文献类型：期刊文献

英文题名：Bidirectional Single-Molecule Photoconductors Based on ESIPT

作者：Qiu, Jin[1];Jiang, Shuyu[1];Zhang, Yutian[1];Qiao, Mengyuan[1];Wang, Rui[1];Chen, Xuanying[1];Zhang, Zhiyun[1];Zou, Qi[1];Tian, He[1]

机构：[1]East China Univ Sci & Technol, Frontiers Sci Ctr Materiobiol & Dynam Chem, Feringa Nobel Prize Scientist Joint Res Ctr,Inst F, Sch Chem & Mol Engn,Joint Int Res Lab Precis Chem, Shanghai 200237, Peoples R China

年份：2025

卷号：147

期号：47

起止页码：43371

外文期刊名：JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

收录：;EI(收录号：20254819599393);WOS:【SCI-EXPANDED(收录号:WOS:001616528100001)】；

基金：This work was supported by the National Natural Science Foundation of China (grants 22335004, 22588101, 22175064, 22475067, 22475068, 22405087, and 22405088), the Science and Technology Commission of Shanghai Municipality (grant 24DX1400200), and the Program of Introducing Talents of Discipline to Universities (grant B16017). The authors thanks Prof. Yaping Zang (Institute of Chemistry, Chinese Academy of Sciences) and Prof. Shimin Hou (Peking University) for their calculation guidance.

语种：英文

外文关键词：Excited states - Molecules - Orbital calculations - Photoconducting materials - Quantum theory - Scaffolds - Scaffolds (biology)

摘要：Single-molecule photoconductors capable of optically modulating molecular conductance hold great promise for molecular optoelectronics, yet challenges persist in modulating bidirectional photoconductance at the single-molecule level. Here we present a rational design strategy for high-performance single-molecule photoconductors exhibiting either increased or decreased photoconductance, enabled by the synergistic interplay between excited-state intramolecular proton transfer (ESIPT) and quantum interference (QI) effects. Utilizing the scanning tunneling microscope break junction (STM-BJ) technique, we investigate two structurally related 2-(2-hydroxyphenyl)pyridines with p- and m-SMe groups (PPOH and PMOH), achieving record-high photoconductance modulation. Upon continuous 365 nm irradiation, PPOH-based junctions exhibit the first inverse photoconductance with a remarkable similar to 120-fold decrease, among the most significant reported, while PMOH-based junctions show an similar to 1.78-fold enhancement, demonstrating bidirectional photoconductance within a shared molecular scaffold. Theoretical calculations reveal that in PPOH, ESIPT induces frontier orbital localization, which dominates over bandgap narrowing, leading to conductance suppression. In PMOH, in addition to these two factors, ESIPT drives a QI transition from destructive interference in the ground state to constructive interference upon photoexcitation, enhancing conductance. This work bridges macroscopic photoconductor materials and individual photoresponsive molecules, offering a new molecular design paradigm for ESIPT-driven QI effects.