Herein, we demonstrate that the lifetimes of polymer-based solar cells comprising PTB7-F20: PC71BM composites can be significantly increased by using post-additive-soaked bulk heterojunction (BHJ) films. Analyses of solar cell performance, film morphology, time-resolved photoluminescence, and photoconductivity revealed that the above increase resulted from the combined effects of the improved carrier generation and transport in post-additive-soaked BHJ films and the efficient deactivation of burn-in loss by using the photochemically stable PTB7-F20 polymer. (C) 2017 Elsevier B.V. All rights reserved.