Luminescence of the Lead Dimer Center in SrS and SrSe Phosphors

Abstract

Emission and excitation spectra of the SrS and SrSe phosphors containing high concentrations of Pb²⁺ ions are measured at low temperatures. Green emission bands due to the Pb²⁺ dimer centers are observed at 530 nm for SrS: Pb²⁺ and at 500 nm for SrSe: Pb²⁺ at 80 K in addition to the UV emission bands due to the Pb²⁺ monomer centers. Seven bands ascribed to the Pb²⁺ dimer centers are found in the excitation spectra of the green emission bands. The values of the parameters appearing in the energy matrices of the dimer center are determined so that the calculated electronic levels coincide with the experimental excitation energies of the seven bands.