Photoluminescence and energy transfer studies on Eu 2+ and Ce 3+ co-doped SrCaSiO 4 for white light-emitting-diodes

Abstract

The luminescence of SrCaSiO 4:Eu 2+, Ce 3+ is studied as a potential ultraviolet light-emitting diodes (UV-LEDs) phosphor that is capable of converting the ultraviolet emission of a UV-LED into green light with good luminosity. There are two emissions peaks peaking at 420 and 500 nm, respectively. The two emissions come from d–f transitions of Ce 3+ and Eu 2+, respectively. Effective energy transfer occurs in Ce 3+/Eu 2+ co-doped SrCaSiO 4 due to a part of spectral overlap between the emission of Ce 3+ and excitation of Eu 2+. Co-doping of Ce 3+ enhances the emission intensity of Eu 2+ greatly by transferring its excitation energy to Eu 2+. The Ce 3+/Eu 2+ energy transfer, thoroughly investigated by the diffuse reflection emission and excitation spectra, photoluminescence decay curves, is demonstrated to be in the mechanism of electric dipole–dipole interaction.