Interfacial π···π-Hole Interactions Regulate Exciton Evolution for Long-Lived Charge-Separated States and Efficient Photocatalytic Hydrogen Production

Regulating the exciton evolution behavior of linear conjugated polymers and constructing efficient exciton cascade evolution pathways to convert their dominant nonradiative recombination into long-lived charge-separated (CS) states remains a significant challenge. We propose a viable strategy centered on engineering interfacial π···π-hole interactions to modulate the exciton evolution processes and achieve long-lived CS states. Specifically, by compositing the poly(3,4-dimethoxythiophene- alt -4,7-dithienyl-2,1,3-benzothiadiazole) (PDB) with graphitic carbon nitride (CN), we fabricated 2D/2D PDB/CN heterojunctions with interfacial π···π-hole interactions. It is proven that the interfacial π···π-hole interactions not only regulate the exciton evolution pathways but also construct efficient charge transport channels, achieving long-lived CS states and excellent photocatalytic hydrogen production performance. Femtosecond and nanosecond transient absorption (fs-TA/ns-TA) spectroscopy analysis demonstrates that these interactions can accelerate the evolution of localized excitons (LE) to charge-transfer excitons (CT), suppress nonradiative recombination, and promote the conversion of CT states to long-lived CS states. This work reveals the crucial role of interfacial π···π-hole interactions in achieving long-lived CS states and provides important theoretical and experimental support for advancing the practical application of polymer photocatalysts.