Heat-Insulating Multifunctional Semitransparent Polymer Solar Cells

Semitransparent organic photovoltaics (ST-OPVs) have attracted extensive attention due to their potential for integration into the windows of buildings. Herein, we propose a dual-functional ST-OPV device that is not only highly efficient but also very effective for heat insulation. By introducing non-fullerene acceptor with enhanced near-infrared absorption and distributed Bragg reflectors for selectively enhancing the transmittance in visible wavelengths while keeping high reflectance for near-infrared light, the ST-OPVs generate over 6% power conversion efficiency with high visible light transmission of over 25% and outstanding infrared radiation rejection rate of over 80%. Our results show that with proper design of ST-OPVs, they can be used not only for generating power from sunlight but also for solar shading and heat insulation, which opens up a new application of OPVs for both energy harvesting and saving. Commercial heat-control window films applied to the interior or exterior of glass windows to reduce the amount of UV, visible, and infrared light from sunlight are already widely used to improve energy efficiency of buildings, while semitransparent organic photovoltaics (ST-OPVs) have not yet been commercialized for power-generating window applications. Here we have demonstrated for the first time that power-generation and heat-insulation functions can indeed be integrated together in specially designed ST-OPVs, which not only provide good power-generation properties but also show heat rejection comparable with that of commercial window films. A value-added ST-OPV with high PCE and AVT in addition to an excellent infrared radiation rejection rate have been demonstrated, which paves the way for the new application of OPV technology for both power generation and power saving. A dual-functional semitransparent organic photovoltaic cell that integrates both power-generation and heat-insulation functions is demonstrated. By introducing non-fullerene acceptor with enhanced near-infrared absorption and distributed Bragg reflectors for selectively keeping high reflectance for near-infrared light, the solar cell generates over 6% power conversion efficiency with high visible light transmission of over 25% in addition to an excellent infrared radiation rejection rate of over 80%.