Spontaneous vertical phase distribution of multi-acceptors system enables high-efficiency organic photovoltaics in non-halogenated solvent and large-area module application

Abstract

Building a vertical phase distribution morphology with a simple method is the critical key for high-efficiency organic photovoltaics (OPVs) and their industrial application. Here, OPVs based on a quaternary system with one donor PM6 and three acceptors (L8-BO, BTP-S8, and BTP-S2) were fabricated. The L8-BO-based blend was demonstrated to show unique vertical phase distribution (acceptors enriched on the top surface), leading to an exquisite morphology and superior carrier behaviors, thus power conversion efficiencies (PCEs) of 19.19% (certified as 19.18%) and 19.04% were achieved for chloroform-processed and toluene-processed devices, respectively. The high efficiency obtained from greener solvent is encouraging for commercialization of OPVs. Notably, the device processed with toluene without any additives shows a PCE of 17.28% with good stability, and the upscaled large-area module with a total area of 72.25 cm2 processed in air presents an outstanding PCE of 12.78%. This work provides valuable insights into the fabrication of greener solvent and large-area module OPVs.