An intrinsic luminescence in binary lead silicate glasses

The low-temperature photoluminescence (PL) of xPbO · (1 − x)SiO2 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 6p → metal-bridging O2p radiative electron transition, the “R”-band), 2.0 eV (Pb 6p → non-bridging O2p, the “O”-band) and 2.55 eV (Pb 6p → Pb 6s, 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.

► The photoluminescence (PL) of PbO–SiO2 glasses at Т = 10 K was studied.
► PL-spectra contain three bands originating from intrinsic localized states in the energy band-gap.
► PL temperature quenching within range of 10–295 K is described by Street’s law.
► The calculations of PL-centers distribution depending on the quench activation energy are presented.