Sr3AlO4F:Ce3+-based yellow phosphors: structural tuning of optical properties and use in solid-state white lighting

Abstract

A highly efficient yellow oxyfluoride phosphor Sr_2.97−1.5xCa_xAl_1−2yMg_ySi_yO₄F:0.02Ce³⁺ has been developed as a component of solid state white light emitting diodes (LED). The phosphor emits with a maximum at 545 nm when excited by 430 nm with a quantum efficiency approaching 84%. After substituting magnesium and silicon into the aluminum sites, replacing the strontium by calcium in Sr₃AlO₄F:Ce³⁺, we discovered a class of single phase materials. This results in the emission maximum redshift from 460 nm to 545 nm and the excitation red shift from 400 nm to 430 nm (compared with Sr₃AlO₄F:Ce³⁺). The combination of an InGaN LED chip (λ_max = 430 nm) had a color temperature of about 4500 K and the color rendering index was 78. This phosphor has potential for incorporation into near-UV white LEDs and related applications.