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Controlling Plasmon‐Enhanced Fluorescence via Intersystem Crossing in Photoswitchable Molecules
Author(s) -
Wang Mingsong,
Hartmann Gregory,
Wu Zilong,
Scarabelli Leonardo,
Rajeeva Bharath Bangalore,
Jarrett Jeremy W.,
Perillo Evan P.,
Dunn Andrew K.,
LizMarzán Luis M.,
Hwang Gyeong S.,
Zheng Yuebing
Publication year - 2017
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201701763
Subject(s) - intersystem crossing , plasmon , fluorescence , photochemistry , materials science , molecule , quantum yield , merocyanine , chemistry , nanotechnology , photochromism , optoelectronics , excited state , optics , physics , organic chemistry , singlet state , nuclear physics
By harnessing photoswitchable intersystem crossing (ISC) in spiropyran (SP) molecules, active control of plasmon‐enhanced fluorescence in the hybrid systems of SP molecules and plasmonic nanostructures is achieved. Specifically, SP‐derived merocyanine (MC) molecules formed by photochemical ring‐opening reaction display efficient ISC due to their zwitterionic character. In contrast, ISC in quinoidal MC molecules formed by thermal ring‐opening reaction is negligible. The high ISC rate can improve fluorescence quantum yield of the plasmon‐modified spontaneous emission, only when the plasmonic electromagnetic field enhancement is sufficiently high. Along this line, extensive photomodulation of fluorescence is demonstrated by switching the ISC in MC molecules at Au nanoparticle aggregates, where strongly enhanced plasmonic hot spots exist. The ISC‐mediated plasmon‐enhanced fluorescence represents a new approach toward controlling the spontaneous emission of fluorophores near plasmonic nanostructures, which expands the applications of active molecular plasmonics in information processing, biosensing, and bioimaging.