福州大学汪颖团队的一项最新研究发现了紧密的π-π堆叠促进了光催化制氢的苝单亚胺分子间电荷分离。这一研究成果于2025年3月31日发表在国际顶尖学术期刊《结构化学》上。

超分子有机半导体中π-π堆积的紧密性对光生载流子的空间分离和迁移动力学起着至关重要的作用，最终决定了它们的光催化性能。为了实现π-π的紧密堆积，分子结构的合理设计至关重要。为此，设计合成了吡啶羧酸修饰过二烯单亚胺（PMI）的两个异构体PM5A和PM6A。在水溶液中，这些分子自组装成聚集体，表现出明显的堆叠性质和光学特性。在光激发下，PM5A松散的π-π堆叠有利于产生电荷转移激子（cte）而不是电荷分离激子（cse）。相比之下，PM6A通过分子间氢键稳定，具有紧密的π-π堆叠，在4.5皮秒内进行有效的电荷分离，产生CSEs。Pt/PVP/PM6A体系的析氢速率为8100 μmol·g^-1·h^-1，是Pt/PVP/PM5A体系的近5倍。此外，在λ = 425 nm单波长光照射下，最大表观量子效率（AQE）达到约2.1%。

附：英文原文

Title: Close π-π stacking facilitated intermolecular charge separation in self-assembled perylene monoimide for photocatalytic hydrogen production

Author: anonymous

Issue&Volume: 2025-03-31

Abstract: The tightness of π-π stacking in supramolecular organic semiconductors plays a crucial role in governing the spatial separation and migration dynamics of photogenerated charge carriers, ultimately determining their photocatalytic performance. To achieve close π-π stacking, the suitable design of molecular structure is essential. Therefore, two isomers of pyridine carboxylic acid-modified perylene monoimide (PMI) were designed and synthesized, namely PM5A and PM6A. In aqueous solution, these molecules self-assemble into aggregates, which exhibit distinct stacking properties and optical characteristics. Upon photoexcitation, the loose π-π stacking of PM5A favors the generation of charge transfer excitons (CTEs) over charge separation excitons (CSEs). In contrast, PM6A, stabilized by intermolecular hydrogen bonds and possessing close π-π stacking, undergoes efficient charge separation to produce CSEs within 4.5 picoseconds. When incorporated into metal-insulator-semiconductor (MIS) photosystems with polyvinylpyrrolidone (PVP)-capped Pt, the Pt/PVP/PM6A system demonstrates a hydrogen evolution rate of 8100 μmol·g^-1·h^-1, nearly five times higher than that of the Pt/PVP/PM5A system. Additionally, the maximum apparent quantum efficiency (AQE) reaches approximately 2.1% under irradiation with light of a single wavelength of λ = 425 nm.

DOI: 10.1016/j.cjsc.2025.100592

Source: http://cjsc.ac.cn/cms/issues/785