Analysis of AgNW-TCO hybrid window electrode for silicon heterojunction solar cells via angular matrix framework

Abstract

Silicon heterojunction (Si-HJT) solar cells are one of the most efficient silicon-based solar cells, due largely to their high open-circuit voltages. For the transparent conductive oxide (TCO) layers, there is a design trade-off between their conductance and their parasitic light absorption, and this trade-off can be a performance-limiting factor for Si-HJT solar cells. It has been demonstrated that silver nanowire (AgNW) networks with superior optical and electrical performances, can complement TCOs. To evaluate the performance of AgNW-TCO hybrid electrodes for Si-HJT cells, it is beneficial to numerically simulate and optimize the optical and electrical performances of the entire device. However, the dimensions of the AgNWs are massively different to the dimensions of the other components of the cells, making individual modeling methods incapable. In this paper, we use an angular matrix framework (AMF) to resolve the challenge, where matrices are used to describe the transition of the angular distribution of the light when it is reflected or transmitted at the interface, or absorbed in the bulk. These matrices pass optical information between nanoscale and microscale components of the cell structure. Using AMF, we calculated the optical properties of the devices, and demonstrated that the AgNW-TCO electrode has advantages over a TCO electrode. Guidance on how the optimization of the composite electrode can be achieved was provided.