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Electron Transfer at the Single‐Molecule Level in a Triphenylamine–Perylene Imide Molecule
Author(s) -
Bell Toby D. M.,
Stefan Alina,
Masuo Sadahiro,
Vosch Tom,
Lor Marc,
Cotlet Mircea,
Hofkens Johan,
Bernhardt Stefan,
Müllen Klaus,
van der Auweraer Mark,
Verhoeven Jan W.,
De Schryver Frans C.
Publication year - 2005
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200400567
Subject(s) - triphenylamine , perylene , chemistry , photochemistry , fluorescence , quantum yield , imide , molecule , acceptor , electron transfer , ground state , photoinduced electron transfer , atomic physics , organic chemistry , physics , quantum mechanics , condensed matter physics
Photoinduced electron transfer (ET) processes in a donor–acceptor system based on triphenylamine and perylene imide have been studied at the single‐molecule (SM) and ensemble levels. The system exists as two isomers, one of which undergoes forward and reverse ET in toluene with decay constants of 3.0 and 2.2 × 10 9 s −1 , respectively, resulting in the dual emission of quenched and delayed fluorescence while the other isomer remains ET‐inactive. The fluorescence of both isomers is heavily quenched in the more polar solvent, diethyl ether, by ET. A broad range of ET dynamics is seen at the SM level in polystryene with the two isomers nonresolvable indicating that the local nanoenvironment of the SMs varies considerably throughout the polymer matrix. Both the electronic coupling and the driving force for ET are shown to influence the ET dynamics. Many fluorescence trajectories of SMs show long periods (tens of milliseconds to seconds) where the count rate is attenuated either partly (a “dim” state) or to the background level (an “off‐time”). During these periods, the reduction or interruption of emission is attributed to cycles of rapid charge separation followed by charge recombination to the ground state reducing the fluorescence quantum yield of the SM.