Homojunction Doping for Efficient Hole Extraction in Polymer Solar Cells

Abstract

Hole transporting layers (HTL) in polymer solar cells remain a subject of importance to enable enhanced efficiency and stability compared to the benchmark PEDOT:PSS. The design of an interlayer based on the same polymer as the one used in the bulk heterojunction (BHJ) is reported here. In this HTL, the polymer is doped, thus forming a so‐called homojunction. The conductivity of PTQ10 doped with magic blue is optimized for varying dopant concentrations. The resulting solar cells show competing power conversion efficiency as the widely used PEDOT:PSS and improved stability. This strategy opens the route toward the development of deep‐lying work function HTL and is promising for future BHJ materials with deep‐lying highest occupied molecular orbital polymers.