An intrinsic luminescence in binary lead silicate glasses

Abstract The low-temperature photoluminescence (PL) of x PbO · (1 − x )SiO 2 glasses ( x = 0.20–0.75) was studied at Т = 10 K. The recorded PL-spectra are a superposition of three spectral components with maxima located at 1.8 eV (identified as Pb 6 p → metal-bridging O2 p radiative electron transition, the “ R ”-band), 2.0 eV (Pb 6 p → non-bridging O2 p , the “ O ”-band) and 2.55 eV (Pb 6 p → Pb 6 s , the “ B ”-band), respectively. It was found the essential link for “ R ”, “ O ” and “ B ” PL-bands with chemical composition x of the glasses under study. These concentration dependences are expressed as mutual PL-intensity variations for each recorded luminescence band that allowed to determine their origin. The shape of established dependences well coincides with numerical data on NBO- and MBO-density of chemical bonding, reported previously. The overall PL-manner within the temperature range of 10–295 K is described by an empirical Street’s law. It was shown that experimental photoluminescence quenching curves may be precisely approximated as a superposition of Mott relationships for nonequivalent luminescence centers. The obtained distribution of PL-centers on the activation energy for luminescence quenching reflects the essential donation of the low-energy states into the overall PL-process. The width of this energy distribution affects by the type of PL-emission band and the disordering degree in the arrangement of local PL-centers of a certain kind.