Development of two-terminal perovskite/Si tandem solar modules and their application to building-integrated and vehicle-integrated photovoltaics

Abstract We report our recent progress in the development of practical technologies for two-terminal perovskite/Si tandem solar modules, using fabrication methods developed for perovskite single-junction modules. These methods enabled us to confirm an independently measured efficiency of 19.4% for a 700 cm 2 perovskite single-junction module. We also present tandem solar cell technology represented by a typical baseline perovskite/Si tandem solar cell that achieved an independently measured efficiency of 32.6% (active area: 1.02 cm 2 ). Using upsized perovskite/Si tandem solar cells, we obtained a module power output of 59.2 W (in-house measurement). We discuss color‑tone stability under process variation, evaluate the impact of color-tone variations on current matching between the top and bottom cells, and demonstrate prototypes of a building-integrated photovoltaic (BIPV) module and a three-dimensional curved vehicle-integrated photovoltaic (VIPV) module to gain insights into the optical design required to tune module appearance for BIPV/VIPV deployment. These results outline a development pathway coupling efficiency gains, long-term durability, and aesthetic control for perovskite/Si tandem solar modules.