Photoluminescence Properties of Red-Emitting Mn2+-Activated CaAlSiN3 Phosphor for White-LEDs

摘要

Mn2+-doped CaAlSiN3 phosphors have been prepared by a solid-state reaction method at high temperature and the solubility of Mn2+ in the host lattice as well as their photoluminescence properties were investigated. In CaAlSiN3, not only Ca2+ sites, but also Al3+ sites can be substituted by Mn2+ ions. CaAlSiN3 : Mn2+ absorbs blue light in the spectral range of 440–460 nm, and exhibits a broad band emission in the wavelength range of 475–750 nm, which can be ascribed to the 4T1 (4G) ? 6A1 (6S) transition of Mn2+ located at two different sites in CaAlSiN3. The emission bands at lower energy (15,950 cm?1 or 627 nm) and higher energy (18,250 cm?1 or 548 nm) are assigned to the Mn2+ locating at the Al site (MnAl) and Ca site (MnCa), respectively with energy transfer from MnCa to MnAl. In addition, the integral luminescence intensity only decreases to about 94% at 150?C of the value at 50?C, which is of great interest for the applications of white-LEDs.