Optical and electrical effects of thin reduced graphene oxide layers on textured wafer-based c-Si solar cells for enhanced performance

Abstract

Photoluminescence active amine-functionalized reduced graphene oxide (af-RGO) has been synthesized at room temperature with prolonged sonication to obtain a free floating, hexagonally arranged carbon network having larger dimensions ∼(20 μm × 15 μm) in aqueous medium. The presence of amine in an RGO network has been confirmed by Raman, FTIR and photoluminescence (PL) studies. It has been used as the top layer on c-Si solar cells. Its effect on solar cell parameters was investigated. The effect of dilution (10% to 90%) of aqueous af-RGO and its coverage on c-Si solar cells leading to optimum cell parameters has been studied. The respective reflected and transmitted photon fraction through the af-RGO thin film obtained from a spectral response graph was estimated. The suitability of the synthesized material for c-Si cells has been established through different characterization supports, like height profile and the surface coverage on a polished silicon surface, analysed by atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). It was observed that the 50% diluted sample shows the best performance with respect to the baseline parameters of solar cells. An enhancement of 4.6% in short-circuit current density (J_SC) and 4.8% in fill factor (FF) was achieved over the baseline parameters of the cell, while dip coating the baseline cell in the optimized dilution of af-RGO.