The effect of oxygen-containing anions on luminescent properties of CsI

Abstract

It has been found that from the series of oxygen-containing impurities CO₃²⁻, SO₄²⁻, HCO₃–, OH–, IO₃–, NO₃–, NO₂–, CNO–, BO₂– only the bivalent ions stimulate an intensive blue luminescence in CsI crystals at UV- or gamma-excitation. The blue luminescence intensity is higher in CsI(CO₃) than in CsI(SO₄) crystals. The nature of blue luminescence components has been considered and two types of centres have been suggested: the impurity type – CO₃²⁻-Va⁺ (395 nm) and the structural one – Va⁺-Vc⁻ (435 nm). A method of deep purification of the melt from oxygen-containing anions during the growth process has been proposed.