Morphology Evolution via a Generic Solvent Additive Concept Enables Large‐Area All‐Polymer Solar Cells with Negligible PCE Loss

Abstract

AbstractSmall‐area all‐polymer solar cells (all‐PSCs) have obtained excellent power conversion efficiency (PCE) through smart design of materials and advanced device fabrication. Nevertheless, commercialization of all‐PSCs requires the urgent development of large‐area all‐PSCs processing techniques compatible with roll‐to‐roll processing. Generally, the PCE of all‐PSCs drops sharply with the increased device area, which is the biggest obstacle for fabrication of large‐area all‐PSCs toward commercialization. Morphology modulation of bulk heterojunction (BHJ) film may be an effective strategy for fabrication of large‐area all‐PSCs. In this work, a solvent additive 1,8‐diiodooctane (DIO) is introduced to regulate the charge transport, molecular orientation, and BHJ film morphology of all‐PSCs. As the device area of all‐PSCs expands from 0.04 to 0.5 cm2, the PCE of the device without DIO reduces by 14.8%, while that of the device with DIO only reduces by 3.3%. To the best of the authors’ knowledge, this is the lowest PCE attenuation value achieved for 0.5–1 cm2 all‐PSCs. The DIO solvent additive is also applicable to other efficient all‐PSCs, which proves the advance of generic solvent additive concept for constructing high‐performance large‐area all‐PSCs, and may push forward the commercialization process of all‐PSCs.