Disentangling optically activated delayed fluorescence and upconversion fluorescence in DNA stabilized silver nanoclusters.

Stefan Krause,Tom Vosch,Cecilia Cerretani

doi:10.1039/c9sc00865a

Stefan Krause, Tom Vosch + Show 1 more

Open Access

https://doi.org/10.1039/c9sc00865a

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Abstract

Optically activated delayed fluorescence (OADF) is a powerful tool for generating background-free, anti-Stokes fluorescence microscopy modalities. Recent findings, using DNA-stabilized silver nanoclusters (DNA-AgNCs), indicate that OADF is usually accompanied by a dark state-mediated consecutive photon absorption process leading to upconversion fluorescence (UCF). In this study, we disentangle the OADF and UCF process by means of wavelength-dependent NIR excitation spectroscopy. We demonstrate that, by appropriate choice of secondary NIR excitation wavelength, the dark state population can be preferentially depleted through OADF, minimizing the UCF contribution. These findings show that dark state depletion by OADF might enable background-free STED-like nanoscopy.

Highlights

Auto uorescence of tissues and cells is a common problem in uorescence microscopy, as it can compete with the uorescence signal of interest or complicate signal quanti cation
Recent findings, using DNA-stabilized silver nanoclusters (DNA-AgNCs), indicate that Optically activated delayed fluorescence (OADF) is usually accompanied by a dark state-mediated consecutive photon absorption process leading to upconversion fluorescence (UCF)
By appropriate choice of secondary NIR excitation wavelength, the dark state population can be preferentially depleted through OADF, minimizing the UCF contribution

Summary

Introduction

Auto uorescence of tissues and cells is a common problem in uorescence microscopy, as it can compete with the uorescence signal of interest (e.g. in single molecule studies) or complicate signal quanti cation.

Results

Conclusion