Green-emitting Bi3+-doped La2SrSc2O7 phosphor for pc-WLED lighting: Luminescent properties and energy transfer strategy

Abstract

The crystal structure, photoluminescence properties, thermal stability and corresponding mechanisms of the novel Bi 3+ , Eu 3+ -doped La 2 SrSc 2 O 7 (LSS) phosphors have been measured and analyzed in details. The emission spectrum of LSS: 1.0%Bi 3+ phosphor shows a novel green emission centered at 530 nm under 340 nm excitation, which is attributed to the 3 P 1 → 1 S 0 transition of Bi 3+ ions. By designing Bi 3+ →Eu 3+ energy transfer strategy, luminescence colors of LSS: 1.0%Bi 3+ , yEu 3+ (y = 0–5.0%) phosphors can be tuned from green to orange with increasing Eu 3+ concentration, which achieve multiple emission colors in LSS host. The photoluminescence decay curves, average decay lifetimes, energy transfer efficiency and time-resolved emission spectra of LSS: 1.0%Bi 3+ , yEu 3+ (y = 0–5.0%) phosphors prove the existence of energy transfer from Bi 3+ to Eu 3+ . The prototype pc-WLED device with green-emitting LSS: 1.0%Bi 3+ possesses high color rendering index (CRI = 96.0) and low correlated color temperature (CCT = 4306 K). These results provide clear evidences that LSS: Bi 3+ and LSS: 1.0%Bi 3+ , Eu 3+ phosphors would be novel promising green-to-orange tunable phosphor candidates for pc-WLED applications. A novel green-emitting La 2 SrSc 2 O 7 : Bi 3+ phosphor and the energy transfer strategy from Bi 3+ ions to Eu 3+ ions. • A novel La 2 SrSc 2 O 7 : Bi 3+ green phosphor was synthetized by high-temperature solid-state method. • The energy transfer from Bi 3+ ions to Eu 3+ ions was designed to realize color tuning from green to orange . • The pc-WLED fabricated by LSS:Bi 3+ phosphor possesses high color rendering index and low correlated color temperature.