Enhancing photovoltaic performance of PbS/rGO nanocomposites: The role of buffer layer of ZnS/rGO nanocomposites

In the present study, we attempt to report an improvement in the photovoltaic performance of PbS/graphene nanocomposites, which were employed as the photovoltaic materials, using the layers of ZnS nanoparticles (NPs) and ZnS/graphene nanocomposites as n-type buffer layers. Graphene oxide (GO) sheets were used as graphene source and the ZnS/GO and PbS/GO nanocomposites were synthesized by a simple and cost-effective co-precipitation method using l-cysteine amino acid and Dodecylbenzenesulfonic acid (DBSA) as the surfactants, respectively. Characterization results such as X-ray diffractometer (XRD) patterns and X-ray photoelectron spectroscopy (XPS) results indicated that, the GO sheets were changed into reduced graphene oxide (rGO) during synthesis process. The photovoltaic measurements indicated that rGO in ZnS/rGO buffer layer had a more significant role in enhancing the photovoltaic performance of the photovoltaic device compared to ZnS (NPs) buffer layer. Moreover, these measurements demonstrated that the ZnS/rGO caused an increase in the short-circuit current (JSC) of the photovoltaic device, which led to improving the photovoltaic performance of the device.