Preparation and Luminescence Properties of CaAlSiN3: Eu2 +

Red-emitting nitridoaluminosilicate phosphor CaAlSiN3: Eu2+ was prepared by high temperature solid-state reaction method using calcium hydride (CaH2) as the reducing agent and calcium source. Influence of synthesis temperature on the crystalline structure, morphology and photoluminescence properties of CaSiAlN3: Eu2+ was examined in detail. It was found that samples synthesized at low (1300∼1470 °C) or high (1650∼1700 °C) temperatures, had relatively poor composition, structural properties and performance, such as wider half peak width and lower photoluminescence intensity. Meantime, the relevance of oxygen content and photoluminescence properties was discussed. After that, dependence of photoluminescence and diffuse reflection spectra on Eu2+ ion concentration was investigated. The series of Ca1–x Eu x AlSiN3 (x = 0.005∼0.12) phosphors showed broad excitation and absorption bands (200∼600 nm) and their peak positions redshifted from 642 to 681 nm with the Eu2+ ion content increasing. Surprisingly, red persistent luminescence was observed in CaAlSiN3: Eu2+ with a longer duration in low Eu2+ concentration regions (x ≤ 0.01).