Reversing Surface Charge for Highly‐Active Organic Photovoltaic Catalysts
Shichao Wu, Zhenzhen Zhang, Yuhsuan Lee, Yawen Li, Xuefeng Tai, Wenqin Si, Shuming Bai, Yuze Lin
Abstract
Abstract Organic photovoltaic materials typically exhibit low charge separation and transfer efficiency and severe exciton/carrier recombination due to high exciton binding energy and short exciton diffusion lengths, limiting the enhancement of photocatalytic hydrogen evolution performance. Here, we introduce a surface charge reversal strategy to regulate the charge character of organic photovoltaic catalyst (OPC). Compared to OPC nanoparticles (NPs) stabilized by an anionic surfactant ((−) NPs), NPs stabilized by a cationic surfactant ((+) NPs) exhibit a raised Fermi level, larger surface band bending and Schottky barrier, thereby enhancing charge separation and transfer efficiency while suppressing charge carrier recombination. As a result, (+) NPs demonstrate better photocatalytic performance than (−) NPs, independent of the chemical structure of OPCs and surfactant molecules. Under the illumination of AM1.5G, 100 mW cm −2 , the PM6: 2FBP‐4F NPs stabilized by cationic surfactant (dodecyltrimethylammonium bromide, DTAB) exhibit much higher photocatalytic activity for hydrogen evolution (up to 946.1±15.76 mmol h −1 g −1 ) than that of PM6: 2FBP‐4F NPs stabilized by anionic surfactant, among the best results reported so far for photocatalytic hydrogen evolution under simulated sunlight.