A novel approach to utilize thiol reduced graphene oxide as linker molecule for Cu2ZnSnS4 sensitized solar cell

A new strategy was proposed to improve the efficiency of Cu2ZnSnS4 (CZTS) sensitized solar cell by utilizing thiol reduced graphene oxide (TrGO) to replace conventional linker molecule, mercaptopropionic acid (MPA). TiO2-TrGO-CZTS composite structure formed via the remaining carboxyl and exposing thiol groups in TrGO, which guaranteed stable links between TiO2 and CZTS. Based on the fabrication of TiO2-TrGO-CZTS composite electrode, CZTS sensitized solar device was assembled. Besides, TiO2-hydrazine hydrate reduced graphene oxide (HrGO)-CZTS and TiO2-MPA-CZTS electrodes as well as the devices were also constructed. Upon measuring the photoelectrochemical and photoelectric performance, it was found that the highest power conversion efficiency of 0.133% was obtained in the case of TiO2-TrGO-CZTS, which was enhanced by 27% and 28% compared to HrGO and MPA decorated devices, respectively. The improvement of photoelectric performance was mainly attributed to more excited electrons and less recombined charge. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.