Surface doping of non-fullerene photoactive layer by soluble polyoxometalate for printable organic solar cells.

The non-fullerene photoactive layer (PTB7-Th:IEICO-4F) film is first immersed into a PMA solution to induce an effective surface p-type doping. An improved hole-collection and a high PCE of 11.37% was obtained, although the non-fullerene OSCs were without a commonly evaporated MoO3. This surface doping technique is an effective and feasible strategy for the printable electronics technology.