High-efficiency, air stable graphene/Si micro-hole array Schottky junction solar cells

Abstract

Graphene/Si hole array (SiHA) Schottky junctions show great promise as high-efficiency, cost-effective solar cells. However, their applications are still limited by the severe surface recombination of the nano-hole SiHA and inferior device stability arising from volatile oxidant doping. Here, we demonstrate the construction of high-efficiency graphene/SiHA devices with enhanced device performance and stability. The micro-hole SiHA fabricated by photolithography and reaction ion etching (RIE) possesses a smooth surface, thus ensuring a low surface recombination velocity. Also, the light harvesting of the micro-hole SiHA could be readily tuned by adjusting the hole depth. Introduction of the micro-hole SiHA, along with the use of AuCl₃ for graphene doping, gives rise to a high power conversion efficiency (PCE) of 10.40% for the graphene/SiHA devices. Additionally, the device stability is substantially improved and shows a relatively low degradation ratio after storing in air for 3 months. It is expected that the graphene/SiHA devices will have important applications in new-generation Si solar cells.