Photoluminescence properties of red-emitting Li2ZnSn2O6:Mn4+ phosphor for solid-state lighting

Abstract

Novel Li2ZnSn2O6:Mn4+ (LZSO:Mn4+) phosphor is prepared by the high temperature solid-state reaction method in air. The X-ray powder diffractions of samples with a hexagonal LZSO crystal system are investigated. Excitation spectrum of LZSO:Mn4+ phosphor monitored at 658 nm shows these excitation bands in the range of 220 − 570 nm, which are attributed to the Mn4+ - O2− charge transfer band (220 − 300 nm), the 4A2 → 4T1 transition of Mn4+ ion (300 − 420 nm), and 4A2 → 4T2 transition of Mn4+ ion (420 − 570 nm), respectively. LZSO:Mn4+ phosphor with excitation at 335 and 480 nm emits deep-red light with the strongest emission peak at ~ 658 nm in the range of 600 − 780 nm due to the 2E → 4A2 transition of Mn4+ ion. The optimal Mn4+ concentration is ~ 0.4% in LZSO:Mn4+ phosphor. The lifetime of LZSO:Mn4+ phosphor decreases from 14.32 to 12.05 μs with increasing Mn4+ concentration from 0.2% to 1.0%. The luminous mechanism and energy level splitting of Mn4+ ion in LZSO:Mn4+ phosphor are explained by the Tanabe-Sugano energy level diagram.