The photoelectrochemical (PEC) synthesis of hydrogen peroxide (H2O2) on hematite (Fe2O3) is plagued by issues such as poor electrical conductivity and short hole diffusion length, which can result in severe recombination of electron-hole pairs, thereby limiting both the H2O2 yield and Faraday efficiency. To overcome these limitations, this study utilizes the synergistic effect of Ge/Ti in Fe2O3 and constructs a nanoporous Fe2O3 structure via the Kirkendall effect. Through density functional theory (DFT) calculations, sample morphological analysis, and electrochemical analysis, Ti doping plays a critical role in accelerating Fe atom diffusion by regulating oxygen vacancies and improving charge transfer, enabling the Kirkendall effect between Fe in the Ti:FeOOH layer and Ge in the surface GeO2 layer during high-temperature annealing. This process generates internal voids that coalesce into a nanoporous morphology, effectively shortening the hole diffusion length of Fe2O3, thereby inhibiting charge recombination and boosting water oxidation kinetics. The optimized Ge/Ti:Fe2O3 photoanode achieves a H2O2 yield of 0.488 mu mol min- 1 cm- 2 at 1.4 versus the reversible hydrogen electrode (vs. RHE), with a remarkable Faradaic efficiency of 85.6% for the 2-electron WOR. This work presents a promising strategy to address the intrinsically low PEC activity of hematite photoanodes.

Achieving high solar-to-chemical conversion (SCC) efficiency is imperative for the practical application of semiconductors photocatalytic H2O2 production. However, this objective remains significantly challenging due to limitations inherent in conventional systems, including inefficient light harvesting, rapid charge recombination, and mass transfer constraints. To address these bottlenecks, a synergistic "material-system" design is validated. At the material level, ultraviolet-visible, X-ray photoelectron spectroscopy, and time-resolved photoluminescence analyses confirm that the S-pCN/BiVO4 S-scheme heterojunction significantly broadens visible light absorption and facilitates directed charge separation. At the system level, contact angle and kinetic analyses demonstrate that anchoring the catalyst onto a hydrophilic polyurethane-poly (propylene glycol) (HPU-PGG) hydrogel creates a floatable platform with a three-phase interface, enabling direct atmospheric oxygen utilization and superior mass transfer. Furthermore, the system's physical architecture effectively isolates the photocatalyst from the H2O2 product, suppressing undesirable decomposition. Consequently, the S-pCN/BiVO4/HPU-PGG system achieves a high H2O2 yield of 488μmol/L/h under visible light irradiation. This synergistic design achieves an SCC efficiency of 0.85%, which is eight times higher than that of natural photosynthesis.

ABSTRACT The electrochemical CO 2 reduction reaction (CO 2 RR) to ethylene (C 2 H 4 ) is an ideal pathway for closing the carbon cycle. However, single Cu‐based catalysts often have an insufficient supply of CO intermediates and restricted C‐C coupling kinetics, which collectively constrain the C 2 H 4 production efficiency. Additionally, the fabrication of traditional single‐Cu‐based catalyst electrodes typically involves the use of polymer binders to enhance adhesion; however, this often results in high interfacial resistance and impedes mass transport. To address these challenges, this study presents a binder‐free AgNPs/CuNWs tandem catalyst strategy using a gas diffusion electrode (GDE). The uniformly dispersed silver nanoparticles (AgNPs) efficiently generate CO intermediates, providing high concentrations, while the adjacent copper nanowires (CuNWs) act as C‐C coupling sites, reducing the locally generated CO into C 2 H 4 . Electrochemical tests demonstrate that this tandem catalyst exhibits superior catalytic performance, achieving a C 2 H 4 Faradaic efficiency (FE) of 43% at ‐1.2 V (vs. RHE). Furthermore, the catalyst maintained excellent structural integrity and catalytic activity during a 24‐hour stability test. Comparative CO reduction reaction (CORR) experiments confirmed that the AgNPs/CuNWs system follows a tandem catalytic mechanism. This work provides new insights into designing efficient, stable, and binder‐free electrocatalysts for C 2 H 4 production.

The electrochemical CO2 reduction reaction (CO2RR) to ethylene (C2H4) is an ideal pathway for closing the carbon cycle. However, single Cu-based catalysts often have an insufficient supply of CO intermediates and restricted C-C coupling kinetics, which collectively constrain the C2H4 production efficiency. Additionally, the fabrication of traditional single-Cu-based catalyst electrodes typically involves the use of polymer binders to enhance adhesion; however, this often results in high interfacial resistance and impedes mass transport. To address these challenges, this study presents a binder-free AgNPs/CuNWs tandem catalyst strategy using a gas diffusion electrode (GDE). The uniformly dispersed silver nanoparticles (AgNPs) efficiently generate CO intermediates, providing high concentrations, while the adjacent copper nanowires (CuNWs) act as C-C coupling sites, reducing the locally generated CO into C2H4. Electrochemical tests demonstrate that this tandem catalyst exhibits superior catalytic performance, achieving a C2H4 Faradaic efficiency (FE) of 43% at -1.2 V (vs. RHE). Furthermore, the catalyst maintained excellent structural integrity and catalytic activity during a 24-hour stability test. Comparative CO reduction reaction (CORR) experiments confirmed that the AgNPs/CuNWs system follows a tandem catalytic mechanism. This work provides new insights into designing efficient, stable, and binder-free electrocatalysts for C2H4 production.

Colloidal quantum dots (QDs) usually surfer from incomplete ligand coverage due to the steric hinderance of bulky long-chain ligands used in the synthesis stage and ligand desorption during the purification process. In this work, a metal halide ligand-assisted purification (LAP) method is developed for the first time and applied to enhance the luminescence performance of eco-friendly ZnSeTe-based pure-blue QDs synthesized without HF. Compared to the traditional purification (TP) method, the LAP approach is capable of enhancing the photoluminescence quantum efficiency (PLQY) and environmental stability of the QDs without compromising their colloidal stability and solution processability for uniform thin-film fabrication. Among the three zinc halide ligands (ZnCl2, ZnBr2, and ZnI2), ZnCl2-assisted purification achieved the most significant photoluminescence enhancement, increasing the QDs' PLQY from 57% (obtained through TP) to 82%. This improvement is attributed to the fact that the small-sized chloride ligands effectively passivate QD surface defects via binding to undercoordinated surface atoms during purification. The pure-blue light-emitting diode based on the optimal LAP-QDs displayed a 4-fold increase in maximum luminescence intensity and a 1.5-fold enhancement in peak external quantum efficiency compared to that based on the TP-QDs. This study demonstrates a simple yet efficient purification strategy for improving colloidal QD luminescence.

Cu2O is a promising p-type semiconductor for photoelectrochemical (PEC) hydrogen production owing to its suitable band structure and high theoretical photocurrent density. However, its practical application is limited by fast photogenerated carrier recombination and severe photocorrosion. In this work, a NiOx/Cu2O-A/CeO2 sandwich-structured photocathode was fabricated. Based on their electric structure with favorable interfacial band alignment, NiOx and CeO2 play a role as hole transport and electron transport layer to accelerate Cu2O surface carrier separation, respectively. Meanwhile, annealing induces in situ formation of Cu nanoparticles within Cu2O, improving Cu2O bulk electron extraction and carrier separation. CeO2 simultaneously acts as protective coating, suppressing surface recombination and photocorrosion. The optimized NiOx/Cu2O-A/CeO2 photocathode delivers a photocurrent density of 3.1 mA/cm2 at 0 V versus RHE, more than ten times higher than pure Cu2O, with a maximum IPCE of 33.1%. Moreover, it retains 68% of its initial current after 5 h operation, exhibiting markedly improved stability. Electrochemical and optical analyses indicate that the multilayer architecture synergistically modulates surface charge transport, prolongs carrier lifetime, enhances separation and injection efficiencies. This work demonstrates a simple and low-cost strategy for constructing efficient and stable Cu2O-based photocathodes.

In perovskite solar cells, not only does the upper surface of the perovskite active layer affect device performance, but also the perovskite buried interface matters. In this work, we report an effective double-sided treatment strategy for passivating perovskite so as to fabricate efficient n-i-p solar cells with improved stability and negligible hysteresis. The strategy involves the simultaneous application of cyclohexylmethylammonium iodide (CMI) to modify both the upper perovskite/spiro-OMeTAD interface and the buried SnO2/perovskite interface. It is demonstrated that the strategy significantly enhances the photovoltaic efficiency and stability of perovskite solar cells through synergistic dual-interface engineering. The buried-interface CMI promotes three-dimensional (3D) perovskite crystallization while reducing grain boundaries and defects, whereas the surface CMI modification generates two dimensional (2D)-3D perovskite heterostructures that are instrumental in passivating defects and improving carrier extraction at the perovskite/hole transport layer interface. The best-performing device, which underwent the double-sided CMI treatment, achieved a power conversion efficiency of 20.66% with improved stability and negligible hysteresis, substantially superior to those without CMI treatment or with single-sided CMI treatment only. The double-sided synergistic passivation strategy developed in this work offers a simple and effective approach to enhancing the device performance of perovskite solar cells.

Blue quantum dot light-emitting diodes (QLEDs), particularly those emitting pure-blue light in the wavelength range of 450-465 nm, still lag behind their red and green counterparts in terms of efficiency and luminance. In this work, a facile and effective LiCl dual-target treatment strategy, simultaneously engineering both the quantum dot (QD) emissive layer and the hole injection layer (HIL), is proposed for fabricating highly efficient and high-brightness pure-blue QLEDs. The strategy not only optimizes QD surface chemistry and energy level alignment with charge transport layers while mitigating fluorescence quenching at the QD/electron transport layer interface, but also improves the conductivity, light transmittance, and hole injection efficiency of the HIL. The fabricated pure-blue QLED device with the LiCl dual-target treatment (peak wavelength: 461 nm; emission line width: 19 nm) exhibits a maximum luminance of 27,210 cd/m2 and a peak external quantum efficiency of 23.44%, appreciably outperforming the untreated devices and those subjected to single LiCl treatments. To the best of our knowledge, the device surpasses the current state-of-the-art cadmium-based pure-blue QLEDs in terms of efficiency. The feasible fabrication strategy for high-performance pure-blue QLEDs and the mechanistic insights presented herein may advance QD display technologies.

Full solution-processed quantum dot light-emitting diodes (QLEDs) typically suffer from the problem of electron-hole injection imbalance,which severely limits the performance improvement of blue QLEDs devices. The effects of metal halide (LiCl) doping on the morphology,conductivity and light transmittance of poly(ethylenedioxythiophene): polystyrene sulfonate (PEDOT: PSS) films and the device performance of the prepared QLEDs were investigated. The experimental results show that the best effect on the enhancement of blue QLED device performance is achieved when the doping concentration of LiCl is 2%(mass fraction), which is mainly attributed to the enhancement of conductivity and transmittance of LiCl-doped PEDOT:PSS films as well as the improvement of hole injection efficiency in the devices. Compared with the undoped PEDOT:PSS-based QLED devices,the maximum brightness, current efficiency,power efficiency and external quantum efficiency of the LiCl-doped blue QLED devices are increased to 7 451 cd center dot m(-2),1. 38 cd center dot A(-1),0. 89 lm center dot W-1 and 3. 51% from 5 083 cd center dot m(-2),0. 91 cd center dot A(-1), 0. 59 lm center dot W-1 and 2. 31%,respectively. The results show that the use of LiCl-doped PEDOT:PSS hole injection layer is an effective strategy to improve the performance of blue QLEDs.

以硝酸钠溶液作为腐蚀液,通过电化学和紫外辅助电化学相结合的两步法腐蚀GaN薄膜,制备出了多孔阵列结构.采用扫描电子显微镜(SEM)表征了多孔阵列结构的形貌,结果表明多孔GaN阵列结构排列整齐,孔径分布均匀,其平均孔径为24.1 nm,孔隙密度为3.86 × 1010 cm-2,深度为2 μm.利用X射线衍射仪(XRD)和Raman光谱仪表征了多孔GaN阵列的晶体结构,与平面GaN薄膜相比,多孔GaN阵列结构的晶体质量更好,且具有较低的残余应力.使用光致发光(PL)光谱和紫外-可见光(UV-Vis)吸收光谱表征了GaN的光学性能,与平面GaN薄膜相比,多孔GaN阵列结构的光致发光强度和光吸收能力有较大提升.通过电化学工作站对多孔GaN阵列结构的光电性能进行测试,在1.23 V偏压下,多孔GaN阵列结构的光电流是GaN平面结构的约3.36倍,最大光电转化效率ηmax是平面GaN薄膜的约3.5倍.该研究为多孔GaN阵列结构的应用提供了一定的实验数据和理论指导.

两步沉积法中胺盐的传统溶剂异丙醇会对锡基钙钛矿产生严重破坏,因此探索其他溶剂制备锡基钙钛矿非常重要.利用4-甲基-2-戊醇取代异丙醇充当胺盐的溶剂,并在胺盐中添加苯乙基溴化胺(PEABr),通过两步沉积法制备了锡基钙钛矿薄膜及全溶液工艺太阳能电池.实验结果表明,相比于异丙醇,使用4-甲基-2-戊醇作为胺盐溶剂,可降低对锡基钙钛矿的破坏作用,促进锡基钙钛矿结晶成膜,原因可能是该溶剂分子的烷基部分可以增加对羟基的空间位阻.但未添加PEABr时,制备的FASnI3薄膜存在许多针孔,器件光电转换效率(PCE)仅为0.24％;在添加摩尔占比为0.3(n(PEABr)/n(FAI+PEABr)=0.3)的PEABr时,制备的锡基钙钛矿薄膜针孔减少,致密度提高,表面形貌得到改善.利用全溶液工艺制备的基于该薄膜的太阳能电池PCE达到4.15％.该研究有助于促进两步沉积法制备锡基钙钛矿薄膜及其光伏器件的进一步发展.

Quantum dot light-emitting diodes (QLEDs) are considered as the ideal candidate for next-generation displays, solid-state lighting, and optical communication applications. Although the efficiency of QLEDs has been significantly improved to the level comparable to that of organic light-emitting diodes in recent years, simultaneously achieving high efficiency and high brightness still remains challenging for QLEDs. In this work, we report a facile and effective electron-transport-layer interface control strategy of incorporating 3-aminopropyl triethoxysilane (APTES) into a ZnO nanocrystal-solution to enhance charge injection balance and suppress interfacial exciton quenching via in-situ formation of ZnO/organic silica (hereinafter referred to as ZnO/SiO2) quasi core/shell nanoparticles in the solution, enabling red QLEDs to exhibit a maximum luminance intensity of 261,700 cd m- 2, a peak external quantum efficiency (EQE) of 19.0%, and low efficiency roll-off at high luminance (an EQE up to 16.8% remained at a brightness of 200, 000 cd m-2). Our results demonstrate that substituting quasi core/shell-structured ZnO/SiO2 nanoparticles for traditional ZnO nanocrystals as electron transport materials is a simple and effective means of fabricating QLEDs with both high efficiency and high luminance, which is expected to facilitate the development of QLED technology toward practical applications in lighting, displays and optical communication.

相较于红光和绿光量子点发光二极管(QLED),制备高效蓝光QLED仍然具有挑战性.比较研究了有机配体(辛硫醇,OT)、无机配体(ZnCl2)和有机-无机混合配体(OT和ZnCl2)置换原始油酸配体对量子点(QD)的光致和电致发光性能的影响规律及机制.实验结果表明,有机-无机混合配体置换对蓝光QLED的发光性能的提升效果最佳,ZnCl2配体次之,辛硫醇配体最小,这主要归因于三种配体置换后量子点表面缺陷钝化以及量子点价带顶能级上移程度方面的差异.相较于原始油酸配体置换QLED,基于有机-无机混合配体置换量子点蓝光QLED的峰值功率效率和最高外量子效率分别约提高了2.08倍和1.89倍,最高亮度从2 413 cd/m2提高到了6 994 cd/m2.该研究为调控量子点表面化学性质和提高蓝光QLED性能提供了一种有效策略.

Reaction temperature has been demonstrated to play a critical role in the crystallization and quality control of MAPbI3 perovskite films (single cation/halide perovskite; MA: methylamine, CH3NH3), which should also be true for mixed cation/halide perovskite systems. However, there is a lack of direct comparative studies on the effect of reaction temperature on the film quality and cell performance of various perovskite systems. Herein we have systematically investigated the effect of reaction temperature (controlled by changing the temperature of ammonium salt solutions in this work) on film quality and cell performance of single and mixed cation/halide perovskite systems, namely (FAPbI3)1-x(MAPbBr3)x, FAxMA1-xPbI3 and MAPbI3 (FA: formamidine, CH(NH2)2) by means of absorption/photoluminescence spectroscopy, X-ray diffraction, scanning electron microscopy and various electrical measurements. The results show that an appropriate increase in the reaction temperature is favorable for obtaining high-quality perovskite films and improving cell performance, while an excessively high reaction temperature can cause the generation of photovoltaic non-active phase and the reduction of cell performance. In addition, the mixed-cation/halide perovskite systems are more susceptible to reaction temperature relative to the single cation/halide perovskite with respect to phase purity and grain size. The optimal ammonium salt solution temperatures for preparing (FAPbI3)1-x(MAPbBr3)x, FAxMA1-xPbI3 and MAPbI3 films and corresponding solar cells were found to be around 30, 30 and 55 degrees C, respectively, in our two-step deposition process. The (FAPbI3)1-x(MAPbBr3)x based device prepared from the ammonium precursor solution at 30 degrees C delivered the highest efficiency of 18.09%, which can be attributed to the reduced defect density in the perovskite film and the accelerated charge extraction at interfaces. This work highlights the distinct optimal reaction temperatures for different perovskite systems in the two-step deposition process and provides a simple thermodynamic regulation method to improve cell performance.

In order to adjust the band gap of n-ZnO nanorods (NRs)/p-GaN heterojunction and improve its conductivity, a Cu and Ag co-doping ZnO nanorod array has been synthesised on a p-GaN/Al2O3 substrate by a hydrothermal method at low temperature, in addition, investigated the co-doping effect on the morphology, microstructure and electrical/optical properties. Compared with other samples, the average diameter of the co-doped ZnO NRs is larger, and there are fewer NRs per unit area (density). According to X-ray diffraction analysis, the synthesised ZnO NRs had a preferential [001] growth direction and exhibited a hexagonal wurtzite structure. Compared with undoped ZnO NRs, the UV emission peaks of all doped ZnO NRs had a slight red-shift, which may be related to the combined effect of surface resonance and band gap renormalisation effect. Ag+Cu co-doping can also reduce the band gap of the ZnO NRs. The I-V characteristics curve indicates that Ag+Cu co-doping can greatly improve the electrical properties of the heterojunction. This study demonstrates the possibility of ZnO NRs by Ag+Cu co-doping for potential applications in ultraviolet light-emitting diode.

Owing to the COVID-19 outbreak, sterilization of deep-ultraviolet light-emitting diodes (DUV LEDs) has attracted increasing attention. Effectively improving the radiative recombination efficiency and mitigating the efficiency degradation, mainly caused by electron leakage and nonradiative recombination, have also emerged as two of the main issues to be addressed. In this study, a DUV LED epitaxial structure with a novel electron-blocking layer (EBL) is proposed. The DUV LED with a luminescence wavelength of ∼297 nm was formed by the stepwise variation of the Al component. Through the simulation and analysis of its performance parameters, we found that, compared to the conventional EBL structure, this new EBL structure not only reduces the electron leakage to the p-region effectively but also increases the hole injection into the active region, resulting in an increase in carrier concentration in the active region, a two-to-three-fold increase in the radiative recombination rate, and a 58% increase in the internal quantum efficiency, thus alleviating the efficiency droop and achieving a more efficient operation at high current densities.

Semi-polar (10 (1) over bar1) green InGaN light-emitting diodes with different quantum barrier materials were numerically investigated by considering the In composition fluctuation model. For the green light-emitting diode using quaternary Al0.05In0.1Ga0.85N quantum barriers with low Al content, the electric field was reduced, the carrier distribution was appropriately modified, and the efficiency droop was significantly alleviated. In particular, the band pulldown was relieved, and the Fermi levels were flatter, which elevated the electron confinement and decreased the hole injection potential barrier, further promoting hole transport. Moreover, the carrier distribution was more homogeneous and no longer concentrated in the last quantum well, resulting in a reduced nonradiative recombination rate and minimal turn-on voltage. Finally, the internal quantum efficiency was further enhanced by increasing the radiative recombination and thus the efficiency decreased by only 9.1% at a current density of 1000 A/cm(2). The proposed structure using quaternary Al0.05In0.1Ga0.85N with low Al molar fraction as a quantum barrier showed great potential for overcoming the "green gap" problem and application in high-power scenarios. (c) 2022 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

In this paper, polarization intensity as a function of crystallographic orientation is studied by the InGaN/ GaN single quantum well model. The results reveal that the polarization electric field inversion in the semi-polar (10-(1) over bar1) quantum well leads to upward bending of the energy band, and the electron wave function in the quantum well is close to the n-side, which is likely to successfully suppress electron leakage. The simulation of the epitaxial structure of (10-(1) over bar1)-plane InGaN/ GaN multi-quantum-well blue light-emitting diodes (LEDs) demonstrates that LEDs grown on the semi-polar (10-(1) over bar1) plane can elevate the effective blocking barrier of the quantum barrier and suppress electron leakage. Moreover, the (10-(1) over bar1) plane greatly reduces the hole injection barrier, promotes the even distribution of carriers, and reduces Auger recombination probability. Finally, the efficiency droop in (10 1 1) - plane GaN-based LEDs is drastically reduced to 9% at the current density of 300 A/cm(2) compared with 42% efficiency droop in the (0001) plane, and electroluminescence intensity is increased by 48%. The electrostatic field inversion of the ( 10-(1) over bar1)-plane InGaN quantum well is an important reason for its excellent photoelectric properties.

Organic-inorganic hybrid perovskite solar cells (PSCs) have attracted much attention because of their high photoelectric conversion efficiency (PCE) and simple preparation process. At present, one of the major factors limiting the further improvement of PSCs' performance is defects in perovskite active layers. Herein, we report an effective surface post-treatment method for perovskite active layers, which uses potassium bis(fluorosulfonyl) imide (KFSI) to passivate multiple defects, improve photovoltaic performance and reduce the hysteresis. It is demonstrated that not only S=O and S-N bonds but also charged K+ and FSIxe213; ions in KFSI contribute to the passivation of multiple defects in perovskite films via Lewis acid-base interaction and/or forming ionic bonds. After the optimized KFSI treatment, the trap density of the perovskite film decreased from 8.41 x 1015cmxe213; 3 to 3.97 x 1015cmxe213; 3, which significantly suppressed trap-assisted nonradiative recombination of carriers in perovskite films and/or at perovskite/hole transport layer interface. The KFSI treated device achieved a PCE of ~19.00% with less hysteresis, appreciably outperforming the control device (17.22%). At the same time, the performance reproducibility among the fabricated solar cells was remarkably improved. This work provides a facile way to passivate multiple defects in perovskite films and further enhance the performance of perovskite solar cells.