Tailoring block copolymer-type compatibilizers to enhance the performance and processability of inverted all-polymer solar cells

Abstract

This study reports a compatibilization strategy that improves the performance and processability of inverted all-polymer solar cells (all-PSCs) by incorporating block copolymer-type compatibilizers into the PM6 : PYIT-based bulk heterojunction layer. Surprisingly, adding just 1 wt% of the acceptor–acceptor block copolymer, PNDI2T-b-PYIT, as a compatibilizer resulted in a power conversion efficiency of 17.44%, outperforming the control device (16.72%). Even after prolonged stirring of the precursor solution, this additive exhibited superior morphology and performance. The compatibilizer improves the overall miscibility of the bulk heterojunction, promotes face-on molecular orientation, and balances charge transport, thereby reducing trap density and suppressing charge recombination. This work highlights the potential of using structurally tailored block copolymers to optimize the morphology and processability of all-PSCs.