Dithienoquinoxalineimide‐Based Polymer Donor Enables All‐Polymer Solar Cells Over 19 % Efficiency

All-polymer solar cells (all-PSCs) have been regarded as one of the most promising candidates for commercial applications owing to their outstanding advantages such as mechanical flexibility, light weight and stable film morphology. However, compared to large amount of new-emerging excellent polymer acceptors, the development of high-performance polymer donor lags behind. Herein, a new D-π-A type polymer donor, namely QQ1, was developed based on dithienoquinoxalineimide (DTQI) as the A unit, benzodithiophene with thiophene-conjugated side chains (BDTT) as the D unit, and alkyl-thiophene as the π-bridge, respectively. QQ1 not only possesses a strong dipole moment, but also shows a wide band gap of 1.80 eV and a…