Luminescence properties of Ca3Ti2O7:Eu3+, Bi3+, R+ (R+ =Li+, Na+, and K+) red emission phosphor

摘要

A series of Ca3Ti2O7:Eu3+, Ca3Ti2O7:Eu3+, Bi3+, Ca3Ti2O7:Eu3+, R+, and Ca3Ti2O7:Eu3+, Bi3+, R+ (R+ =Li+, Na+, and K+) phosphors are synthesized by solid-state reaction method in air. All phosphors show bright red emissions centered at similar to 617 nm upon excitation with UV light of 397 nm. Bi3+ is a sensitizer for the luminescence of Eu3+, and can improve significantly the PL intensity of Ca3Ti2O7:Eu3+ phosphor due to energy transfer between Bi3+ and Eu3+ ions. The sensitization mechanism is investigated and discussed by energy level diagrams of Bi3+ and Eu3+ ions. R+ ion is used as the charge compensator to improve the luminescence intensity of Ca3Ti2O7:Eu3+ and Ca3Ti2O7:Eu3+, Bi3+ phosphors, and their PL intensities are enhanced in the sequence K+ -> Na+ -> Li+. These phosphors can be promising red emitting candidate for white LED with a similar to 397 nm near UV chip excitation owing to the high brightness. (C) 2014 Elsevier Inc. All rights reserved.