Research On The Synthesis Strategy And Mechanism Of Improving The Photoelectric Response Characteristics Of Nano-bismuth Oxybromide

With the rapid development of science and technology,optoelectronic devices play a significant role in the military industry and daily life.The development of visible light response optoelectronic materials is the key of the optoelectronic devices.BiOBr is a potential optoelectronic material due to its structure controllability,visible light response,and strong photoelectric properties.Therefore,it is a great significance to develop a feasible BiOBr material synthesis strategy and further reveals its photoelectric response mechanism.Based on the key issues of the low utilization of visible light excited photoelectrons and the poor O₂ adsorption,a co-modifying strategy of wide bandgap oxides and noble metal coupling has been proposed to improve the surface photovoltage response?SPV?of BiOBr.The mechanism of the improved nano-surface photovoltage response of BiOBr has been also revealed.In addition,a new tableting method was applied to replace the traditional powder based surface photovoltaic measuring systems to further improve the surface photovoltage response.The research content of this paper is as follows:First,two-dimensional BiOBr nanosheets with high photovoltaic response have been controllably prepared by hydrothermal method.The photovoltaic response mechanism based on surface adsorption of O₂ to capture electrons was revealed.On this basis,The SPV response of BiOBr nanosheets were improved by SnO₂-Ag co-modification.Based on the characteristics of atmosphere control/transient photovoltage spectrum and photoelectrochemical test,the mechanism of BiOBr photoelectric response improvement was studied.The improved photoelectric properties could be attributed to the SnO₂ modification to prolong the photo-carrier lifetime to improve the visible light photoelectron utilization,and the improved surface O₂adsorption and catalytic ability by Ag modification.Secondly,we developed a new tableting method to replace the traditional powder based surface photovoltaic measuring systems to further improve the surface photovoltage response.Consequently,Au/SrO/BiOBr nanocomposites were prepared and the SPV response was measured under the standardized tableting method.The Au/SrO/BiOBr nanocomposites displayed enhanced SPV response which could be attributed to the coupled SrO as an alkaline earth metal oxide wide-bandgap high-energy electron platform to prolong the lifetime of photogenerated electrons to improve the utilization of photoelectrons,and the modified Au as promoter to improve the surface O₂ adsorption and catalysis.As for this,the SrO and Au co-modification enhance the SPV response of BiOBr nanosheets.