Enhanced solar cell performance by replacing benzodithiophene with naphthodithiophene in diketopyrrolopyrrole-based copolymers.

Replacing benzodithiophene (BDT) with a naphthodithiophene (NDT) building block, PNDTDPP exhibited enhanced photovoltaic performance with a PCE of 5.37% when compared with BDT-based copolymer PBDDPP, which gave a PCE of 2.91% in conventional device structures. Encouragingly, the obtained inverted PSC with PBDDPP achieved an impressively high PCE of 6.92%.