Tuning excitation and emission of Mn4+ emitting center in Y3Al5O12 by cation substitution

Abstract

Recently, Mn4+ doped oxide red phosphors have been attracted great attention for promising application in white light-emitting diode to improve optoelectronic properties. Unfortunately, most of Mn4+ doped oxide phosphors suffer from low absorption/excitation in blue light region and deep red emission. In this work, taking Y3Al5O12 as the Mn4+ doped host, we demonstrate the tunability of excitation and emission of Mn4+ activator via cation substitution. X-ray diffraction patterns confirm that Y3+ and Al3+ in the host can be completely replaced by Gd3+/Lu3+ and Ga3+, respectively. Impressively, the substitution of Al3+ ions by Ga3+ ones is beneficial to significantly enhance Mn4+4A2→4T2 blue excitation band and shift 2E→4A2 red emission band toward low-energy region; the replacement of Y3+ by Gd3+ induces red-shifting of both Mn4+ excitation and emission bands while Lu3+ doping leads to the opposite result. These phenomena may be attributed to the doping-induced alteration of Mn4+ local environments, i.e., the covalency of Mn4+ ligand field. Finally, inorganic Ce3+: Y3Al5O12 and Mn4+: Y3Al5O12 dual-phase embedded glass ceramic is prepared by a low-temperature co-sintering route to replace phosphors in organic silicone as color converter, and by combining the synthesized glass ceramic with InGaN blue chip, warm white light-emitting diode with superior optical performance is successfully realized.