Employing PCBTDPP as an Efficient Donor Polymer for High Performance Ternary Polymer Solar Cells.

A compatible low-bandgap donor polymer (poly[N-90-heptadecanyl-2,7carbazole-alt-3,6-bis(thiophen-5-yl)-2,5-dioctyl-2,5-dihydropyrrolo [3,4] pyrrole-1,4-dione], PCBTDPP) was judicially introduced into the archetypal poly(3-hexylthiophene):[6,6]-phenyl-C-butyric acid methyl ester (P3HT:PCBM) photoactive system to fabricate highly efficient ternary based bulk heterojunction polymer solar cells (PSCs). The PCBTDPP ternary-based PSC with optimal loading (0.2 wt.%) displayed outstanding performance with a champion power conversion efficiency (PCE) of 5.28% as compared to the PCE (4.67%) for P3HT:PCBM-based PSC (reference). The improved PCE for PCBTDPP ternary-based PSC can be mainly attributed to the incorporation of PCBTDPP into P3HT:PCBM that beneficially improved the optical, morphological, electronic, and photovoltaic (PV) performance. This work instills a rational strategy for identifying components (donor/acceptor (D/A) molecules) with complementary beneficial properties toward fabricating efficient ternary PSCs.