2022 article

A Benzo[1,2-b:4,5-b']Difuran Based Donor Polymer Achieving High-Performance (>17%) Single-Junction Organic Solar Cells with a Fill Factor of 80.4%

Yi, J., Pan, M., Chen, L., Chen, Y., Angunawela, I. C., Luo, S., … Yan, H. (2022, July 19). ADVANCED ENERGY MATERIALS.

By: J. Yi*, M. Pan*, L. Chen*, Y. Chen*, I. Angunawela n, S. Luo*, T. Zhang*, A. Zeng* ...

co-author countries: China 🇨🇳 Hong Kong 🇭🇰 United States of America 🇺🇸
author keywords: benzo[1,2-b:4,5-b']difuran; fill factors; morphology; organic solar cells; polymer donors
Source: Web Of Science
Added: July 26, 2022

Abstract In the field of non‐fullerene organic solar cells (OSCs), most of the promising polymer donors are based on benzo[1,2‐b:4,5‐b′]dithiophene (BDT) units while benzo[1,2‐b:4,5‐b′]difuran (BDF)‐based polymers have drawn less attention since the efficiencies of BDF polymer‐based devices are generally lower than those of BDT polymer‐based ones. In this contribution, the BDT unit in a polymer donor named D18 is replaced with a BDF unit, and a new polymer named D18‐Fu is synthesized. As a highly‐crystalline molecule named Y6‐1O is chosen as the acceptor, the efficiency of binary devices based on D18‐Fu can reach 16.38%. Furthermore, when one of fullerene derivatives PC 71 BM is added, the ternary devices based on D18‐Fu achieve an efficiency of 17.07% and a high fill factor (FF) of 80.4%, both of which are the highest values among those of BDF polymer‐based devices. For comparison, D18‐based ternary devices show an inferior efficiency of 15.61% mainly due to the lower FF of 73.9%. Subsequent characterization reveals that D18‐Fu possesses a more coplanar molecular geometry, leading to better morphology and higher charge mobility for a promising FF. The high performance shown in this work demonstrates the potential role of BDF units in the design of polymer donors for highly efficient OSCs.