Schottky Solar Cells Based On Surface Passivated MoS₂

With the continuous development of solar cells,the third generation solar cells,which use new materials such as intermediate band materials,low-dimensional nanomaterials and perovskite,have become one of the hotspots of solar cell research in recent years.The molybdenum disulfide?MoS₂?is widely used in solar cell preparation because the process of Schottky solar cells with MoS₂ is simple and extremely economical.There exist many sulfur vacancies on the surface of intrinsic MoS₂,and those defects capture photogenerated carriers,which makes them cannot be collected by electrodes,affecting the conversion efficiency of solar cells.This study aims to improve the conversion efficiency of solar cells through Ar/O₂ plasma treatment,which was applied to MoS₂/Si solar cells to effectively passivate the defects on the surface of molybdenum disulfide without destroying the film.Specific research contents are as follows:1.Preparation of MoS₂ films.Firstly,to prepare a large uniform molybdenum disulfide film,molybdenum foil was annealed at high temperature to recrystallize and to increase the grain boundary.Subsequently,sulfide annealing of molybdenum foil was conducted by chemical vapor deposition,and multilayer molybdenum disulfide films were prepared by adjusting the reaction time.2.Surface passivation of MoS₂ films.In order to weaken the oxidation and etching effect during the passivation of MoS₂ films with pure oxygen plasma,Ar/O₂ plasma treatment was used in this study.The density of oxygen plasma was reduced and the electron temperature of the plasma was lowered by adding Ar gas.In this paper,the passivation effect was studied with different ratios of Ar/O₂,and the surface morphology,layer number,element and lattice structure of passivated MoS2 films were analyzed.We proved that the surface of MoS₂ films can be effectively passivated without damaging the lattice structure and affecting the film thickness with optimized Ar/O₂ ratio,and this paved the way for the subsequent study.3.Study of MoS₂/Si solar cells based on surface passivation.MoS₂/Si solar cells with different Ar/O₂ ratios were fabricated in this study.The highest device performance was achieved with solar cells treated using the Ar/O₂ ratio of 5:5,and the measured conversion efficiency was 5.1%.The open circuit voltage and short circuit current of the solar cell device were 0.4 V and 6.0 mA/cm²,respectively.The filling factor was 53%.The effects of different Ar/O₂ ratios on the corresponding MoS₂/Si solar cell devices were also analyzed in the presented work.Our study provides some experimental information to help improve the understanding of the mechanism of surface passivation and its practical application.