Controlling Plasmon-Enhanced Fluorescence via Intersystem Crossing in Photoswitchable Molecules

Mingsong Wang, Gregory Hartmann, Zilong Wu, Leonardo Scarabelli, Bharath Bangalore Rajeeva, Jeremy W. Jarrett, Evan P. Perillo, Andrew K. Dunn, Luis M. Liz-Marzán, Gyeong S. Hwang, Yuebing Zheng

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


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.

Original languageEnglish
Article number1701763
Issue number38
StatePublished - 11 Oct 2017

Bibliographical note

Publisher Copyright:
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


  • intersystem crossing
  • photoswitchable molecules
  • plasmon-enhanced fluorescence
  • plasmonic nanostructures
  • spiropyran


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