One-pot solvothermal synthesis of rGO-CAS nanobrick composites with enhanced photoelectric properties

A facile and efficient one-pot solvothermal synthesis of reduced graphene oxide-CuSbS₂ (rGO-CAS) nanobrick composite has been processed using ethylenediamine as reaction medium. In this case reduction of GO and the formation of CAS nanobricks on the surface of GO occurs simultaneously. The structural and morphological confirmation of the GO reduction and composite formation have been characterized using X-ray diffractometry, Raman spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy and X-ray photoelectron spectroscopy (XPS) analysis. Highly crystalline CAS material with orthorhombic structure in the composite has been observed through structural analysis. SEM micrographs reveal the brick-like structure of the CAS nanocrystals, which are well attached onto the individual layers of the graphene sheets. Improved optical absorption of the composite has been studied by absorption spectroscopy and the band gap tailoring of CAS nanobricks has also been achieved with GO matrix. XPS analysis verify the valence state of the composite material to be Cu⁺Sb³⁺(S²⁻)₂. The composite also exhibits a remarkable photoelectric response due to increased surface to volume ratio. The good electron trapping, shuttling ability of GO resulted in an efficient separation of the photo-excited charge carriers from rGO-CAS nanobrick composites. The photocurrent demonstrated by the composite is 46% higher than that of the bare CAS nanobricks.