One-step in situ synthesis of antimony sulfide/reduced graphene oxide composite as an absorber layer with enhanced photocurrent performances for solar cells

Antimony sulfide/reduced graphene oxide (Sb₂S₃-rGO) composite was successfully deposited on titanium dioxide (TiO₂) nanorod array via a novel one-step chemical bath deposition method. The heterostructures were characterized by structural, optical, and electrochemical measurements. The self-assembled combination of Sb₂S₃ and reduced graphene oxide (rGO) nanostructure in the nanoarchitecture indicated a promising synergistic effect for solar cells with a remarkable enhanced electrochemical performance. The average crystallite size of 27 and 30 nm was calculated for Sb₂S₃-rGO and Sb₂S₃, respectively, from XRD measurement, and the diameter of nanoparticles grown on rGO nanosheet was estimated about 50 nm from FESEM images. Moreover, the result of electrochemical impedance spectroscopy (EIS) indicated that the TiO₂/Sb₂S₃-rGO bilayer interfacial resistance was approximately five times lower than that of TiO₂/Sb₂S₃. Additionally, TiO₂/Sb₂S₃-rGO exhibited a rapid and stable photocurrent density that was seven times greater compared to that of TiO₂/Sb₂S₃. These enhancements were mainly ascribed to the presence of the conductive rGO sheets that acting as an electron reservoir through retarding electron-hole recombination. These achievements strongly suggested the Sb₂S₃-rGO composite as a promising material for use as an absorber layer in solid state Sb₂S₃-sensitized solar cells.