Investigation On Electronic Structure And Solar Energy Conversion Performance Of (B₂₀/Ag₃PO₄，GaX/SnS₂，X=S,Se)Semiconductor Heterostructures

Semiconductor heterostructures have shown great potential in the fields of photocatalytic hydrogen generation and photovoltaic applications,and are considered to be one of the most promising new energy materials.However,at present,due to the massive possibilities and complex assembly technology of semiconductor heterostructures,it is very difficult to screen the heterostructures with excellent performance.The photocatalytic and photovoltaic performance of semiconductor heterostructures depend on its electronic structure and optical properties.The first principle calculation based on density functional theory（DFT）can effectively predict the above two properties,and it is a powerful tool to study the photocatalytic and photovoltaic properties of semiconductor heterostructures.In this paper,two heterostructures of B₂0/Ag₃PO₄,GaX/SnS2（X=S,Se）are selected as the research object,and their electronic structures and optical properties are studied by first-principles calculation.The specific contents are as follows:（1）The electronic structure,optical properties and interface charge transfer properties of boron nanoclusters B₂0,Ag₃PO₄ and B₂0/Ag₃PO₄ heterostructures were studied.Compared with B₂0 and Ag₃PO₄,the band gap of B₂0/Ag₃PO₄ heterostructures is greatly reduced.The decrease of band gap makes the absorption spectrum of heterostructures red-shifted,and greatly increase the absorption intensity of heterostructures in the visible light range,thereby improving the utilization of solar energy.B₂0/Ag₃PO₄ heterostructures form a type-Ⅱ band arrangement at the interface,which can effectively reduce the recombination of photo-generated electrons and holes,therefore improving the quantum yield.In addition,in order to quantify the interface potential energy of the heterostructures,a fitting method based on Morse function is proposed.A comparative study of multiple boron nanomaterial heterostructures shows that this method is not limited to predicting the interface interaction strength of the B₂0/Ag₃PO₄ heterostructures.The above results reveal the nature of interface interaction for the first time,which are of great significance for the design of boron nanostructure devices with novel properties.（2）The electronic structure,optical properties,power conversion efficiency（PCE）and other properties of the two-dimensional layered materials GaX（X=S,Se）,SnS2 and two-dimensional GaX/SnS2 heterostructures were studied.Compared with the components before coupling,the band gap of the heterostructures is significantly reduced,which enhances its ability to absorb visible light.The Type-Ⅱ band arrangement at the interface will promote the transfer of carriers from one component to another,thereby improving the separation efficiency of electron-hole pairs in the heterostructures and accelerating the generation of photo-generated current.The heteroatom doping methods,especially N atom doping,can significantly improve the power conversion efficiency（PCE）of the two-dimensional GaX/SnS₂ heterostructures to 16%（a 162%increase from the original heterostructures）.The above results indicate that heteroatom doping is an effective solution for the development of highly efficient two-dimensional heterojunction photovoltaic devices.