Semitransparent Organic Photovoltaic Achieving 12.98% Efficiency and 33.95% Average Visible Light Transmittance by Employing PPT‐3 With Large Bandgap and Narrow Photon Harvesting Range

A broad bandgap polymer PPT‐3 with optical bandgap of 2.25 eV and narrow photon harvesting range of 90 nm was deliberately selected to match with one narrow bandgap acceptor BTP‐eC9 for preparing semitransparent organic photovoltaics (ST‐OPVs). The optimal weight ratio of PPT‐3 to BTP‐eC9 is about 0.7:1 for well balancing the power conversion efficiency (PCE) of 13.72% and the average visible light transmittance of active layer (AVTF) of 61.64%. The PCE of organic photovoltaics (OPVs) can be further increased from 13.72% to 14.73% by incorporating 0.05 wt.% TFB with high hole mobility properties, as confirmed from the grazing‐incidence wide‐angle X‐ray scattering characterization. The Au (1 nm)/Ag (10 nm) was fabricated as the top electrode to prepare ST‐OPVs exhibiting a PCE of 12.98%, an average visible light transmittance (AVT) of 33.95% and a light utilization efficiency (LUE) of 4.41%. This work indicates that the selection of a broad bandgap donor with narrow photon harvesting range and reduced donor content should be the smart strategy for achieving ST‐OPVs.