Design strategies for energy-harvesting photovoltaics in diverse environments

Indoor photovoltaics (IPVs) are small and not optimized for versatile environments, making them environmentally sensitive. To expand the application of energy-harvesting photovoltaics, overcoming the current problems and mismatch loss is important. In this study, we found that IPVs are sensitive to changes in current density under low illuminance, and we introduced a protocol to reveal the modules resulting in the smallest standard deviation using current maps. For an IPV of 100 cm², dividing the area into nine cells was most beneficial irrespective of the illuminance considering loss due to contact. Therefore, we introduced the small-area, high-voltage concept to IPVs and revealed the module design that minimizes the mismatch loss. As a result, we demonstrate a rough taxonomic classification into three groups that can be used as fundamental information for selecting an IPV. We expect that scaling from two dimensions to three dimensions is worthy of further research.