Ultrafast coherence transfer in DNA-templated silver nanoclusters

Abstract

DNA-templated silver nanoclusters of a few tens of atoms or less have come into prominence over the last several years due to very strong absorption and efficient emission. Applications in microscopy and sensing have already been realized, however little is known about the excited-state structure and dynamics in these clusters. Here we report on a multidimensional spectroscopy investigation of the energy-level structure and the early-time relaxation cascade, which eventually results in the population of an emitting state. We find that the ultrafast intramolecular relaxation is strongly coupled to a specific vibrational mode, resulting in the concerted transfer of population and coherence between excited states on a sub-100 fs timescale.

First Step Towards Larger DNA-Based Assemblies of Fluorescent Silver Nanoclusters: Template Design and Detailed Characterization of Optical Properties

“…The complexity of AgNC optical properties is also manifested by the possibility of direct and indirect excitation: Directly in the visible spectral range or indirectly via UV-excitation of DNA bases [23]. The structure and nature of optically active electronic states are poorly understood [24,25]. Therefore, a detailed characterization of these effects is needed to establish how AgNC function in larger assemblies.…”

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

“…The OADF approach has been demonstrated so far only using DNA-stabilized silver nanoclusters (DNA-AgNCs) by taking advantage of their particular photophysical properties 9–11. DNA-AgNCs are a new class of emitters, first introduced by Petty et al in 2004 12,13. After excitation with visible light, DNA-AgNCs can enter a microsecond long-lived dark state 7,14–17.…”

Anti-Stokes fluorescence microscopy using direct and indirect dark state formation

“…27 All these initial processes are ultrafast and occur on a sub-picosecond timescale. [27][28][29] Generally, the quantum yield of dark state formation (Q D1 ) is in the order of a few percent, but values around 25% have been reported. [22][23][24][25] According to literature and in compliance with the phenomenological electronic state diagram in Fig.…”