Indene−C60Bisadduct: A New Acceptor for High-Performance Polymer Solar Cells

Abstract

Polymer solar cells (PSCs) are commonly composed of a blend film of a conjugated polymer donor and a soluble C₆₀ derivative acceptor sandwiched between an ITO anode and a low-workfunction metal cathode. Poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM) are the most widely used donor and acceptor materials, respectively. However, the low LUMO energy level of PCBM limits the open circuit voltage (V_oc) of the P3HT-based PSCs to ca. 0.6 V. Here we synthesized a new soluble C₆₀ derivative, indene−C₆₀ bisadduct (ICBA), with a LUMO energy level 0.17 eV higher than that of PCBM. The PSC based on P3HT with ICBA as acceptor shows a higher V_oc of 0.84 V and higher power conversion efficiency (PCE) of 5.44% under the illumination of AM1.5, 100 mW/cm², while the PSC based on P3HT/PCBM displays a V_oc of 0.58 V and PCE of 3.88% under the same experimental conditions. The results indicate that ICBA is an alternative high-performance acceptor and could be widely used in high-performance PSCs.