Wide-gap non-fullerene acceptor enabling high-performance organic photovoltaic cells for indoor applications

Organic photovoltaic cells are potential candidates to drive low power consumption off-grid electronics for indoor applications. However, their power conversion efficiency is still limited by relatively large losses in the open-circuit voltage and a non-optimal absorption spectrum for indoor illumination. Here, we carefully designed a non-fullerene acceptor named IO-4CI and blend it with a polymer donor named PBDB-TF to obtain a photoactive layer whose absorption spectrum matches that of indoor light sources. The photovoltaic characterizations reveal a low energy loss below 0.60 eV. As a result, the organic photovoltaic cell (1 cm(2)) shows a power conversion efficiency of 26.1% with an open-circuit voltage of 1.10 V under a light-emitting diode illumination of 1,000 lux (2,700 K). We also fabricated a large-area cell (4 cm(2)) through the blade-coating method. Our cell shows an excellent stability, maintaining its initial photovoltaic performance under continuous illumination of the indoor light source for 1,000 hours.