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Second Harmonic Generation and Fluorescence of CMONS Dye Nanocrystals Grown in a Sol‐Gel Thin Film

2003; Wiley; Volume: 4; Issue: 7 Linguagem: Inglês

10.1002/cphc.200300681

1439-7641

François Treussart, Estelle Appert, Nguyêt‐Thanh Ha‐Duong, Alain Ibanez, Jean‐François Roch, Robert B. Pansu,

Protein Interaction Studies and Fluorescence Analysis

CMONS: an alternative to fluorescent probes? Nanocrystals of CMONS dye (see picture), about 100 nm in diameter, were grown in a sol-gel thin film. The authors selectively grew the non-centrosymmetric form in order to study the nanocrystals' nonlinear properties. Using scanning optical microscopy, the two-photon induced fluorescence and the second harmonic generation (SHG) signals. (shown) were simultaneously mapped. Time-resolved fluorescence spectroscopy on a single nanocrystal yielded an excited-state relaxation time that is about twenty times smaller than that of a microcrystal, taken as the reference for bulk. This can be explained by the photoinduced isomerization of the stilbene-like CMONS molecules localized at the surface of the nanocrystal.