Synergistic p-doping and interface passivation of P3HT by oxidized organic small molecules toward efficient and stable perovskite solar modules

Abstract

Poly(3-hexylthiophene) (P3HT) is one of the most promising hole-transporting materials in the pursuit of efficient and stable perovskite solar cells due to its outstanding stability and low cost. However, the intrinsic low carrier density of P3HT and poor contact between the P3HT/perovskite interface always lead to a low performance of the solar cell, while conventional chemical doping always makes the films unstable and limits the scalability. In this work, for the first time, we simultaneously enhanced the hole transporting properties of P3HT film and the interface of perovskite by doping it with a judiciously designed oxidized small molecule organic semiconductor. The organic salt not only can promote the lamellar crystallinity of P3HT to obtain better charge transport properties, but also reduce the defects of perovskite. As a result, we achieved champion efficiencies of 23.0% for small-area solar cells and 18.8% for larger-area modules (48.0 cm²). This efficiency is the highest value for P3HT-based perovskite modules. Moreover, the solar cells show excellent operational stability, retaining over 95% of their initial efficiencies after 1200 h of continuous operation.