High Efficiency Semi-Transparent Organic Photovoltaics

Considering the vast surface areas of windows and facades in modern urban environments, developing building-integrated photovoltaics employing transparent photovoltaic cells provides an opportunity to convert solar energy to electricity rather than generating waste heat. In this work, a non-fullerene acceptor based near-infrared (NIR) absorbing ternary component cell combined with a thin, semitransparent, high conductivity Cu-Ag alloy electrode was used to demonstrate semitransparent organic photovoltaic cells (ST-OPVs). A combination of optical outcoupling and anti-reflection coatings leads to enhance visible transmission, while reflecting the NIR back into the cell where it is absorbed. The optimized devices have the light utilization efficiency (LUE), which is equal to the product of the power conversion efficiency (PCE) and the average photopic transparency compared with a conventional semitransparent cell, twice that of a cell lacking these coatings. A maximum LUE = 3.56± 0.11% is achieved for a ST-OPV with a PCE = 8.0± 0.2%% at 1 sun, AM1.5G simulated emission.