Synthesis and photoluminescence properties of perovskite LaMg0.667Nb0.333O3:Mn4+,Bi3+: a novel deep-red phosphor for WLEDs

Abstract

Red phosphors have kept booming in white light emitting diodes (WLEDs) during the past few years. Herein, a novel complex perovskite LaMg_0.667Nb_0.333O₃:Mn⁴⁺,Bi³⁺ (LMN:Mn⁴⁺,Bi³⁺) deep-red phosphor was synthesized for the first time via a microwave irradiation method. Effective deep-red light peaking at 709 nm was observed when the phosphors were excited by near-ultraviolet (NUV) light. Based on the optimized concentration of Mn⁴⁺ in LMN, Bi³⁺ was selected as the sensitizer to further enhance the luminescence properties. Furthermore, the high thermal stability of the optimized co-doped phosphor was confirmed by thermal luminescence spectra compared to reported phosphors with similar structures. Finally, LED devices were fabricated based on commercial blue and green phosphors with NUV chips, and the results showed a high color rendering index (CRI, R_a = 85.5). All the performances imply great commercial potential as a deep-red phosphor for WLED applications.