Cost-Effective Perylene-Diimide Non-Conjugated Polymer as Cathode Interlayer for Large-Scale Production of Organic Photovoltaics.

At present, organic solar cells (OSCs) stand at a key stage of industrialization. Although many organic photovoltaic materials exhibit outstanding performance, they cannot meet the requirements for large-scale production. Here, a cost-effective and high-throughput method is reported to prepare Perylene/naphthalene-diimide (PDI/NDI) non-conjugated polymers for serving as cathode interlayer (CIL) materials in OSCs. By utilizing low-cost raw materials, the NDI/PDI polymers can be readily synthesized without involving purification by column chromatography, which minimizes the cost of CILs. Notably, the performance of PDI-OEG CIL is insensitive to preparation conditions and processing methods, thereby lowering the technical threshold for practical applications, which is essentially important for large-scale production. By using a binary blend PM6:L8-BO as an active layer, the OSC modified by PDI-OEG exhibited a power conversion efficiency (PCE) of 18.7%. It is demonstrated that the suitable work function, self-doping effect, and H-aggregate endowed PDI-OEG with excellent electron collection capability, which can suppress the charge recombination in OSCs. Moreover, PDI-OEG is well-compatible with a large-area blade-coating technique, and a 1-cm OSC can be fabricated by using a blade-coated PDI-OEG, delivering a PCE of 17.0%. The results suggest that PDI-OEG is a promising CIL material for advancing the industrialization of organic photovoltaic technology.