Combining Thickness Reduction and Light Trapping for Potential Efficiency Improvements in Perovskite Solar Cells

摘要

In this contribution it is shown that the efficiency of perovskite solar cellsrnbased on CH_3NH_3PbI_3 can be increased further by combining thicknessrnreduction of the perovskite layer and light trapping. A physical model for therncurrent/voltage curve of pin solar cells is used to reveal the beneficial impactrnof thinning on cell efficiency. If interface recombination is kept at moderaternlevels, the model shows that there is a potential efficiency increase abovern20% relative (+3% absolute) when thickness is reduced from 500 to 200 nm,rnprovided total light absorption is maintained. A rigorous optical model isrnemployed to calculate light absorption on typical state–of–the–art layer stacksrnpatterned with sinusoidal grooves on ITO coated glass. The results suggestrnthat solar light absorption in a flat, 500nm thick film, can be matched by arn200nm thick perovskite layer on a sinusoidal texture, while using 300nmrnleads to several sinusoidal parameter combinations delivering the same lightrnabsorption. Since the structuring step must be compatible with low costrnprocessing, it is shown that direct laser interference patterning (DLIP) isrncapable of delivering +3% absolute efficiency increase, while offering arntypical photovoltaic module cost reduction of 10%.