Toward efficient non-fullerene polymer solar cells: Selection of donor polymers

Abstract

Recently, perylene bisimides have been explored and developed as potential candidates for non-fullerene acceptors and power conversion efficiencies (PCEs) exceeding 3% were realized in the non-fullerene polymer solar cells (NF-PSCs) featuring perylene bisimides as acceptors. Considering that only a few donor polymers like P3HT and PBDTTT-C-T were utilized in non-fullerene PSCs, screening donor polymers with well-matched energy levels, absorption spectrum as well as hole mobility in NF-PSCs will be the key to promote the current PCEs. Herein, four high performance donor polymers including PBDTTPD, PBDTTT-EFT, PDPP3T, PSBTBT were employed for the optimization of single bond-linked perylene bisimide (SDIPBI)-based NF-PSCs. A clear criterion in selection of donor polymers has been established for the SDIPBI-based NF-PSCs. Suitable energy level differences, finer morphology, and broad absorption ranges could be successively screened for donor polymers. Interestingly, NF-PSCs based on PBDTTPD/SDIPBI delivers a high Voc of 1.04V and a desirable PCE of 3.4%. Moreover, the SDIPBI-based NF-PSC employing PBDTTT-EFT as donor polymer exhibits a high PCE up to 4.5%. The results implicate that to select donor polymers is a feasible strategy to boost the photovoltaic performance of NF-PSCs further.