High-Quality Polymeric Precision through Stepwise Stille Polycondensation toward No Batch-to-Batch Variations in Polymer Solar Cell

Abstract

Using a stepwise-heating protocol in the Stille polycondensation in conjunction with optimized processing, we obtained an ultrahigh-quality PTB7 polymer having high Mw and very narrow Ð. The resulting ultrahigh-quality polymer-based solar cells demonstrate up to 9.97% power conversion efficiencies (PCEs), which is over 24% enhancement from the control devices fabricated with commercially available PTB7. Moreover, we observe almost negligible batch-to-batch variations in the overall PCE values from ultrahigh-quality polymer-based devices. The proposed stepwise polymerization demonstrates a facile and effective strategy for synthesizing high-quality semiconducting polymers that can significantly improve device yield in polymer-based solar cells, an important factor for the commercialization of organic solar cells, by mitigating device-to-device variations.