Novel dithieno[3,2-f:2',3'-h]quinoxaline-based polymers as hole transport materials for perovskite solar cells

Two novel conjugated polymers comprised of 2,3-R₂-di- thieno[3,2-f:2’,3’-h]quinoxaline, where R is 3’-(octyloxy)- phenyl (P1) or 2’-(2-ethylhexyl)thiophen-4’-yl (P2), and 2,1,3-benzothiadiazole have been synthesized using the Stille cross-coupling reaction. The synthesized polymers were investigated as hole transport layer (HTL) materials in perovskite solar cells. Polymer P2 as an HTL material provided improved short-circuit current and open-circuit voltage and, correspondingly, enhanced power conversion efficiency of perovskite solar cells compared to that of polymer P1.