文献类型：期刊文献

英文题名：Thermodynamic and Kinetic Control of π-Stacked Dimer Conductance in Single-Molecule Junctions

作者：Liu, Xin[1,2];Zhao, Yin[1,2];Li, Chenming[1,2];Li, Hongxiang[1,2]

机构：[1]East China Univ Sci & Technol, Feringa Nobel Prize Scientist Joint Res Ctr, Frontiers Sci Ctr Materiobiol & Dynam Chem, Sch Chem & Mol Engn,Inst Fine Chem,Key Lab Adv Mat, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Feringa Nobel Prize Scientist Joint Res Ctr, Frontiers Sci Ctr Materiobiol & Dynam Chem, Sch Chem & Mol Engn,Inst Fine Chem,Joint Int Res L, Shanghai 200237, Peoples R China

年份：2026

卷号：17

期号：27

起止页码：7575

外文期刊名：JOURNAL OF PHYSICAL CHEMISTRY LETTERS

收录：;EI(收录号：20262821088131);Scopus(收录号：2-s2.0-105044298747);WOS:【SCI-EXPANDED(收录号:WOS:001801544100001)】；

基金：This work was supported by the National Natural Science Foundation of China (52273176, 22575084), Fundamental Research Funds for the Central Universities, and East China University of Science and Technology.

语种：英文

外文关键词：Carrier transport - Charge transfer - Design for testability - Dimers - Kinetics - Scanning tunneling microscopy - Spurious signal noise - Thermodynamic stability

摘要：Understanding how pi-stacked dimers modulate charge transport is pivotal for molecular and supramolecular electronics. While extensive efforts have focused on transient, kinetically trapped dimers, thermodynamically stable pi-dimers-equally essential for the evolution of molecular and supramolecular electronics-remain insufficiently investigated. Herein, we investigate distinct conductance features of these two dimeric states using donor-acceptor-donor diketopyrrolopyrrole molecular wires. Correlating scanning tunneling microscope break-junction measurements, flicker-noise analysis, concentration-dependent UV-vis spectroscopy, and DFT-NEGF calculations, we show that at 1.0 mM, DPP-1Th yields predominantly monomeric junctions, together with a low-conductance feature consistent with a kinetically generated pi-dimer. Conversely, DPP-3Th shows evidence of preassembly into thermodynamically stable pi-dimers at concentrations exceeding 0.5 mM. Notably, the thermodynamically equilibrated DPP-3Th dimer exhibits a longer junction displacement yet enhanced conductance relative to the DPP-1Th low-conductance state, indicative of superior pi-orbital overlap and more efficient coupling pathways in the preorganized architecture. These results support distinct charge-transport characteristics for thermodynamically stable pi-dimers and kinetically generated pi-dimer. This work helps clarify an important ambiguity in supramolecular junction analysis and provides useful design guidelines for engineering aggregation-controlled charge transport in supramolecular electronic components.