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Acceleration of tungsten doping on vanadium dioxide (VO2) by alkali species
摘要： The monoclinic vanadium dioxide, VO2(M), undergoes reversible phase transition from monoclinic (semiconductor) to tetragonal (metal), which exhibits a good thermochromic property. VOSO4, as a vanadium source, is easy to handle produces VO2(M) under mild condition in the presence of alkali species. In this study, the effects of the additions of NH4HCO3, NH3·H2O, and NaOH on the VO2 crystal formation with/without tungsten doping for thermochromicity were investigated. NaOH, the strongest base of the three, provided the strongest and narrowest x-ray diffraction peak, while NH4HCO3, the weakest base, provided the opposite. Interestingly, for the tungsten doping to adjust the transition temperature, the use of NH4HCO3 was more suitable due to the possibility of a slow crystal frame formation as compared to the use of NaOH.
关键词： Sodium hydroxide,Vanadium dioxide,Ammonium hydrogen carbonate,Ammonium hydroxide,Tungsten doping
更新于2025-09-23 15:22:29
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Beyond 10% efficiency Cu <sub/>2</sub> ZnSnS <sub/>4</sub> solar cells enabled by modifying the heterojunction interface chemistry
摘要： Wide band gap pure sulphide kesterite Cu2ZnSnS4 is a promising environmentally friendly and low-cost photovoltaic material, which has attracted intense research interest. However, the record e?ciency of solar cells based on Cu2ZnSnS4 absorbers just overcame the benchmark 10%, being far from the e?ciency requirement for industrial-scale deployment. Recombination at the heterojunction interface accounts for a large proportion of the performance loss. Here we report a substantial improvement of the Cu2ZnSnS4 solar cell e?ciency to over 10% enabled by modifying the Cu2ZnSnS4/Zn1?xCdxS heterojunction interface. We found that the introduction of the ammonium hydroxide during the Zn1?xCdxS deposition process can lead to a signi?cant reduction of Zn related hydroxide and oxide impurities. The modi?ed chemistry environment at the heterojunction interface facilitates the decrease of interface defects and promotes the interface microstructure quality. The improved heterojunction interface with suppressed interface recombination contributes to the enhanced open circuit voltage, ?ll factor and overall device performance.
关键词： Cu2ZnSnS4,solar cells,Zn1?xCdxS,ammonium hydroxide,heterojunction interface
更新于2025-09-16 10:30:52