Process-to-panel modeling of a-Si/c-Si heterojunction solar cells

Abstract

The cell-to-panel efficiency gap observed in a-Si/c-Si heterojunction solar cells is one of the key challenges of this technology. To systematically address this issue, we describe an end-to-end modeling framework to explore the implications of process and device variation at the module level. First, a process model is developed to connect the a-Si deposition parameters to the device parameters. Next, a physics based device model is presented which captures the essential features of photo-current and diode injection current using the thermionic-diffusion theory. Using the process and device models, the effects of process conditions on cell performance are explored. Finally, the performance of the panel as a function of device and process parameters is explored to establish panel limits. The insights developed through this process-to-panel modeling framework will improve the understanding of the cell-to-panel efficiency gap of this commercially promising cell technology.