Synthesis and luminescence properties of Eu2+-doped calcium silicon nitride by the carbothermal reduction and nitridation of spray-pyrolyzed powder

Abstract

Eu2+-doped calcium silicon nitride (Ca2Si5N8: Eu2+) was synthesized by the carbothermal reduction and nitridation of oxide powder prepared by ultrasonic spray pyrolysis. The starting materials, i.e., CaCO3, Si3N4 and Eu2O3 (stoichiometric composition for Ca2Si5N8: 1 mol% Eu2+), were mixed with various amounts of C and then heated at a temperature between 1450 and 1650 deg C in N2 atmosphere. The Eu2+-doped Ca2Si5N8 was obtained by heating the mixture at 1550 deg C for 2 h; the amount of carbon was 1.5 times as large as the stoichiometric amount. Similarly, Eu2+-doped Ca2Si5N8 could be synthesized from the mixture of C and oxide powder prepared by ultrasonic spray pyrolysis. The resulting powder emitted the orange light when the blue-UV light was irradiated to it.