Understanding Silicon Heterojunction Solar Cells with nc-SiC/SiO2 as an Alternate Transparent Passivating Front Contact and Computational Design Optimization

Abstract

The potential performance of silicon heterojunction solar cells applying transparent passivating contact (TPC) at the front side, based on a nc-SiC:H/SiO2 layer stack, is modeled and investigated. Herein, a complete multiscale electro-optical device model of TPC solar cells is developed. The model is then used to understand and analyze such cells and search for potential conversion efficiency improvement paths. The influences of contact layer thicknesses and other properties on device performance are studied. An algorithm-based optimization of cell electro-optical performance is performed. It is implemented by coupling a genetic algorithm with a finite element method-based TPC solar cell device model. Optimum front contact layer thicknesses are calculated. For optically optimized TPC contact layer thicknesses, an optical improvement of around 0.5 mA cm−2 is found. Moreover, for complete electro-optical optimization of TPC layers, about 0.27% absolute value increment in power conversion efficiency is calculated. At the rear side, proper designing of optimizing carrier transport using active dopant concentration of p-type a-Si:H layer and indium tin oxide layer has shown a potential to reach power conversion efficiency beyond 25%.