Enhancing charge transport in an organic photoactive layer: Via vertical component engineering for efficient perovskite/organic integrated solar cells

Suitable vertical component distribution within an organic bulk-heterojunction (BHJ) is vital for effective exciton dissociation and smooth charge transport in perovskite/organic integrated solar cells (ISCs). Herein, a bi-continuous interpenetrating network of organic donor/acceptor materials is constructed simply by optimizing their weight ratio, and is further applied in perovskite/organic ISCs. Time-of-flight secondary-ion mass spectroscopy (TOF-SIMS) and scanning Kelvin probe microscopy (SKPM) strongly confirm that this method can effectively restrict vertical stratification and build a desired bi-continuous framework within the organic photoactive layer, which can effectively suppress two potential recombination losses from the viewpoint of kinetics, leading to the PCE increasing from 12.63% to 15.47% for ISCs based on the structure of MAPbI₃/PBDB-T:IEICO. Meanwhile, our ISCs combining a UV-vis harvesting layer of MAPbI₃ and a near-infrared absorbing layer of PBDB-T:IEICO exhibit a photo-response extending to the whole visible and infrared spectrum (up to 900 nm). This work verifies that tuning the donor/acceptor weight ratio is a feasible strategy for optimizing the morphology of BHJ absorbers and suppressing charge recombination for efficient perovskite/BHJ ISCs.