA, D‐A‐type TPA‐CN, and A‐D‐A‐type DTPA‐CN with triphenylamine units and different interfacial dipoles are designed as multifunctional interfacial layers for n‐i‐p PSCs. Among the three molecules, A‐D‐A‐type DTPA‐CN has the largest dipole moment, hole transporting capability, and hydrophobicity, and therefore the strongest passivation of interfacial defects and the best carrier extraction efficiency can be observed. As a result, the DTPA‐CN‐treated device achieves a champion power conversion efficiency (PCE) of 25.00%, as compared to the control device (22.78%). Moreover, the long‐term stability of the unencapsulated device is significantly improved. After 2,040 h of storage in a nitrogen glove box, the device maintains over 90% of its initial efficiency, while only 61% for the control device. The work indicates that simultaneous improvement of trap passivation and hole extraction is critical for achieving highly efficient and stable n‐i‐p PSCs. [ABSTRACT FROM AUTHOR]