Ternary polymer solar cells based-on two polymer donors with similar HOMO levels and an organic acceptor with absorption extending to 850 nm

Abstract

Abstract Ternary blending is an effective way to realize higher short circuit current density (Jsc) and higher power conversion efficiency (PCE) of the polymer solar cells (PSCs) by broadening and enhancing light harvests. In this work, we fabricated the ternary PSCs by using a narrow bandgap n-type organic semiconductor (n-OS) BT-IC with absorption edge extending to 850 nm as acceptor and two absorption-complementary conjugated polymer J51 and PTB7-Th with similar HOMO energy levels as donor. The ternary PSCs based on J51: PTB7-Th: BT-IC (0.5:0.2:1, w/w) without additive treatment demonstrated a higher PCE of 10.32% with a Voc of 0.79 V, a higher Jsc of 19.55 mA cm−2, and a FF of 67.0%. In addition, the morphology of the ternary blend active layer of the devices is quite stable after long-term thermal annealing at 130 °C.