| With the development of society,the traditional fossil energy depletion and environmental pollution problems have become increasingly prominent,looking for renewable and clean new energy sources is imminent.As an inexhaustible source of renewable energy,solar energy has the advantages of safety,environmental protection,and no pollution,providing new ideas for solving the energy crisis.However,the high cost,complicated manufacturing process or the presence of toxic elements limit their application in daily life.Therefore,screening and designing new types of solar photoelectric materials and improving photoelectric conversion efficiency have become new research hotspots in the energy field.With the continuous improvement of computational capabilities and physical models,it has become possible to perform large-scale screening and design of new semiconductor optoelectronic materials from a global perspective.This work is based on the first-principles ab initio method.Through computer simulations of Bi/Sb-based sulfur halides,oxyhalides,and two-dimensional TMDCs superlattice structures,we have screened out three types of Bi/Sb based compounds as candidate photovoltaic materials.In addition,combined with the idea of high-throughput calculations,we have explored the physical causes behind the bandgap and optical properties of the eleven types of two-dimensional superlattice structures.The purpose of theoretical screening and optimization design is achieved.Our findings are as follows:1.Three types of Bi/Sb based compounds were selected as candidate optoelectronic materials.Under the premise of ensuring diversity of chemical composition and crystal structure,we systematically studied the physical properties of 36 Bi/Sb-based sulfur halides and oxyhalides through density functional theory,such as thermodynamic stability,electronic structure,and electron/hole effective quality.Based on the results,we found a series of candidates suitable for optoelectronic applications,including two types of compounds(BiSeCl/Br/I and Bi3Se4Br)as potential solar absorber materials,three types of compounds(Bi3Se4Br,BiSeCl/Br/I,and BiOI)as potential radiation detection materials,and three types of compounds(BiOCl/Br,SbOF,and Sb4O5Cl2/Br2)as potential p-type transparent conducting materials.2.Explore the regulation of the photoelectric properties of transition metal dichalcogenides(TMDCs)by superlattice structures.Based on high-throughput calculation methods,we systematically studied the energy bands and absorption spectra of two-dimensional TMDCs superlattice structures.According to the different proportions and stacking methods,the heterostructure has a transition from indirect band gap to direct band gap,from semiconductor to metal,and the band gap value is continuously adjustable.We have found that for different combinations,the in-plane stress caused by lattice mismatch is the main factor that causes the above transition.This study will facilitate the controlled preparation of two-dimensional semiconductor materials with direct gaps and metallic properties,broadening the application of two-dimensional materials in the field of optoelectronics. |
