Solution-processable graphene oxide as an insulator layer for metal-insulator-semiconductor silicon solar cells

Development of a high quality but low cost insulating layer is important for its application in photovoltaic cells. In this work, solution processable graphene oxide (GO) thin films were first utilized as an insulating layer to construct MIS silicon solar cells. The efficient water-soluble GO nano-sheets with controlled thickness produced a good contact with the hydrophilic silicon surfaces. The average open circuit voltage (V_OC) of the GO incorporated MIS silicon solar cell was increased by 0.2 V, while their power conversion efficiency (PCE) was demonstrated as 88% higher than that of the corresponding Schottky solar cells. The improvement of the device performance in the GO-based MIS silicon solar cell is attributed to the increased built-in potential as well as the reduced interface defect, resulting in reduced carrier recombination. The ability to establish a low-cost and solution-processable insulating layer will open the door for wide application in photovoltaic and other optoelectronic devices.