Optimal design and photoelectric performance study of micro-lens light trapping structure for CIGS thin film solar cell in BIPV

Abstract In this paper, an optimal design method of micro-lens light trapping structure for thin film solar cells applied to building integrated photovoltaic (BIPV) is proposed. Under three common scenes of BIPV, including lighting roof, sunshade and building facade, the optimal design and photoelectric performance study of Copper Indium Gallium Selenium (CIGS) thin film solar cells with micro-lens light trapping structure are studied. Among the three kinds of micro-lens light trapping structures, V-shaped, semi-cylindrical and concave, the light capture performance of V-shaped micro-lens light trapping structure is the best. The V-shaped micro-lens light trapping structure with a vertex angle of 70° and a groove depth of 100 μm has the best light capture performance in lighting roof and sunshade scene, which can increase the annual radiation flux of the absorption layer incident surface by 4.45% and 2.84% respectively. The V-shaped micro-lens light trapping structure with a vertex angle of 60° and a groove depth of 200 μm has the best light capture performance in building facade scene, which can increase the annual radiation flux of the absorption layer incident surface by 7.63%. When the light source is vertically incident, these two V-shaped micro-lens light trapping structures can increase the short-circuit current density by 15.57% and 7.11% respectively.