Improved efficiency of graphene/Si Heterojunction solar cells by optimizing hydrocarbon feed rate

Abstract

Four different graphene films were synthesized via chemical vapor deposition by using acetonitrile with feed rates of 0.01, 0.02, 0.04, and 0.06 mL/min. Heterojunction solar cells were assembled by transferring as-synthesized graphene films onto n-Si. Solar cells based on graphene samples produced at 0.01, 0.02, 0.04, and 0.06 mL/min demonstrate power conversion efficiencies of 2.26%, 2.10%, 1.02%, and 0.94%, respectively. When HNO3 was used to dope the graphene films, the corresponding photovoltaic efficiencies were increased to 4.98%, 4.19%, 2.04%, and 1.74%, respectively. Mechanism for the improved efficiency of graphene/Si heterojunction solar cells was also investigated. © 2014 Zexia Zhang et al.