On-Resonance Fluorescence, Resonance Rayleigh Scattering, And Ratiometric Resonance Synchronous Spectroscopy Of Molecular- And Quantum Dot-Fluorophores

Abstract

Existing studies on molecular fluorescence have almost exclusively been focused on Stokes-shifted fluorescence spectroscopy (SSF) in which the emitted photon is detected at the wavelengths longer than that for the excitation photons. Information on fluorophore on-resonance fluorescence (ORF) and resonance Rayleigh scattering (RRS) is limited and often problematic due to the complex interplay of the fluorophore photon absorption, ORF emission, RRS, and solvent Rayleigh scattering. Reported herein is a relatively large-scale systematic study on fluorophore ORF and RRS using the conventional UV-vis extinction and SSF measurements in combination with the recently reported ratiometric resonance synchronous spectroscopic (R2S2, pronounced as "R-Two-S-Two") method. A series of fundamental parameters including fluorophore ORF cross sections and quantum yields have been quantified for the first time for a total of 12 molecular and 6 semiconductor quantum dot (QD) fluorophores. All fluorophore spectra comprise a well-defined Gaussian peak with a full width at half-maximum ranging from 4 to 30 nm. However, the RRS features of fluorophores differ drastically. The effect of fluorophore aggregation on its RRS, UV-vis, R2S2, and SSF spectra was also discussed. This work highlights the critical importance of the combined UV-vis extinction, SSF, and R2S2 spectroscopic measurements for material characterizations. The method and insights described in this work can be directly used for improving the reliability of RRS spectroscopic methods in chemical analysis. In addition, it should pave the way for developing novel R2S2-based analytical applications.

Publication Date

9-20-2016

Publication Title

Analytical Chemistry

Volume

88

Issue

18

Number of Pages

9199-9206

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1021/acs.analchem.6b02420

Socpus ID

84988484320 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84988484320

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