Dual-Mode Luminescence with Broad Near UV and Blue Excitation Band from Sr2CaMoO6:Sm3+Phosphor for White LEDs

Abstract

Dual-mode excitation properties were introduced in Sm3+ doped Sr2CaMoO6 prepared by a high temperature solid state reaction technique. Two ways are available to generate white light in the single-component phosphor activated by Sm3+ ions. Warm white light can be obtained from Sr1.995Sm0.005CaMoO6 phosphor pumped by 380 or 411 nm excitation energy. The full visible spectral emission of the single-phase phosphor comes from the high and low level emission lines of Sm3+ ions as well as the intrinsic luminescence of MoO6 group. It is also competitive as yellow-emitting phosphor for blue pumped white LEDs and gives three emission bands at 567, 603, and 650 nm, presenting yellow luminescence upon 466 nm radiation. The 650 nm red emission band corresponding to 4G5/2 → 6H9/2 transition of Sm3+ can make its color rendering index better. The excellent photoluminescence of Sr2CaMoO6 is related to the partial tilting CaO6 octahedral and the lowered symmetry were confirmed by General Structure Analysis System. Band gap...