Mechanisms of intrinsic and impurity electron-hole trapping centers in K_3 Y〖(SO_4)〗_3-Eu and LiY〖(SO_4)〗_2-Eu double cation phosphors

Abstract

The mechanisms of creation of intrinsic and impurity trapping centers, the interaction of which forms combined or induced electronic states under the conduction band, have been studied using optical and thermal activation spectroscopy. It is shown that electron-hole trapping centers are created when free electrons are trapped by impurities and ions of the SO4 2- matrix, as well as a result of charge transfer from the excited SO4 2- anion to impurities and to neighboring ions by the reaction (Ο2- - Eu 3+) and (Ο2- - Eu 3+) . The hole component of the trapping center is formed when holes are localized above the valence band. During relaxation, the combined emission state decays with the transfer of energy from its own matrix to the emitters.