Pathways to High Efficiency Perovskite Monolithic Solar Modules

With the rapidly improving efficiency and stability of perovskite solar cells, the transition of small area device fabrication innovations into modules is becoming increasingly important for the commercialization of this technology. The record efficiencies of small perovskite cells are already approaching that of the best silicon crystal solar cells, but the module efficiencies are still far behind. Understanding the factors that cause the cell-to-module (CTM) efficiency loss is critical for large area perovskite module development. Here, we experimentally validate a comprehensive model that analyzes the CTM efficiency loss with a precision better than 97%. Using the model, we decipher the impact of the critical module components and fabrication variables, including perovskite band gap, transparent electrodes, scribing lines, and film uniformity, on module aperture efficiency. Our analysis provides pathways toward the aperture efficiency ceiling of 25.8% for single-junction perovskite solar modules with a band gap of 1.49 eV. Enlightened by the model, we find that tandem structures have intrinsic merit to achieve high efficiency perovskite modules of 28.4% with a much lower CTM derate due to the smaller photocurrent but larger photovoltage.