Photoluminescence Enhancement of 0D Organic-Inorganic Metal Halides via Aggregation-Induced Emission and Halide Substitution.

0D organic-inorganic metal halides (OIMHs) provide unprecedented versatility in structures and photoluminescence properties. Here, a series of bluish-white emissive 0D OIMHs, (TPE-TPP)2Sb2BrxCl8-x (x = 1.16 to 8), are prepared by assembling the 1-triphenylphosphonium-4-(1,2,2-triphenylethenyl)benzene cation (TPE-TPP)+ with antimony halides anions. Based on experimental characterizations and theoretical calculations, the emission of the 0D OIMHs are attributed to the fluorescence of the organic cations with aggregation-induced emission (AIE) properties. The 0D structure minimized the molecular motion and intermolecular interactions between (TPE-TPP)+ cations, effectively suppressing the non-radiative recombination processes. Consequently, the photoluminescence quantum efficiency (PLQE) of (TPE-TPP)2Sb2Br1.16Cl6.84 is significantly enhanced to 55.4% as compared to the organic salt (TPE-TPP)Br (20.5%). The PLQE of (TPE-TPP)2Sb2BrxCl8-x can also be readily manipulated by halide substitution, due to the competitive processes between non-radiative recombination on the inorganic moiety and the energy transfer from inorganic to organic. In addition, electrically driven light-emitting diodes (LEDs) are fabricated based on (TPE-TPP)2Sb2Br1.16Cl6.84 emitter, which exhibited bluish-white emission with a maximum external quantum efficiency (EQE) of 1.1% and luminance of 335 cd m-2. This is the first report of electrically driven LED based on 0D OIMH with bluish-white emission.

Lattice-Disordered High-Entropy Alloy Engineered by Thermal Dezincification for Improved Catalytic Hydrogen Evolution Reaction.

A disordered crystal structure is an asymmetrical atomic lattice resulting from the missing atoms (vacancies) or the lattice misarrangement in a solid-state material. It has been widely proven to improve the electrocatalytic hydrogen evolution reaction (HER) process. In the present work, due to the special physical properties (the low evaporation temperature of below 900 °C), Zn is utilized as a sacrificial component to create senary PtIrNiCoFeZn high-entropy alloy (HEA) with highly disordered lattices. The structure of the lattice-disordered PtIrNiCoFeZn HEA is characterized by the thermal diffusion scattering (TDS) in transmission electron microscope. Density functional theory calculations reveal that lattice disorder not only accelerates both the Volmer step and Tafel step during the HER process but also optimizes the intensity and distribution of projected density of states near the Fermi energy after the H2O and H adsorption. Anomalously high alkaline HER activity and stability are proven by experimental measurements. This work introduces a novel approach to preparing irregular lattices offering highly efficient HEA and a TDS characterization method to reveal the disordered lattice in materials. It provides a new route toward exploring and developing the catalytic activities of materials with asymmetrically disordered lattices.

Exploring the effects and mechanism of peony pollen in treating benign prostatic hyperplasia.

Paeonia suffruticosa is widely cultivated globally due to its medicinal and ornamental value. Peony pollen (PP) is commonly used in Chinese folk medicine to make tea to treat benign prostatic hyperplasia (BPH), but its molecular mechanism against BPH is yet to be comprehended. The objective of this research was to experimentally verify the effect of PP in the treatment of BPH and to preliminarily reveal its mechanism of action on BPH using network pharmacology methods. The results revealed that PP could decrease prostate volume and prostate index, serum testosterone (T), dihydrotestosterone (DHT), and estradiol (E2) levels. Moreover, it could improve prostate tissue structure in BPH model animals as well. Additionally, database searches and disease target matching revealed 81 compounds in PP. Of these, 3, 7, 8, 2'-tetrahydroxyflavone, Chrysin, Wogonin, Limocitrin, and Sexangularetin were the top five compounds associated with the therapeutic effects of BPH. Furthermore, 177 therapeutic targets for BPH were retrieved from databases of Swiss Target, DisGeNET, Drugbank, Genecards, OMIM, TTD, and Uniprot. In contrast, core targets AKT1, EGFR, IL6, TNF, and VEGFA were obtained by PPI network diagram. Molecular docking also showed that the main efficacy components and potential core targets in PP had good binding capacity. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomics (KEGG) analysis established that the effect of PP in BPH therapy was mainly through regulating the expression levels of protein kinase B on phosphatidylinositol 3-kinase and phosphatidylinositol 3-kinase-protein kinase B pathways. Additionally, Western blot experiments also exhibited a significant elevation in the activated PI3K and AKT proteins in the model (Mod) group relative to the control (Con) group, and the expression of these activated proteins was significantly reduced after PP administration. In summary, this research provides a scientific basis for employing PP to treat BPH, preliminarily reveals its mechanism of action and potential targets, and lays the foundation for further research and development.

Self-Reconstructed Spinel Surface Structure Enabling the Long-Term Stable Hydrogen Evolution Reaction/Oxygen Evolution Reaction Efficiency of FeCoNiRu High-Entropy Alloyed Electrocatalyst.

High catalytic efficiency and long-term stability are two main components for the performance assessment of an electrocatalyst. Previous attention has been paid more to efficiency other than stability. The present work is focused on the study of the stability processed on the FeCoNiRu high-entropy alloy (HEA) in correlation with its catalytic efficiency. This catalyst has demonstrated not only performing the simultaneous hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) with high efficiency but also sustaining long-term stability upon HER and OER. The study reveals that the outstanding stability is attributed to the spinel oxide surface layer developed during evolution reactions. The spinel structure preserves the active sites that are inherited from the HEA's intrinsic structure. This work will provide an insightful direction/pathway for the design and manufacturing activities of other metallic electrocatalysts and a benchmark for the assessment of their efficiency-stability relationship.

A Review of Cu-Ni-Sn Alloys: Processing, Microstructure, Properties, and Developing Trends.

Cu-Ni-Sn alloys have been widely used in the aerospace industry, the electronics industry, and other fields due to their excellent electrical and thermal conductivity, high strength, corrosion and wear resistance, etc., which make Cu-15Ni-8Sn alloys the perfect alternative to Cu-Be alloys. This paper begins with how Cu-Ni-Sn alloys are prepared. Then, the microstructural features, especially the precipitation order of each phase, are described. In addition, the influence of alloying elements, such as Si, Ti, and Nb, on its microstructure and properties is discussed. Finally, the effects of plastic deformation and heat treatment on Cu-Ni-Sn alloys are discussed. This review is able to provide insight into the development of novel Cu-Ni-Sn alloys with a high performance.

Visual Identification of Mobile App GUI Elements for Automated Robotic Testing.

Automated robotic testing is an emerging testing approach for mobile apps that can afford complete black-box testing. Compared with other automated testing approaches, automatic robotic testing can reduce the dependence on the internal information of apps. However, capturing GUI element information accurately and effectively from a black-box perspective is a critical issue in robotic testing. This study introduces object detection technology to achieve the visual identification of mobile app GUI elements. First, we consider the requirements of test implementation, the feasibility of visual identification, and the external image features of GUI comprehensively to complete the reasonable classification of GUI elements. Subsequently, we constructed and optimized an object detection dataset for the mobile app GUI. Finally, we implement the identification of GUI elements based on the YOLOv3 model and evaluate the effectiveness of the results. This work can serve as the basis for vision-driven robotic testing for mobile apps and presents a universal approach that is not restricted by platforms to identify mobile app GUI elements.

Synergistic effects of oxidation, coagulation and adsorption in the integrated fenton-based process for wastewater treatment: A review.

Fenton process is the most popular for wastewater treatment among all available advanced oxidation processes (AOPs). Numerous endeavors have been devoted to improving the oxidation efficiency of Fenton reaction in terms of promoting ·OH generation, accelerating iron redox cycle and extending applicable pH range. However, in addition to oxidation, coagulation and adsorption also simultaneously occur in the Fenton process, which play important role in the removal of pollutants. Rapid progress has revealed the synergistic effects of oxidation, coagulation and adsorption in the Fenton process, providing new ideas for the treatment of complex and refractory wastewater. Based on available studies, this review is the first to systematically summarize the research progress regarding the synergistic effects of oxidation, coagulation and adsorption in the integrated Fenton-based processes for wastewater treatment. The involved mechanism of the synergistic effects in different Fenton processes (homogeneous Fenton, heterogeneous Fenton and physical field-assistant Fenton coupling process) are critically reviewed. Furthermore, special attention has been paid to the representative applications of the synergistic effects in wastewater treatment (such as industrial organic wastewater, landfill leachate and heavy metal-organic complexes, etc.), particularly focusing on the operation parameters and removal performance. Finally, a conclusion of the review and subsequently, perspectives are given for possible research directions. We believe this review can provide useful information for researchers and end-users involved in the development and application of the Fenton process in wastewater treatment.

The optoelectronic properties improvement of double perovskites Cs2SnI6 by anionic doping (F-).

Tin-based perovskite material is the best choice to replace heavy metal element lead during the last several years. Cs2SnI6 with Sn4+ is a fascinating optoelectronic material, which is a more air-stable composite cesium tin halide peroxide variant from CsSnI3. However, the optoelectronic performance between N and P type of Cs2SnI6 varies considerably. Herein, we synthesized uniform Cs2SnI6 by modified two-step method, which thermal evaporated CsI firstly, and followed annealing in the SnI4 and I2 vapor at 150 °C resulted in uniform Cs2SnI6 films. SnF4 is used as a dopant source to improve the optoelectronic properties of Cs2SnI6 films. Results indicate that good crystallinity was obtained for all films and the doped films underwent a crystalline plane meritocracy transition. The doped films had a flat, non-porous morphology with large grains. The high transmittance of the doped films in the infrared region led to the avoidance of self-generated thermal decomposition. With the help of F-, the films became more conductive and had higher carrier mobility. DFT calculations showed that doping with F reduced the surface energy of (004), resulted in a preferred orientation transition in the crystal of Cs2SnI6. Fluorine doped double layer perovskite materials would have a broader application prospect.

Bufalin induces mitochondrial dysfunction and promotes apoptosis of glioma cells by regulating Annexin A2 and DRP1 protein expression.

BACKGROUND: Glioma is a common primary central nervous system tumour, and therapeutic drugs that can effectively improve the survival rate of patients in the clinic are lacking. Bufalin is effective in treating various tumours, but the mechanism by which it promotes the apoptosis of glioma cells is unclear. The aim of this study was to investigate the drug targets of bufalin in glioma cells and to clarify the apoptotic mechanism. METHODS: Cell viability and proliferation were evaluated by CCK-8 and colony formation assays. Then, the cell cycle and apoptosis, intracellular ion homeostasis, oxidative stress levels and mitochondrial damage were assessed after bufalin treatment. DARTS-PAGE technology was employed and LC-MS/MS was performed to explore the drug targets of bufalin in U251 cells. Molecular docking and western blotting were performed to identify potential targets. siRNA targeting Annexin A2 and the DRP1 protein inhibitor Mdivi-1 were used to confirm the targets of bufalin. RESULTS: Bufalin upregulated the expression of cytochrome C, cleaved caspase 3, p-Chk1 and p-p53 proteins to induce U251 cell apoptosis and cycle arrest in the S phase. Bufalin also induced oxidative stress in U251 cells, destroyed intracellular ion homeostasis, and caused mitochondrial damage. The expression of mitochondrial division-/fusion-related proteins in U251 cells was abnormal, the Annexin A2 and DRP1 proteins were translocated from the cytoplasm to mitochondria, and the MFN2 protein was released from mitochondria into the cytoplasm after bufalin treatment, disrupting the mitochondrial division/fusion balance in U251 cells. CONCLUSIONS: Our research indicated that bufalin can cause Annexin A2 and DRP1 oligomerization on the surface of mitochondria and disrupt the mitochondrial division/fusion balance to induce U251 cell apoptosis.

Investigation of bromide removal and bromate minimization of membrane capacitive deionization for drinking water treatment.

The ubiquitous bromide (Br-) poses a challenge to current drinking water treatment schemes due to the formation of brominated disinfection by-products, especially bromate (BrO3-). A cost-effective and energy-efficient technology to remove Br- before disinfection is highly desired. In this work, the application of membrane capacitive deionization (MCDI) for the removal of Br- and BrO3- minimization for drinking water treatment was systematically investigated. Results showed that the removal of Br- by MCDI followed the pseudo-second-order kinetics, in which kinetics was faster at lower Br- concentration. Additionally, Br- displayed a preferential electrosorption over Cl- in MCDI despite the relatively smaller amounts. Due to high removal performance of Br-, 99.49% of BrO3- minimization can be achieved. Moreover, the presence of humic acid (HA) had a negative effect on the removal of Br- and BrO3- minimization. However, Br- could be more preferentially removed than Cl- in the presence of HA due to the weak interaction with HA. Finally, by treating an actual surface water sample, it was found that the removal rate of Br- was 91.80%, and 83.97% of BrO3- minimization can be achieved. BrO3- concentration of effluent meets the control standard. Overall, these results prove the feasibility of MCDI for practical drinking water treatment.

Interfacial Chemical Effects of Amorphous Zinc Oxide/Graphene.

Research on the preparation and performance of graphene composite materials has become a hotspot due to the excellent electrical and mechanical properties of graphene. Among such composite materials, zinc oxide/graphene (ZnO/graphene) composite films are an active research topic. Therefore, in this study, we used the vacuum thermal evaporation technique at different evaporation voltages to fabricate an amorphous ZnO/graphene composite film on a flexible polyethylene terephthalate (PET). The amorphous ZnO/graphene composite film inherited the great transparency of the graphene within the visible spectrum. Moreover, its electrical properties were better than those of pure ZnO but less than those of graphene, which is not consistent with the original theoretical research (wherein the performance of the composite films was better than that of ZnO film and slightly lower than that of graphene). For example, the bulk free charge carrier concentrations of the composite films (0.13, 1.36, and 0.47 × 1018 cm-3 corresponding to composite films with thicknesses of 40, 75, and 160 nm) were remarkably lower than that of the bare graphene (964 × 1018 cm-3) and better than that of the ZnO (0.10 × 1018 cm-3). The underlying mechanism for the abnormal electrical performance was further demonstrated by X-ray photoelectron spectroscopy (XPS) detection and first-principles calculations. The analysis found that chemical bonds were formed between the oxide (O) of amorphous ZnO and the carbon (C) of graphene and that the transfer of the π electrons was restricted by C=O and C-O-C bonds. Given the above, this study further clarifies the mechanism affecting the photoelectric properties of amorphous composite films.

Traditional uses, phytochemistry, and pharmacology of Ailanthus altissima (Mill.) Swingle bark: A comprehensive review.

ETHNOPHARMACOLOGICAL RELEVANCE: The dried bark of Ailanthus altissima (Mill.) Swingle (BAA), commonly designated as "Chunpi" in Chinese, is extensively used as a common traditional medicine in China, Korea, and India. It has been used to treat multiple ailments, including asthma, epilepsy, spermatorrhea, bleeding, and ophthalmic diseases, for thousands of years. AIM OF THE REVIEW: To present a comprehensive and constructive review on the phytochemistry, pharmacology, pharmacokinetics, traditional uses, quality control, and toxicology of BAA; to aid the assessment of the therapeutic potential of BAA; to guide researchers working on the development of novel therapeutic agents. MATERIALS AND METHODS: Information related to BAA (from 1960 to 2020) was retrieved from a wide variety of electronic databases, such as PubMed, Web of Science, China Knowledge Resource Integrated Database, ScienceDirect, SciFinder, and Google Scholar. Additional information and materials were acquired from Chinese Medicine Monographs, the 2020 edition of the Chinese Pharmacopoeia, and several web sources, such as the official website of The Plant List and Flora of China. Additionally, perspectives for future investigations and applications of BAA were extensively explored. RESULTS: Approximately 221 chemical compounds, including alkaloids, quassinoids, phenylpropanoids, triterpenoids, volatile oils, and other compounds, have been isolated and characterized from BAA; among these, the quassinoid ailanthone is the most typical. The crude extracts and active compounds of BAA have been reported to exert a wide range of pharmacological activities, such as antitumor, anti-inflammatory, antiviral, herbicidal, and insecticidal activities. Although BAA is safe when administered at a conventional dose, at higher doses, it exhibits toxicity due to the presence of quassinoids. Thus, more studies are required to evaluate the efficacy and safety of BAA. CONCLUSION: Modern pharmacological studies have revealed that BAA, as a valuable medicinal resource, possesses the potential to treat a wide variety of ailments, especially, cancer and gastrointestinal inflammation. These studies present a wide range of perspectives for the development of new drugs related to BAA. However, only a few traditional uses are associated with the reported pharmacological activities of BAA and have been confirmed by preclinical and clinical studies. Moreover, the pharmacokinetics, toxicology, and quality control of BAA should be considered indispensable research topics.

Strained Ultralong Silver Nanowires for Enhanced Electrocatalytic Oxygen Reduction Reaction in Alkaline Medium.

Many noble metals are efficient catalysts for oxygen reduction reaction (ORR), including silver (Ag). Among all these noble metals, Ag is the most affordable because of its relative abundance. Surface energy has been proven to play a crucial role in the catalytic process, and straining is an effective operation to raise the surface energy over electrocatalysts. In this work, sonication was utilized to induce strain in Ag nanowires (NWs) through lattice deformation. A 0.18 J/m2 improvement of the surface energy around the stacking faults area has been calculated via density functional theory. The diffusion-limiting current density was evaluated and increases by >20% (from -4.98 to -6.00 mA/cm2) after sonication straining. Meanwhile, the onset potential remains almost constant (i.e., 0.95 V vs RHE). The results show that induction of strain has a strong impact on the diffusion-limiting current density and significantly improves the ORR catalytic performance of Ag NWs.

Influence of CMTM8 polymorphisms on lung cancer susceptibility in the Chinese Han population.

BACKGROUND: Lung cancer is the leading cause of cancer-related mortality worldwide and CMTM8 is a potential tumor suppressor gene, which is down-regulated in lung cancer. The objective of this research was to assess the association of CMTM8 genetic polymorphisms with lung cancer risk. METHODS: To evaluate the correlation between CMTM8 polymorphisms and lung cancer risk, Agena MassArray platform was used for genotype determination among 509 lung cancer patients and 506 controls. Multiple genetic models, stratification analysis and Haploview analysis were used by calculating odds ratio (OR) and 95% confidence intervals (CIs). RESULTS: Significant associations were detected between CMTM8 rs6771238 and an increased lung cancer risk in codominant (adjusted OR = 1.57, 95% CI: 1.01-2.42, P = 0.044) and dominant (adjusted OR = 1.54, 95% CI: 1.01-2.36, P = 0.047) models. After sex stratification analysis, we observed that rs6771238 was related to an increased risk of lung squamous cell carcinoma, while rs6771238 was associated with an increased risk of lung adenocarcinoma. Rs9835916 was linked to increased risk of lymph node metastasis in lung cancer patients. CONCLUSION: Our study first reported that CMTM8 polymorphisms were a risk factor for lung cancer, which suggested the potential roles of CMTM8 in the development of lung cancer.

Highly Strained Au Nanoparticles for Improved Electrocatalysis of Ethanol Oxidation Reaction.

Au is an ideal noble metal for use as an electrocatalyst for the ethanol oxidation reaction owing to its high performance-to-cost ratio. The catalyst usually exists as nanoparticles (NPs) for high surface area-to-volume ratio. In the present work, a nontraditional physical approach has been developed to fabricate ultrasmall and homogeneous single-crystalline Au NPs by ion bombardment in a precision ion polishing system. Transmission electron microscopy characterizations show that the Au NPs produced with 5 keV Ar+ are highly strained to form twinned crystals, which accumulate a large amount of surface energy, and this was found to be an underlying reason causing strong catalysis. Electrochemistry tests reveal that in alkaline medium the C1 pathway occurs much more preferentially with the strained Au NPs than the normal Au NPs. The surface area-to-volume ratio is no longer the only factor that affects the performance; instead, surface energy might play a more important role in enhancing the catalytic activities.

Effect of static magnetic field on mold corrosion of printed circuit boards.

Mold has a strong impact on the corrosion behavior of metals, especially under environmental conditions conducive to mold growth. However, the magnetic fields generated by electronic devices have effects on the metal corrosion and mold growth. In this study, a 10 mT static magnetic field (SMF) perpendicular to the surface of samples was applied to study the corrosion of a copper-clad printed circuit board (PCB-Cu) by mold under the SMF. Based on the analysis of the corrosion morphology of the PCB-Cu after a test in the atmosphere and the composition of the corrosion products, the corrosion behavior of mold on the PCB-Cu in the presence or absence of the SMF was revealed. In the absence of a magnetic field, mold formed a spore-centered corrosion pit group on the surface of the PCB-Cu, which was macroscopically characterized by regional uniform corrosion. When a 10 mT SMF was applied, the magnetic field exhibited an inhibitory effect on the growth of mold, which was hindered, and the corrosion of the PCB-Cu surface slowed down.

ß-N-Oxalyl-L-α,ß-diaminopropionic acid from Panax notoginseng plays a major role in the treatment of type 2 diabetic nephropathy.

BACKGROUND: Diabetic nephropathy (DN) is one of the most serious and dangerous chronic complications of diabetes mellitus.Panax notoginseng has been widely used with great efficacy in the long-term treatment of kidney disease. However, the mechanism by which it exerts its effects has not been fully elucidated. AIM: We sought to identify the major components ofPanax notoginseng that are effective in reducing the symptoms of DN in vitro and in vivo. METHODS: Inhibition of cell proliferation and collagen secretion were used to screen the ten most highly concentrated components ofPanax notoginseng. The STZ-induced DN rat model on a high-fat-high-glucose diet was used to investigate the renal protective effect of Panax notoginseng and dencichine and their underlying molecular mechanisms. RESULTS: Among the ten components analysed, dencichine (ß-N-oxalyl-L-α,ß-diaminopropionic acid) was the most protective against DN. Dencichine andPanax notoginseng attenuated glucose and lipid metabolic disorders in STZ-induced DN rats on a high-fat-high-glucose diet. In the untreated DN rats, we observed albuminuria, renal failure, and pathological changes. However, treatment with dencichine and Panax notoginseng alleviated these symptoms. We also observed that dencichine suppressed the expression of TGF-ß1 and Smad2/3, which mediates mesangial cell proliferation and extracellular matrix (ECM) accumulation in the glomerulus, and enhanced the expression of Smad7, the endogenous inhibitor of the TGF-ß1/Smad signalling pathway. CONCLUSION: From these results, we concluded that dencichine is the main compound inPanax notoginseng that is responsible for alleviating renal injury in the experimental DN model. Its mechanism may be related to the reduction of the deposition of ECM in glomeruli and inhibition of the epithelial mesenchymal transformation (EMT) by inhibition of the TGF-ß1/Smad signalling pathway.

Extraordinary catalysis induced by titanium foil cathode plasma for degradation of water pollutant.

The present paper reports a rapid and cost-effective bifunctional approach to the degradation of organic pollutants in the aqueous solution. This in situ hybrid induced photocatalytic method involves the advanced oxidation process, and photocatalytic process induced by ultraviolet radiated from the plasma discharge to improve the degradation efficiency. This powerful plasma allows the organic molecules to be cleaved either in the plasma zone or on the plasma/solution interface through hydrogen abstraction and electron transfer. Four parallel metal foil electrodes (i.e. Ta, Cu, Ti and Au coated Ti), used as cathodes in the two-electrode system, were evaluated in terms of their degradable performance to organic pollutants. It was found that the degradation rates are dependent on the electrical conduction of metal cathodes. During the discharge process, the Ti-based foil produces TiO2 particles, which then act as catalyst in the electrolyte and perform the photocatalytic process along with the plasma discharge process to degrade organic pollutants. It is of particular interest that gold nanoparticles, generated from Au coated Ti foil film during electrode discharging, are less than 5 nm in size and further enhance the TiO2 photocatalytic activity. In fact, this bifunctional plasma discharge process to the degradation of water pollutant provides an insight into more applications such as chemical conversion, water purification and dust pollution.

Fluorine ion induced phase evolution of tin-based perovskite thin films: structure and properties.

To study the effect of fluorine ions on the phase transformation of a tin-based perovskite, CsSnI3-x (F) x films were deposited by using thermal vacuum evaporation from a mixed powder of SnI2, SnF2 and CsI, followed by rapid vacuum annealing. The color evolution, structure, and properties of CsSnI3-x F x films aged in air were observed and analyzed. The results showed that the colors of the films changed from black to yellow, and finally presented as black again over time; the unstable B-γ-CsSnI3-x F x phase transformed into the Y-CsSnI3-x F x phase, which is then recombined into the Cs2SnI6-x F x phase with the generation of SnO2 in air. Fluorine dopant inhibited the oxidation process. The postponement of the phase transformation is due to the stronger bonds between F and Sn than that between I and Sn. The color changing process of the CsSnI3-x F x films slowed that the hole concentrations increased and the resistivities decreased with the increase of the F dopant ratio. With the addition of SnF2, light harvesting within the visible light region was significantly enhanced. Comparison of the optical and electrical properties of the fresh annealed CsSnI3-x F x films showed that the band gaps of the aged films widened, the hole concentrations kept the same order, the hole mobilities reduced and therefore, the resistivities increased. The double layer Cs2SnI6-x F x phase also showed 'p' type semi-conductor properties, which might be due to the incomplete transition of Sn2+ to Sn4+, i.e. Sn2+ provides holes as the acceptor.

Nanostructured CuO/C Hollow Shell@3D Copper Dendrites as a Highly Efficient Electrocatalyst for Oxygen Evolution Reaction.

Adoption of bare metal oxides as catalytic materials shows inferior electrochemical activity because of their poor electrical conductivity. Although synthetic strategies for the employment of conductive substrates are well-established, the rational design and fabrication of hollow metal oxides nanostructures on the robust matrix with a high surface area and conductivity remains challenging. In the present research work, a strategy that transforms a metal-organic framework thin layer into a nanostructured CuO/C hollow shell to coat on the 3D nano-dendritic Cu foams as an electrode was successfully developed. This electrode is claimed to provide an extraordinary electrocatalysis for oxygen evolution reaction (OER) in alkaline media. The hierarchical complex presents fast electronic transmission networks and rich redox sites, leading to the significant enhancement in electrocatalytic OER efficiency. Furthermore, the spherical porous structure and robust architecture facilitate the high-speed diffusion of O2 bubbles in a long-term operation. The results of this study may serve as a reference for the designing of novel class 3D metal/metal oxide hierarchical structures for gas-involved (i.e., O2, H2, and CO2) electrocatalytic applications and beyond.