基于薄膜退火的MoS_2/SiO_2/Si异质结太阳能电池光伏性能提高

Enhancement of photovoltaic performance of MoS_2/SiO_2/Si heterojunction solar cells by film annealing

为了制备高效的MoSi/SiO_2/Si异质结太阳能电池,利用磁控溅射技术制备MoS_2薄膜,并在硫气氛下对MoS_2薄膜进行退火处理。分别用退火和未退火的MoS_2薄膜制备MoS_2/SiO_2/Si异质结太阳能电池,研究了退火对MoS_2薄膜的微观结构和MoS_2/SiO_2/Si异质结太阳能电池光电性能的影响。实验结果显示,相比于未退火的,经过退火处理的MoS_2薄膜的拉曼峰半高宽(FWHM)变窄,峰强增强,显微荧光光谱中也出现明显的激子发光峰。由此表明,退火处理使MoS_2薄膜由非晶向晶态转变,薄膜的体缺陷减少,异质结太阳能电池的开路电压和填充因子得到提升,器件转换效率从0.94%提高到1.66%。不同光照强度下的J-V测量和暗态的J-V测量结果表明,经退火处理的MoS_2薄膜的异质结太阳能电池具有较高的收集电压和更接近于1的理想因子,这归因于退火导致MoS_2薄膜的体缺陷的减少,近而降低了MoS_2/SiO_2/Si异质结太阳能电池器件的体缺陷复合。

MoS2thin films were prepared using magnetron sputtering technology and annealed in sulfur surrounding.Then, MoS2/SiO2/Si heterojunction solar cells were fabricated with annealed and unannealed MoS2 thin films respectively.The effects of annealing on the microstructure of MoS2 thin films and the photovoltaic performance of MoS2/SiO2/Si heterojunction solar cells were investigated.Compared with the unannealed MoS2 thin film,the full width at half maximum（FWHM）of Raman peaks of the annealed MoS2 thin film becomes narrower,the peak intensities are stronger,and exciton peaks are emerged in microscopic PL spectrum.The results indicate that the MoS2 films transformed from amorphous to crystalline by annealing and bulk defects in films were reduced,which can increase the open-circuit voltage and the fill factor as well as the conversion efficiency（from 0.9 4% to 1.6 6%）of the devices.The variable intensity J-V measurements and the dark J-V measurements demonstrate that the annealed MoS2/SiO2/Si heterojunction solar cells have higher collection voltage and ideality factor n nearly close to 1,which due to the decrease of the bulk defects density of the MoS2 thin films as well as the decline of the defects recombination of the device leaded by annealing.