Optimization of the photovoltaic performance of all-polymer solar cells (all-PSCs) includes delicate control of the film morphology of the light-harvesting layer. Although miscibility of polymer donors and polymer acceptors plays a critical role in the description of film morphology of all-PSCs, the mixing thermodynamics is unrevealed. Herein, we demonstrate that by incorporating 1% weight ratio of PC71BM as the solid additive into the blends of electron-donating polymer PTzBI-oF and electron-accepting polymer PFA1, the miscibility of donor/acceptor can be improved by virtue of forming a favor...
