Role of donor/acceptor of doping on nonlinear optical properties of CdS nanocomposite decorated by carbon quantum dots and reduced graphene oxide

Abstract

Cadmium sulfide (CdS), reduced graphene oxide (RGO), carbon quantum dots (CQDs), CQDs/CdS and RGO/CdS nanocomposites have been synthesized. The products have been characterized by FESEM, XRD, UV–visible spectroscopy and diffuse reflectance spectroscopy (DRS). The nonlinear optical (NLO) properties of all products are measured using Z-scan technique at 532 nm wavelength. The results reveal that the formation of structures resulting in dπ–pπ delocalized systems makes the samples a perfect choice for NLO devices. NLO properties of CQDs/CdS is attributed to the charges or energy transfer between CQDs and CdS, in the CQDs/CdS hybrid. Overall, the laser excitation of the small CdS (36 nm) in the RGO/CdS hybrid material promotes electron and/or energy transfer to the RGO component. Therefore, RGO has more effect on NLO properties of CdS than CQDs on CdS nanocomposites. This enhanced electron transfer process leads to improved NLO performances, making the hybrid material a promising candidate for various optoelectronic applications.