A DNA-Stabilized Ag1812+ Cluster with Excitation-Intensity-Dependent Dual Emission
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DNA-stabilized silver nanoclusters (DNA-AgNCs) are easily tunable emitters with intriguing photophysical properties. Here, a DNA-AgNC with dual emission in the red and near-infrared (NIR) regions is presented. Mass spectrometry data showed that two DNA strands stabilize 18 silver atoms with a nanocluster charge of 12+. Besides determining the composition and charge of DNA2[Ag18]12+, steady-state and time-resolved methods were applied to characterize the picosecond red fluorescence and the relatively intense microsecond-lived NIR luminescence. During this process, the luminescence-to-fluorescence ratio was found to be excitation-intensity-dependent. This peculiar feature is very rare for molecular emitters and allows the use of DNA2[Ag18]12+ as a nanoscale excitation intensity probe. For this purpose, calibration curves were constructed using three different approaches based either on steady-state or time-resolved emission measurements. The results showed that processes like thermally activated delayed fluorescence (TADF) or photon upconversion through triplet-triplet annihilation (TTA) could be excluded for DNA2[Ag18]12+. We, therefore, speculate that the ratiometric excitation intensity response could be the result of optically activated delayed fluorescence.
Originalsprog | Engelsk |
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Artikelnummer | e202309760 |
Tidsskrift | Angewandte Chemie - International Edition |
Vol/bind | 62 |
Udgave nummer | 39 |
ISSN | 1433-7851 |
DOI | |
Status | Udgivet - 2023 |
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© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.
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