Integrated effect of hierarchical structure combining isotropic worm-like pit with anisotropic inverted nanopyramid for quasi-omnidirectional c-Si solar cell

Abstract The significance of efficient antireflection over a wide light incident angle (θ) range without sacrificing surface passivation too much increases with the rapid development of photovoltaic industry. Here, worm-like pit (WLP)/inverted nanopyramid (INP) hierarchical structure was realized on c-Si by constructing INP on modified WLP with large lateral size. The INP was obtained through Ag assisted chemical etching based nanopore reshaping in nanostructure rebuilding (NSR) solution. The anti-reflectance performance especially the omnidirectional ability accompanied with the surface passivation effect of both micro pyramid (MP) and WLP/INP was systematically investigated and compared. Additionally, the hierarchical structure based c-Si cell with an efficiency up to 18.5% was achieved, which is 0.12% absolutely higher than that of MP based counterpart (18.38%). Most significantly, the WLP/INP based cell can always possess a higher electric output power over the θ range from −80° to 80° with a highest relative power enhancement of 3.0% compared with that of the MP based one. The above surface processing is facile and scalable, providing an alternative way for the obtaining of c-Si solar cells with large electrical energy output during practical application.