Joule heat generation from reverse and forward currents in thin film solar cells

The heat generation in thin film solar cells during the operation of the cell or under stressing conditions has been rarely investigated in literature. However, heat generation can accelerate the deterioration of device parameters and foster the materials and interface decomposition. Joule heat is an inevitable source of heat generation in solar cells which initiates due to the flow of current in the solar cells. This phenomenon has been systematically investigated for a CZTSSe Kesterite thin film solar cell through an advanced model created by coupling the optical-electrical-thermal modules in a simulation platform. Moreover, defect generation in the absorbing layer of solar cells (under the stress of elevated temperature) has been modeled and inserted in the simulation model as well to track the changes in the Joule heat generation rate. The Joule heat generation across the cell has been mapped for both forward current and reverse currents and the impact of elevated temperature (from 300 to 1000 h aging time) has been simulated and compared with the Joule heat generated under normal operating conditions. The role of defects in the Joule heat generation rate has been discussed and the heat distribution across the 3D structure of the cell has been mapped out using the coupled simulation model.