Periscope‐Inspired High‐Performance Semitransparent Organic Photovoltaics With Dual Surface‐Reflection Optical Structure

Featuring unique selective absorption, the semi‐transparent organic photovoltaics (ST‐OPVs) hold a bright future for building integration. However, the prevailing ST‐OPVs take a transmission mode (t‐ST‐OPV) and can hardly achieve a good compromise between the averaged visible transmission (AVT) and power conversion efficiency (PCE), rendering a poor light utilization efficiency (LUE) and limiting their practical application. Inspired by the optical path of a periscope, this work developed an ST‐OPV structure with a reflection optical path (r‐ST‐OPV), which takes dual or multiple reflections to make a transmission effect. This structure mitigates the reflection loss and significantly enhances the absorbing selectivity. Facilitated by the sophisticated optical manipulation technique, the r‐ST‐OPV with almost full invisible transmission (AVT ∼ 92.2%) and a PCE of 8.27% is achieved, corresponding to a record LUE of 7.62% among all ST‐OPVs. This work opens up the avenue toward high‐performance organic solar windows for practical application.