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Extraction of uranium from seawater could be capable of meeting the maintenance supply of nuclear energy fuel for thousands of years into the future. However, the low capture capacity of conventional microporous adsorbents for uranyl ions is attributed to the electrostatic repulsion of the adsorbed ions, which hinders the migration of foreign metal ions inside the pore channels. Here, we adopt silica of 10–20 nm size as a template to obtain two porous aromatic framework (PAF) adsorbents with mesoporous cavities. Meso-PAFs provide large channels for the rapid adsorption of uranyl ions with a capacity of ∼200 mg g−1 in 1 h (∼10 ppm). Notably, they exhibit an average adsorption capacity of 12.4 mg g−1 during a 20-day extraction from natural seawater, nearly tenfold higher than that of the classical amidoxime-based microporous materials (POP-AO, 1.32 mg g−1). This study provides inspiration for preparing PAFs containing mesoporous channels to provide large enrichment space and alleviate electrostatic repulsion, suggesting a reliable scheme for the future high-performance extraction of nuclear energy from seawater. [ABSTRACT FROM AUTHOR]

Transition metal/nitrogen-doped carbon catalysts (M–N–C) show superior catalytic activity in electrocatalytic CO2 reduction due to their high atomic efficiency. In this work, a series of electrocatalysts with cobalt phthalocyanine (CoPc) highly dispersed on M–N–C were prepared. Compared to the pure M–N–C materials, all CoPc/M–N–C catalysts showed a significantly enhanced activity for CO2 reduction and suppressed hydrogen evolution reaction. Among these catalysts, CoPc/Fe–N–C exhibits an outstanding activity and selectivity for CO2 reduction with 99% faradaic efficiency for CO at a potential of −0.48 V vs. RHE. Obviously, such a composite strategy is considered as one of the effective methods to improve the selectivity of CO2 to CO. [ABSTRACT FROM AUTHOR]

The development of non-noble metal catalysts that exhibit high performance in the dehydrogenation of ammonia borane has been considered a safe and efficient method for hydrogen generation. In this study, a series of CuxCoy alloy nanoparticles with different ratios were highly dispersed on a core–shell microsphere carrier, and the carrier was prepared using carbon spheres as a template. The catalytic activity for H2 from ammonia borane (NH3BH3, AB) hydrolysis was investigated by adjusting the ratio of Cu2+ to Co2+ doping in the catalyst. The Co1Cu1/C@Cu0.76Co2.24O4 core–shell heterostructure catalyst shows excellent catalytic activity with a high turnover frequency (TOF) value of 82.58 molH2 molcat−1 min−1 and a low activation energy (Ea) of 16.06 kJ mol−1. Detailed analysis indicates that the outstanding activity of AB for hydrolytic dehydrogenation could be attributed to the unique core–shell hetero-structures and high dispersion of the CuCo alloy nanoparticles. [ABSTRACT FROM AUTHOR]

The exploitation of highly active and stable catalysts for reduction of CO2 and water oxidation is one of the approaches to facilitate scalable and sustainable CO2 reduction potentially at the industrial scale. Herein, a feasible strategy to rationally build an overall CO2 + H2O electrocatalytic reaction device is the preparation and matchup of a high-performance CO2 reduction catalyst and low-cost and highly active oxygen anode catalyst. A heterostructured nanosheet, γ-NiOOH/NiCO3/Ni(HCOO)2, exhibited superior catalytic activity in the oxygen evolution reaction, and was integrated with CoPc/Fe–N–C to build an overall CO2 + H2O cell with a current density of 10 mA cm−2 at a very low cell voltage of 1.97 V, and the faradaic deficiency of CO2 to CO was maintained at greater than 90% at 1.9 V. [ABSTRACT FROM AUTHOR]

Cutaneous squamous cell carcinoma (cSCC) is one of the most common skin cancers with increasing incidence worldwide. However, it is still challenging to prevent the relapse of cSCC due to poor drug penetration across the stratum corneum. Herein, we report the design of a microneedle patch loaded with MnO2/Cu2O nanosheets and combretastatin A4 (MN-MnO2/Cu2O-CA4) for the enhanced therapy of cSCC. The prepared MN-MnO2/Cu2O-CA4 patch could effectively deliver adequate drugs locally into the tumor sites. Moreover, the glucose oxidase (GOx)-mimicking activity of MnO2/Cu2O could catalyze glucose to produce H2O2, which combined with the released Cu to induce a Fenton-like reaction to efficiently generate hydroxyl radicals for chemodynamic therapy. Meanwhile, the released CA4 could inhibit cancer cell migration and tumor growth by disrupting the tumor vasculature. Moreover, MnO2/Cu2O was endowed with the ability of photothermal conversion under the irradiation of near-infrared (NIR) laser, which could not only kill the cancer cells but also promote the efficiency of the Fenton-like reaction. Significantly, the photothermal effect did not compromise the GOx-like activity of MnO2/Cu2O, which guaranteed enough production of H2O2 for the sufficient generation of hydroxyl radicals. This work may open avenues for constructing MN-based multimodal treatment for the efficient therapy of skin cancers. [ABSTRACT FROM AUTHOR]

The great clinical success of cisplatin and its derivatives has convinced people that metal complexes could play a more significant role in human cancer therapy. However, targeting and drug resistance are still two dominant problems that need to be urgently solved for metallodrugs' efficacy and clinical translation. As an important component of metal complexes, organometallics have been experiencing rapid development in recent years. Compared with platinum drugs, emerging anti-tumor organometallics targeting dynamic bioprocesses provide an effective strategy to overcome conventional problems. This review focuses on burgeoning anti-tumor strategies and provides up-to-date advances in anti-tumor organometallics development based on their action mechanisms. Specifically, important tumor-overexpressed proteins and nucleic acids as organometallics' anti-tumor targets are systematically presented, followed by organometallics that exert their anti-tumor activity by perturbing tumor intracellular energy/redox/metal/immune homeostasis. Finally, nine cell death pathways including apoptosis, paraptosis, autophagy, oncosis, necrosis, necroptosis, ferroptosis, pyroptosis, and immunogenic cell death (ICD) that can be induced by organometallics are reviewed, and their morphological and biochemical features are summarised. This review at the interface of chemistry, biology, and medicine aims to enlighten the rational development of organometallic anti-tumor agents. [ABSTRACT FROM AUTHOR]

Organic molecule doping is one of the main strategies to enhance the performance and sustainability of organometal halide perovskite polycrystalline films. However, the mechanisms for interpreting organic molecule doping are poorly understood, limiting the development of perovskite solar cells (PSCs). Herein, we revisit regular perovskite films and study the doping effects of two typical organic molecules. With PCBM and PMMA doping, the CH3NH3PbI3 films showed higher homogeneity in their crystalline structure, chemical composition, surface topography and potential. The binding of organic molecules to PbI2 inhibited the migration of Pb and the aggregation of CH3NH3+ vacancies. PMMA induced the formation of CH3NH3PbI3 nanofibers, which bridged the grains and increased the intergrain connectivity. The CH3NH3PbI3 films doped with organic molecules showed a five-fold increase in photoexcited carrier lifetime (>1 μs) with an enhanced photoelectric conversion efficiency and stability. Our work offers insight into the doping of organic molecules in perovskite films and paves the way for the further optimization of PSCs. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) crystals of conjugated polymers (2DCCPs) have attracted significant attention in the past few decades due to their superior and intriguing optoelectronic properties. With the increase in brain-inspired neuromorphic computing, 2DCCPs have also been employed in the construction of synaptic devices because they offer clear advantages of easy integration, high stability, long–range order and no biological rejection. However, pursuing controllable strategies to obtain high-quality and large-scale 2DCCPs remains a challenge on account of their intrinsic complex structures. Herein, we present a universal methodology to grow centimeter-scale 2DCCPs in a controlled manner within minutes by selecting an appropriate growth-assisting solvent and surfactant. The thickness of the as-produced 2DCCPs was down to two molecular layers. The photonic synaptic transistors based on the as-grown 2DCCPs could perform typical synaptic functions, including short-term plasticity, paired-pulse facilitation, long-term plasticity and spike intensity-dependent plasticity. The transistor was also proven to have potential application as a high-pass filter. This methodology shows great potential to be expanded to many other polymer systems and opens new pathways for large-area integrated wireless communication systems and artificial visual systems. [ABSTRACT FROM AUTHOR]

A POM-based one-dimensional (1D) chain compound, {BW12O40[Cu(2,2′-bipy)2]2[Cu(2,2′-bipy)(H2O)]}{BW12O40[Cu(2,2′-bipy)2][Cu(2,2′-bipy)(H2O)2]}·7H2O, has been synthesized and structurally characterized, which represents an unprecedented 1D double chain structure with opposite charges. In contrast to common POMs, this compound exhibits a relatively high electrical conductivity of 1.17 × 10−9 S cm−1 at 25 °C. In addition, its semiconducting properties have also been investigated by application of photoelectrochemical sensing of H2O2. [ABSTRACT FROM AUTHOR]

The advent of two-dimensional transition metal dichalcogenides (2D-TMDs) has led to an extensive amount of interest amongst scientists and engineers alike and an intensive amount of research has brought about major breakthroughs in the electronic and optical properties of 2D materials. This in turn has generated considerable interest in novel device applications. With the polymorphic structural features of 2D-TMDs, this class of materials can exhibit both semiconducting and metallic (quasi-metallic) properties in their respective phases. This polymorphic property further increases the interest in 2D-TMDs both in fundamental research and for their potential utilization in novel high-performance device applications. In this review, we highlight the unique structural properties of few-layer and monolayer TMDs in the metallic 1T- and quasi-metallic 1T′-phases, and how these phases dictate their electronic and optical properties. An overview of the semiconducting-to-(quasi)-metallic phase transition of 2D-TMD systems will be covered along with a discussion on the phase transition mechanisms. The current development in the applications of (quasi)-metallic 2D-TMDs will be presented ranging from high-performance electronic and optoelectronic devices to energy storage, catalysis, piezoelectric and thermoelectric devices, and topological insulator and neuromorphic computing applications. We conclude our review by highlighting the challenges confronting the utilization of TMD-based systems and projecting the future developmental trends with an outlook of the progress needed to propel this exciting field forward. [ABSTRACT FROM AUTHOR]

The phosphate content in water is crucial to all forms of life. Excessive phosphate in water can cause the excessive growth of algae and lower the oxygen content in water, which is a danger to our environment. However, most conventional methods for phosphate detection are time-consuming and instrument-dependent. In this work, three Cu-based metal–organic framework nanomaterials (Cu-MOF(1), Cu-MOF(2), Cu-MOF(3)) were synthesized. And it was found that the obtained three nanomaterials all exhibited peroxidase-like activities. Cu-MOF catalyzed color reaction can be inhibited in the presence of phosphate, and a colorimetric assay is constructed for the determination of phosphate by taking Cu-MOF(3) as an example. Good linearity existed between the absorbance of the Cu–MOF/TMB–H2O2 system at 652 nm and phosphate concentration from 0.05 μM to 5 μM, with the limit of detection down to 20 nM according to the S/N = 3 rule. Besides, the practicality of our assay was also certified by sensing PO43− in local river water samples. [ABSTRACT FROM AUTHOR]

Herein a facile and versatile hydrothermal method has been developed to construct a polypyrrole-derived carbon nanotube (PCN), MoS2 nanosheets and a carbon shell integrated sandwich-like heterostructure (PCN@MoS2@C). This heterostructure shows excellent performance in the hydrogen evolution reaction (HER) over a wide pH range. The results indicate that the porous carbon shell coated heterostructure provides MoS2 nanosheets with sufficient conductivity, increased number of active sites, and strong structural stability, and thus boosts its HER performance. [ABSTRACT FROM AUTHOR]

Syngas, as a necessary feedstock dependent on non-renewable fossil fuels, is a mixture of CO and H2, which could be prepared by a renewable strategy via electrochemical CO2 reduction in water electrolyte solutions. Herein, beaded Au@Co3O4 nanowire arrays (denoted as Au@Co3O4 NAs) were obtained by immersion in HAuCl4 solution with Co3O4 nanowire arrays. The Au@Co3O4 NAs exhibited outstanding electrochemical performance of producing syngas via tuning from 1 : 1 to 4 : 1 with controlling voltage. In addition, the Au@Co3O4 NAs showed better catalytic performance for the oxygen evolution reaction with an overpotential of 320 mV at a current density of 50 mA cm−2, along with a small Tafel slope of 75 mV dec−1 in 1 M KOH solution. The electrochemical performance of Au@Co3O4 NAs is obviously superior to Co3O4 NAs, which will open up a viable strategy for the design and fabrication of a bi-functional electrocatalyst for the overall reaction (CO2 + H2O → CO + H2 + O2). [ABSTRACT FROM AUTHOR]

We fabricate a ferroelectric field effect transistor (FeFET) based on a semiconducting vanadium dioxide (VO2) nanowire (NW), and we investigate its electron transport characteristics modulated by the ferroelectric effects. The transistor consists of a single VO2 NW as the channel and a ferroelectric Pb(Zr0.52Ti0.48)O3 (PZT) thin film as the dielectric gate. The conductance of the VO2 NW channel is found to be feasibly modulated by the ferroelectric gate with an 85% resistance change under the gate voltage of 18 V (at an applied field of about 0.75 MV cm−1). The electron transport property of the device can be controlled by the remnant polarization of the PZT layer due to the nonvolatile property of the ferroelectric gate, with an off-field change of channel resistance up to 50%. Moreover, multiple resistive states can be achieved by sweeping gate voltage across the device appropriately. These results demonstrate that ferroelectric gate modulation is an efficient tool to regulate the electron transport properties of the VO2 NW, and the VO2-NW-FeFET has potential applications in nonvolatile and low-power consumption devices. [ABSTRACT FROM AUTHOR]

A titanium-polyoxomolybdate K6(H3O)8[{PMo9O34TiO}2]·32H2O (1) was successfully synthesized and structurally characterized. It is an unprecedented instance that the titanium-containing polyoxomolybdate is water-soluble and was synthesized by using a conventional aqueous solution method. The Ti4+ ions exist in an unusual coordination mode. Besides, compound 1 as a wide band gap semiconductor showed evident photocatalytic activity for the oxidation of benzaldehyde into benzoic acid. [ABSTRACT FROM AUTHOR]

A dehydroxylative Csp3–N coupling reaction assisted by triphenylphosphine has been developed through electrochemical oxidation. The reaction proceeds via anodic oxidation of triphenylphosphine to generate its corresponding radical cation, followed by reacting with hydroxyl groups to form alkoxy triphenylphosphonium ions, which are trapped by azoles or amides to construct C–N bonds. This method provides an efficient electrochemical strategy of activating hydroxyl groups to form C–N bonds under mild conditions. [ABSTRACT FROM AUTHOR]

In the present study, four copper-based metal–organic frameworks were facilely prepared to study the effects of the substituent groups of the ligand on the enzyme-like properties of these frameworks. It was found that all of them were capable of catalyzing the reaction between 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2; this demonstrated their enzyme-like properties. Moreover, the enzyme-like catalytic properties of all the Cu-MOFs obtained herein were studied in detail. Interestingly, the results indicate that the four Cu-MOFs should be addressed as different enzyme mimics although the chemical structures of their ligands are quite similar. Among these four MOFs, the Cu-MOF with the –NO2 group (Cu-MOF (ii)) exhibits highest catalytic activity at neutral pH, which would be beneficial for its application in real biological samples. Moreover, its catalytic activity should be ascribed to the generation of oxygen induced by Cu-MOF (ii)-catalyzed H2O2 decomposition; this accordingly indicates that this MOF should be called a catalase mimic. Under optimized conditions, the Cu-MOF (ii) was applied to develop a (GSH) colorimetric assay for glutathione (GSH). In addition, GSH detection in serum was performed, and satisfactory results were obtained. Therefore, a simple, sensitive and selective colorimetric assay based on the MOF catalase mimic for the detection of GSH was developed. [ABSTRACT FROM AUTHOR]

Nanomaterial-based artificial enzymes (nanozymes), as an emerging generation of artificial enzymes, have received extensive attention in recent years owing to their striking merits. In this study, the obtained Co3O4 nanocrystals exhibited catalase-like activity and could catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2, and a clear absorption peak at 652 nm can be observed. It was verified that the catalytic activity for the oxidation of TMB originated from the oxygen, which is generated by Co3O4 catalyzed H2O2 decomposition. Upon addition of glutathione (GSH), the catalytic ability of the Co3O4 nanocrystals was inhibited. And, the changes of absorbance at 652 nm could be utilized to quantify the concentration of GSH. Under the optimized conditions, the proposed assay showed good linear relationships and a low detection limit towards GSH. Moreover, the Co3O4 nanocrystals had excellent stability and can maintain the catalytic activity for a long time. Thus, a simple, sensitive and selective nanozyme-based biosensor was developed for the colorimetric detection of GSH. [ABSTRACT FROM AUTHOR]

The preparation of low-cost and efficient bifunctional catalysts towards water splitting is essential for the production of clean H2 energy. Herein, a hierarchical Co3O4-decorated CuO–Cu2O nanorod core–shell structure was in situ grown on a Cu foam (denoted as CuOx@Co3O4 NRs/CF) and investigated as a bifunctional catalyst for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline solution. Benefiting from its large electrochemical surface area and the synergetic effects between the CuOx core and Co3O4 shell, CuOx@Co3O4 NRs/CF exhibited considerable catalytic activity, which resulted in a small overpotential of 240 mV for the OER and 242 mV for the HER at a current density of 50 mA cm−2, along with low Tafel slopes of 46 and 61 mV dec−1, respectively. Remarkably, CuOx@Co3O4 NRs/CF could continuously produce O2 or H2 for at least 24 h with negligible decline in catalytic activity, and it gave rise to high faradaic efficiencies of 99.7% and 96.4% for the OER and HER, respectively. The electrochemical performance of CuOx@Co3O4 NRs/CF was dramatically improved as compared to those of its CuOx NRs/CF counterpart and also most reported Cu-based water splitting electrocatalysts. [ABSTRACT FROM AUTHOR]

As an important strongly correlated electron material, VO2 undergoes a metal–insulator transition (MIT) accompanied by a huge change of several orders of magnitude in conductance and transmittance. The MIT behavior can be controlled by low-dimensional structures (LDSs) and the interaction between LDSs and substrates. Consequently, fabricating the LDSs and understanding the phase transition behaviors have great significance for the investigation of fundamental properties and applications. Using the pulsed laser deposition technique, we fabricate abundant LDSs (i.e., from zero-dimensional nanodots, one-dimensional nanowires, nanobelts and nanorods to two-dimensional nanoplatelets and ultra-thin films, and zero-/one-/two-dimensional mixed structures), and investigate the controllability of each deposition factor on the growth of the LDSs. TEM results confirm the high crystallinity of the as-synthesized LDSs. AFM results and ab initio calculations demonstrate the great influence of substrates on the growth orientation of the LDSs. More importantly, we systematically investigate the phase transition characteristics of the LDSs by temperature-dependent Raman spectroscopy and XRD. The results clearly reveal the structural dependence of the phase transition features due to the delicate effects of substrates and structures. Our technique provides a rapid, controllable and easy method for fabricating VO2 LDSs, which can lead to a deeper understanding of the electrical, optical, and magnetic properties and potential applications of VO2. [ABSTRACT FROM AUTHOR]

The development of iridium complexes as potent anticancer agents has received increasing attention in recent years. In this study, four cyclometalated Ir(iii) complexes with good photophysical properties and potent anticancer activity have been synthesized and characterized. They are taken up by human lung adenocarcinoma A549 cells very quickly and specifically target mitochondria. Mechanism studies reveal that one of them, namely IrM2, induces paraptosis accompanied by excessive mitochondria-derived cytoplasmic vacuoles. Meanwhile, IrM2 affects the ubiquitin–proteasome system (UPS) and mitogen-activated protein kinase (MAPK) signaling pathways. Furthermore, IrM2 rapidly induces a series of mitochondria-related dysfunctional events, including the loss of mitochondrial membrane potential, cellular ATP depletion, mitochondrial respiration inhibition and reactive oxygen species (ROS) elevation. The rapid loss of mitochondrial functions, elevation of ROS and impairment of the UPS induced by IrM2 lead to the collapse of mitochondria and the subsequent cytoplasmic vacuolation before the cells are ready to start the mechanisms of apoptosis and/or autophagy. Among the ROS, superoxide anion radicals play a critical role in IrM2-mediated cell death. In vivo studies reveal that IrM2 can significantly inhibit tumor growth in a mouse model. This work gives useful insights into the design and anticancer mechanisms of new metal-based anticancer agents. [ABSTRACT FROM AUTHOR]

The self-assembly behavior of quaterrylene (QR) molecules on Ag(111) surfaces has been investigated by scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. It is found that the QR molecules are highly mobile on the Ag(111) surface at 78 K. No ordered assembled structure is formed on the surface with a sub-monolayer coverage up to 0.8 monolayer due to the intermolecular repulsive interactions, whereas ordered molecular structures are observed at one monolayer coverage. According to our DFT calculations, charge transfer occurs between the substrate and the adsorbed QR molecule. As a result, out-of-plane dipoles appear at the interface, which are ascribed to the repulsive dipole–dipole interactions between the QR molecules. Furthermore, due to the planar geometry, the QR molecules exhibit relatively low diffusion barriers on Ag(111). By applying a voltage pulse between the tunneling gap, immobilization and aggregation of QR molecules take place, resulting in the formation of a triangle-shaped trimer. Our work demonstrates the ability of manipulating intermolecular repulsive and attractive interactions at the single molecular level. [ABSTRACT FROM AUTHOR]

A new series of uranium coordination polymers have been hydrothermally synthesized by using 1,4-naphthalene dicarboxylic acid (H2NDC), namely, (H3O)2[(UO2)2(NDC)3]·H2O (1), (H2-bpp)[(UO2)2(NDC)3]·EtOH·5H2O (2), (H2-bpe)2/2[(UO2)2(NDC)3]·EtOH (3), (H2-bpp)[(UO2)2(NDC)3]·5H2O (4), (H2-bpp)[(UO2)(HNDC)(NDC)]2·2H2O (5), and (H2-bpy)[(UO2)(NDC)2] (6) [bpp = 1,3-di(4-pyridyl) propane, bpe = 4,4′-vinylenedipyridine, bpy = 4,4′-bipyridine]. Single-crystal X-ray diffraction demonstrates that complex 1 represents the uranyl-organic polycatenated framework derived from a simple two-dimensional honeycomb grid network structure via a H2NDC linker. Complexes 2–4 contain the dinuclear motifs of the two UO7 pentagonal and one UO8 hexagonal bipyramids which are linked by NDC2− anions creating a (UO2)4(NDC)2 unit, and further extend to a 2D layer through NDC2− anions. Complex 5 displays a 1D zigzag double chain structure, in which the carboxylate groups of the NDC2− anions adopt a chelate mode and further extends to a 2D framework via hydrogen bonds. The 1D structure of complex 6 is similar to the zigzag chain of complex 5. In addition, powder X-ray diffraction, elemental analysis, IR, thermal stability and luminescence properties of all complexes have also been investigated in this paper. The photocatalytic properties of the six complexes for the degradation of tetracycline hydrochloride (TC) under UV irradiation have been examined. Moreover, density functional theory (DFT) calculations were carried out to explore the electronic structural and bonding properties of the uranyl complexes 1–6. [ABSTRACT FROM AUTHOR]

The nsucleation effects of isomorphic poly(butylene succinate-co-butylene fumarate)s (PBSFs) on poly(butylene succinate) (PBS) were investigated using differential scanning calorimetry (DSC) and polarized optical microscopy (POM). When the content of PBSF is fixed at 2.0 wt% in the PBSF/PBS blends, the nucleation efficiency of PBSF is related to the BF molar ratio in PBSF. Nucleation efficiency is not observed when the molar ratio of BF is ≤5%; the nucleation efficiency is weak when the molar ratio of BF is between 10% and 30% and the nucleation efficiency is strong when the molar ratio of BF is ≥40%. In fixing the nucleating agent as PBSF-5 (the BF molar ratio of PBSF is 5%), the nucleation efficiency of PBSF-5 is related to its content in the PBSF-5/PBS blends. Nucleation efficiency is not observed when the content of PBSF-5 is ≤2.0 wt% and the nucleation efficiency strengthens dramatically when the content of PBSF-5 is ≥5.0 wt%. POM images reveal the changes of PBS ring-banded spherulites in the PBSF/PBS blends. The band spacing of PBS in the PBSF/PBS blends decreases with the increase of the BF molar ratio of PBSF or the content of PBSF-5. The cell parameters of the PBSF nucleating agent are important in the formation of PBS ring-banded spherulites. No PBS ring-banded spherulite forms when the BF molar ratio of PBSF is ≥40%. In the PBSF-5/PBS blends, the crystallization temperature range of the ring-banded spherulite formation gradually narrows when the content of PBSF-5 is ≥5.0 wt%. In this work, clarifying the slight structure difference of isomorphic PBSFs on the epitaxial nucleation and the formation of PBS ring-banded spherulites is advantageous. [ABSTRACT FROM AUTHOR]

Dye sensitizers play an important role in dye-sensitized solar cells (DSSCs). As a promising strategy for the design of novel porphyrin sensitizers, the asymmetric modification of the porphyrin ring to meso-link porphyrin sensitizer has emerged in recent years, which can improve the light-harvesting properties and enhance the electron distribution. In this work, in order to reveal the essence of the effect of unsymmetrical substitution on the performance of β-link porphyrin dyes in DSSCs, four kinds of common β-link porphyrin dyes with different structures are calculated by using density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The electronic structures and optical properties of these studied dyes in dimethylformamide (DMF) are also investigated. The key parameters of the short-circuit current density (Jsc), including light harvesting efficiency (LHE), electron injection driving force (ΔGinject), and intra-molecular charge transfer (ICT) are discussed in detail. In addition, the periodic DFT calculations in the dye–TiO2 systems are also employed to investigate the geometrical and electronic injection process of the different connection types of these studied dyes adsorbed on the periodic TiO2 model with an exposed anatase (101) surface. We expect the present study would deepen the understanding of the alternative function of unsymmetrical substitution and may contribute to future DSSC design. [ABSTRACT FROM AUTHOR]

Triphenylmethanol (TPOH) is a non-fluorescent compound. Interestingly, after UV irradiation at 254 nm, TPOH showed a strong blue fluorescence on a solid surface. Moreover, the fluorescence can be quenched by UV irradiation at 365 nm, making the photoactivatable fluorescence reversible. TPOH is thus applied for rewritable photopatterning tuned by UV light. [ABSTRACT FROM AUTHOR]

Immobilization of earth-abundant water oxidation catalysts (WOCs) on carbon supports to produce functional electrodes for electrochemical water splitting is a crucial approach for future clean energy production. Herein we report the non-covalent immobilization of a pyrene-bearing cobalt(ii) Schiff base complex (2) on the surface of multiwalled carbon nanotubes (MWCNTs) to form a hybrid anode for electrocatalytic water oxidation. The 2/MWCNT anode displayed excellent catalytic activity and durability in neutral aqueous solution, and a catalytic current density of 1.0 mA cm−2 was achieved at 1.15 V vs. the normal hydrogen electrode (NHE), corresponding to a low overpotential of 330 mV. A Tafel slope of 96 mV per decade was obtained. The Faradaic efficiency of oxygen evolution was more than 90% by bulk electrolysis measurement. After bulk electrolysis, the hybrid anode characterization using X-ray photoelectron spectroscopy (XPS) confirmed that complex 2 decomposed to form heterogeneous cobalt hydroxides and the cobalt hydroxides should be true catalytic active species, which are responsible for electrocatalytic oxygen evolution. [ABSTRACT FROM AUTHOR]

Many phosphorescent iridium complexes are potent candidates as photodynamic therapeutic agents. In this work, a series of mixed-ligand phosphorescent iridium complexes (Ir1: [Ir(L1)(bpy)Cl](PF6)2; Ir2: [Ir(L1)(ppy)Cl](PF6); Ir3: [Ir(L2)(bpy)Cl](PF6)2; Ir4: [Ir(L2)(ppy)Cl](PF6). L1 = 2,6-bis(2-benzimidazolyl)pyridine; bpy = 2,2′-bipyridine; L2 = 2,6-bis(1-methyl-benzimidazol-2-yl)pyridine; ppy = 2-phenylpyridine) have been synthesized and characterized. These complexes display high luminescence quantum yields and long phosphorescence lifetimes. All the complexes are resistant to hydrolysis in aqueous solutions, and can produce singlet oxygen (1O2) effectively upon irradiation. Ir1 and Ir2 show pH-sensitive emission properties. Interestingly, higher cellular uptake efficiency is observed for Ir2 and Ir4 with the cyclometalated ppy ligand in human lung adenocarcinoma A549 cells. Ir2 with pH-sensitive emission properties can selectively image lysosomes, and Ir4 can specifically target mitochondria. Both Ir2 and Ir4 exhibit potent photodynamic therapy (PDT) effects, with Ir2 displaying a higher phototoxicity index (PI) especially in A549 cells (PI ＞ 54). Mechanism studies indicate that Ir2 and Ir4 can induce apoptosis through reactive oxygen species (ROS) generation and caspase activation upon visible light (425 nm) irradiation. As expected, Ir2 can damage lysosomes more effectively with a pH-sensitive singlet oxygen (1O2) yield, while Ir4 tends to impair mitochondrial function. Nevertheless, the practical application of Ir2 and Ir4 for PDT may be limited to superficial tumors due to the short excitation wavelength (425 nm). Our study gives insights into the design and anticancer mechanisms of new metal-based PDT anticancer agents. [ABSTRACT FROM AUTHOR]

Both electrodes and substrates are factors of great significance for the performance of ferroelectric tunnel junctions (FTJs) in designing functional nanodevices. To provide a comprehensive view on the polarization stability in FTJs due to the effects of an electrode and a substrate misfit strain, in this work we calculated more than 1000 FTJ structures by utilizing an ab initio density functional theory (DFT) method, via changing the symmetry of the FTJ structure (i.e., both asymmetric and symmetric FTJs), electrodes (including Au, Ag, Cu, Pt, Co, Fe, and SrRuO3), barrier thickness (ranging from 2 to 10 unit cells), polarization direction (both positive and negative polarizations) and epitaxial strain (i.e., −3%, −2.5%, −2%, −1.5% and −1%) as variables. This shows that the FTJs can exhibit quite diverse polarization bi-stability due to the combined effect of the electrode and strain control, which indicates diverse performance of the FTJs modulated by the electrode and strain. In particular, the polarization-mediated electrostatic potential in the barriers with different electrodes forecasts an electrode-tailored tunnel electroresistance effect. Our study provides guidance on the practical applications of FTJs with regard to the selection of electrodes and substrates. [ABSTRACT FROM AUTHOR]

Azurin (Az) has been considered as the research hotspot in molecular electronics, as well as a promising material for building functional devices on the molecular scale because of its special electrical properties and force-dependent conductance effects. Here we carry out an in-depth investigation combined with molecular scale experiments, molecular dynamics simulations, first-principles calculations and theoretical models to reveal the dynamic conductance response of the Az monolayer under cyclic mechanical loading. Experimentally, the conductance of the Az monolayer under continuous cyclic loads was recorded using a conductive atomic force microscope. Our results demonstrate the strong nonlinear force-dependence and significant time-delayed characteristics, which distinctly differ from the results obtained under stepwise loading. It is also found that the period and amplitude of cyclic loads have a great impact on the magnitude, peak value and change rate of the current. The regular dynamic response of the Az conductance under mechanical force looks like a type of memristive behavior, which is defined as mechanics-modulated memristive behavior in this work. In order to verify these peculiar experimental results, we employed both molecular dynamics simulations and first-principles calculations to analyze the structural deformation and molecular orbitals of Az under cyclic loads. A phenomenological model is also established to explain experimental findings and further illustrate mechanics-modulated memristive behavior. [ABSTRACT FROM AUTHOR]