Hole-transporting diketopyrrolopyrrole-thiophene polymers and their additive-free application for a perovskite-type solar cell with an efficiency of 16.3%

Abstract

Conjugated polymers of diketopyrrolopyrrole (DPP) and thiophene, especially 2,5-di-2-thienyl-thieno[3,2-b]thiophene, were characterized based on their molecular packing orientation, and they showed a π–π stacking distance of 3.6 Å and a high field-effect hole mobility on the order of 10−2 cm2/Vs. Perovskite solar cells fabricated with the genuine or both oxidant- and salt dopant-free polymer as the hole-transporting layer displayed high photoconversion efficiencies of 16.3% as well as high durability.