Enhancing the efficiency and stability of Organic/Silicon solar cells using graphene electrode and Double-layer Anti-reflection coating

Abstract

Silicon (Si) based organic/inorganic hybrid solar cells have attracted much attentions due to their low-temperature solution process and high power conversion efficiency (PCE). However, the use of metallic grids electrode impedes the efficient light absorption, and the hybrid solar cells still suffer from poor air stability. Here, we demonstrate the fabrication of high-efficiency, air stable organic/Si heterojunction solar cells by using a graphene transparent electrode as well as a double-layer anti-reflection coating (DL-ARC). The use of highly transparent graphene film could avoid the strong light blocking effect of conventional metallic grids electrode and ensure the effective carrier collection. Meantime, the light-harvesting of Si wafer is remarkably enhanced by the DL-ARC based on polymethyl methacrylate (PMMA) and Poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) stacking layer. The assembled organic/Si heterojunction devices present outstanding photovoltaic performance with a PCE as high as 13.01% under AM 1.5G irradiation. More importantly, thanks to the protective effect of graphene/PMMA layer, the devices exhibited an excellent stability, and 94% of the pristine efficiency could be maintained after storing in air for 4 months without any encapsulation. Our work paves the way towards the fabrication of hybrid solar cells with high performance and stability.