Tuning the electronic structure of a rod-like DNA-stabilized silver nanocluster Ag28Cl2 for photophysics in the NIR-II window†

Abstract

DFT calculations predict that photophysics of DNA-stabilized silver cluster can be tuned by controlling the oxidation state. The results show that the position and shape of the first absorption band depend dramatically on the total number of delocalized metal electrons in the silver core, varying from a well-defined peak around 755 nm to a broad band between 1100 and 1400 nm by a change of only four electrons. The photophysics can be straightforwadly explained by analysing the frontier orbitals that show a particle-in-a-box character. This predicted sensitivity of the photophysical properties to the oxidation state is relevant for considering the performance of DNA-stabilized silver clusters in NIR-II biological imaging.