On the photophysics of electrochemically generated silver nanoclusters: spectroscopic and theoretical characterization

Abstract

Ligand-free atomic silver nanoclusters (AgNCs) were successfully synthesized following the electrochemical procedure developed by Lopez-Quintela and col. (D. Buceta, N. Busto, G. Barone, J. M. Leal, F. Domínguez, L. J. Giovanetti, F. G. Requejo, B. García and M. A. López-Quintela, Angew. Chem., Int. Ed., 2015, 54, 7612–7616), who have identified the presence of Ag₂ and Ag₃ AgNCs. The goal of this work was to get information on the photophysics of these AgNCs, which was achieved by combining information from excitation/emission matrix (EEM) and time resolved emission spectroscopy (TRES) along with DFT/TD-DFT calculations. This procedure allowed deconvolving the emission and excitation spectra of the AgNC mixture, with further assignment of each transition and lifetime associated to Ag₂, Ag₃⁺ and Ag₄²⁺ clusters. This deconvolution together with theoretical calculations allowed suggesting for the first time the radiative and non-radiative excited state deactivation mechanism for these clusters.