Tailoring the Gr/Si heterointerface by decorating CdSe/ZnS QDs for Photovoltaics

Abstract

Photovoltaic devices are an emerging technology in this study, we fabricated a large area and reliable Graphene/Silicon solar cell by introducing Quantum Dots for 540nm and 650nm wavelength emission. Silicon Dioxide was grown by thermal oxidation. Gr/Si heterojunction was made by use of lithography. Graphene was grown by CVD and then transferred to Si to make the heterojunction. Quantum dots were coated by drop-casting and characterization was done for electrical properties. Monolayer graphene was confirmed by Raman spectroscopy. And ID band shows that the graphene was very less defective. Emission spectra of QD’s were confirmed by Photoluminescence with bands at 527nm and 650 nm. Electrical properties were studied by Current-voltage and capacitance-voltage characterization. A clear enhance in current density and efficiency has been noted. Around 134% increase in current density is being observed with about 265% increase in Efficiency. Results show that Quantum Dots of CdSe/ZnS has good optical properties when it interacts with Graphene/Silicon solar cell structure and helps improve Photo Conversion Efficiency. This shows a promising future of quantum dots as the top layer of solar cells.