Transparent Polymer Photovoltaics for Solar Energy Harvesting and Beyond

Polymer photovoltaics have become a promising alternative energy due to lightweight properties, environmental friendliness, and solution processability. Transparent organic photovoltaics in particular have been recently receiving more attention in the photovoltaics field due to their unique potential in future applications beyond mere harvesting of solar energy. This perspective is further enhanced by the recent developments of high-performance polymer photovoltaics (including infrared absorbing materials and devices) that could achieve superior visible transparency and power conversion efficiency. To realize high-performance transparent organic photovoltaics, the main strategy is to shift the active-layer absorption spectrum to the infrared region by designing new low-bandgap donors and non-fullerene acceptors, and to reduce the invalid absorption by developing new transparent electrode materials. The potential applications are diverse, especially for spectrum-sensitive ones such as the greenhouse in agriculture. Finally, some key research areas of transparent organic photovoltaics that may deserve further attention are discussed.