13.7 % Efficient Graphene/Si Heterojunction Solar Cells with One‐Step Transferred Polymer Anti‐Reflection Layer for Enhanced Light Absorption and Device Durability

Abstract Graphene/Silicon (Gr/Si) heterojunction shows great potential as high‐efficiency, cost‐effective solar cells compared to traditional Si solar cells. However, the high optical loss of c‐Si, mainly originating from abrupt change of refractive index at air/Si interface, and the unsatisfactory conductivity of practically prepared graphene layer, still hinder their extensive applications. Herein, we report the performance improved Gr/Si solar cells by depositing a polymathic methacrylate (PMMA) anti‐reflection coating (ARC) layer through a one‐step transferred method. The graphene and PMMA ARC with specific thickness were transferred on n‐type Si wafer at the same time, which reduces production steps and obtains high‐quality graphene layer. By tuning the thickness of the PMMA layer, the reflection can be reduced obviously. Companying with the HNO 3 vapor doping for graphene, the Gr/Si heterojunction solar cell with a high power conversion efficiency (PCE) of 13.7 % was achieved. In addition, the durability of the device is improved under HNO 3 doping. Considering the easy and cost‐effective solution processed capability of the one‐step transferred graphene and PMMA ARC layer, we believed that PMMA/Gr/Si is a feasible low‐temperature technique for high‐efficiency Si solar cells.