中国科学院理化技术研究所王健君团队的一项最新研究实现高效对称破缺电荷分离和输运的超小有机纳米晶光催化剂。这一研究成果于2025年4月7日发表在国际顶尖学术期刊《美国化学会杂志》上。

受天然光系统II中对称破断电荷分离（SBCS）的启发，研究人员采用冻结组装（FA）策略将对称的苝二亚胺（PDI）二聚体组装成具有有序分子堆叠的超小（亚5 nm）纳米晶体（NCs），表现出SBCS的特征。与非SBCS NCs （PDI-5 nm）相比，SBCS NCs （p-5 nm）的电荷分离效率提高了12.3倍。

此外，p-5 nm的电荷转移效率（94.7%）是弱SBCS NCs （m-5 nm, 60.4%）的1.6倍。结果表明，PDI基光催化剂在p-5 nm的光催化析氢速率为1824 μmol h^-1 g^-1。本研究强调了超小型NCs在实现生物启发SBCS方面的重要性，以及FA策略在开发高性能OPCs方面的潜力。

研究人员表示，有机光催化剂（OPCs）的高激子结合能和短激子扩散长度（典型的5-10 nm）阻碍了有效的电荷分离和随后的电荷转移，限制了其太阳能转换的潜力。

附：英文原文

Title: Ultrasmall Organic Nanocrystal Photocatalyst Realizing Highly Efficient Symmetry Breaking Charge Separation and Transport

Author: Junqiang Mao, Qingrui Fan, Zequan Yan, Xiaoran Chen, Shuai Zhao, Youhua Lu, Shasha Li, Wei Jiang, Zihao Xu, Zhaohui Wang, Jianjun Wang

Issue&Volume: April 7, 2025

Abstract: The high exciton binding energy and short exciton diffusion length (typical 5–10 nm) of organic photocatalysts (OPCs) hinder efficient charge separation and subsequent charge transfer, limiting their potential for solar energy conversion. Inspired by the symmetry breaking charge separation (SBCS) in natural photosystem II, we employed a freeze assembly (FA) strategy to assemble symmetric perylene diimide (PDI) dimers into ultrasmall (sub-5 nm) nanocrystals (NCs) with ordered molecular stacking, exhibiting SBCS characteristics. The SBCS NCs (p-5 nm) showed 12.3-fold enhancement in charge separation efficiency compared to non-SBCS NCs (PDI-5 nm). Furthermore, the charge transfer efficiency in p-5 nm (94.7%) was 1.6 times greater than that of weak SBCS NCs (m-5 nm, 60.4%). Consequently, we achieved a comparable photocatalytic hydrogen evolution rate (1824 μmol h–1 g–1) among the PDI-based photocatalysts in p-5 nm. This study highlights the importance of ultrasmall NCs in fulfilling bioinspired SBCS and the potential of the FA strategy for developing high-performance OPCs.

DOI: 10.1021/jacs.5c01205

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.5c01205