Graphene oxide as an effective interfacial layer for enhanced graphene/silicon solar cell performance

We show that interface tailoring is an effective approach towards high performance G/Si Schottky-barrier solar cells. Inserting a thin graphene oxide (GO) interfacial layer can improve the efficiency of graphene/silicon solar cells by >100%. The role of the GO interfacial layer is systematically investigated by varying the annealing temperature and thickness of the GO film. It is found that GO cannot be treated as the common thought, i.e., an insulator. In other words, the G/GO/Si solar cell is not suitable to be treated as a "MIS" cell. In contrast, it should be regarded as a p-doped thin layer. The effects of GO film thickness on device response are also studied and there exists an optimal thickness for device performance. A record 12.3% (device size: 3 x 3 mm(2)) power conversion efficiency is achieved by further performance optimization (chemical doping graphene and antireflection coating).