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.