Enhanced efficiency of ternary organic solar cells by doping a polymer material in P3HT:PC61BM

Doping a low‐bandgap polymer material (PDTBDT‐DTNT) as a complementary electron donor in poly(3‐hexylthiophene) (P3HT) and [6,6]‐phenyl‐C61‐butyricacid methyl ester (PC61BM) blend is experimented to improve the power conversion efficiency (PCE) of organic solar cells (OSCs). The PCE of OSCs was increased from 3.19% to 3.75% by doping 10 wt% PDTBDT‐DTNT, which was 17.55% higher than that of the OSCs based on binary blend of P3HT:PC61BM (host cells). The short‐circuit current density (Jsc) was increased to 10.11 mA·cm−2 compared with the host cells. Although the PCE improvement could partly be attributed to more photon harvest for complementary absorption of 2 donors by doping appropriate PDTBDT‐DTNT, the promotion of charge separation and transport as well as the suppression of charge recombination due to a matrix of cascade energy levels is also important. And the better morphology of the active layer films is beneficial to the optimized performance of ternary devices. Doping PDTBDT‐DTNT as a complementary electron donor in P3HT and PC61BM blend is experimented to improve the power conversion efficiency of organic solar cells. The PCE of ternary OSCs and the short‐circuit current density were increased obviously compared with the binary cells. More photon harvest for complementary absorption of two donors, the promotion of charge separation, the suppression of charge recombination, and the better morphology of the active layer films are beneficial to the optimized performance of ternary devices.