Search

We report the chemistry and photophysics of atomic gold and silver particles in inorganic glasses. By synchrotron irradiation of gold-doped soda-lime silicate glasses we could create and identify unambiguously the gold dimer as a stable and bright luminescing particle embedded in the glassy matrix. The gold dimer spectra coincide perfectly with rare gas matrix spectra of Au2. The glass matrix is, however, stable for years, and is hence perfectly suited for various applications. If the irradiated gold-doped sample is annealed at 550 °C a bright green luminescence can be recognized. Intense 337 nm excitation induces a decrease of the green luminescence and the reappearance of the 753 nm Au2 emission, indicating a strong interrelationship between both luminescence centers. Time-dependent density functional theory (TD-DFT) calculations indicate that the green luminescence can be assigned to noble metal dimers bound to silanolate centers. These complexes are recognized as the first stages in the further cluster growth process, which has been investigated with small-angle x-ray scattering (SAXS). In silver-doped glasses, Ag0 atoms can be identified with electron paramagnetic resonance (EPR) spectroscopy after synchrotron activation. Annealing at 300 °C decreases the concentration of Ag1, but induces an intense white light emission with 337 nm excitation. The white luminescence can be decomposed into bands that are attributed to small silver clusters such as Ag2, Ag3 and Ag4, and an additional band matching the green emission of gold-doped glasses. [ABSTRACT FROM AUTHOR]