Bifacial crystalline silicon homojunction cells contacted with highly resistive TCO layers

Abstract

This study explores the needed properties of Transparent Conductive Oxides (TCOs) for bifacial homojunction solar cells with potentially passivated contacts. TCO layers with different electrical and optical properties have been tested on both sides of n-type homojunction cells. The high lateral conductivity provided by the diffused emitter and back surface field (BSF) greatly reduces the constraints on TCO electrical properties in such structures. An understanding of the required properties of TCO for advanced homojunction applications is given. Hence different O2-rich Indium Tin oxide (ITO) layers are analyzed optically and electrically before being implemented in homojunction solar cells to evaluate their influence on the device performances. All in all moderately conductive TCOs are shown to be suitable for such applications, allowing better optical properties without inducing resistive losses in the devices.