Luminescence and creation of electron-hole trapping centers in alkali metal sulfates activated by Pb2+ impurity

The nature of the impurity emission and the process of creating intrinsic and impurity electron-hole trapping centers were studied by spectroscopic and thermal activation methods in Na 2 SO 4 - Pb and K 2 SO 4 - Pb phosphors. The combined radiative electronic state is formed from intrinsic SO 3 − 4 - SO − 4 and impurity Pb + - SO − 4 electron-hole trapping centers in UV-irradiated phosphors with a photon energy of 6.2 eV at 80 K. Emissions of 3.2 eV and 3.6 eV resulting from irradiation with photons with an energy of 6.2 eV are associated with intracenter transitions of 3p 1 - 1s 0 in Pb 2 + located in nonequivalent positions of the Na 2 SO 4 lattice.