Color-neutral, semitransparent organic photovoltaics for power window applications

We demonstrate a semitransparent organic photovoltaic cell that achieves a power conversion efficiency of 10.8% and visible transparency of ∼50% using a nonfullerene acceptor (NFA) featuring strong near-infrared (NIR) absorption and simple synthesis. Contrary to expectations, stronger NIR absorption and closer molecular packing are obtained by employing an additive in these partially, instead of fully fused, rigid NFAs. By combining NIR-absorbing material sets with an optical outcoupling structure as well as transparent electrode, we overcome the trade-offs between efficiency, transparency, and device appearance. These results surpass other semitransparent solar cell technologies based on organic and other thin-film materials systems, showing a promising future for ST-OPVs as power-generating windows and other solar energy harvesting applications.