Cyan long lasting phosphorescence in green emitting phosphors Ba2Gd2Si4O13:Eu2+, RE3+ (RE3+ = Dy3+, Ho3+, Tm3+, Nd3+ and Tb3+)

Abstract

Novel long lasting phosphorescence materials Ba₂Gd₂Si₄O₁₃:Eu²⁺, RE³⁺ (RE³⁺ = Dy³⁺, Ho³⁺, Tm³⁺, Nd³⁺ and Tb³⁺) are designed and prepared by a solid state reaction. Their photoluminescence emission spectra show a broad asymmetric green emitting band peaking at 517 nm, attributed to the 5d–4f transitions of Eu²⁺ ion occupying Ba²⁺ and Gd³⁺ site respectively. The Eu²⁺ ion occupying the Gd³⁺ site is not involved in the long lasting phosphorescence process, resulting in an interesting phenomenon that the green emitting phosphors show cyan phosphorescence. The experimental results show that co-doping the rare earth ions can improve the long lasting phosphorescence performance effectively, and with the moderate introduction of Nd³⁺ ion the most persistent cyan emission can last for 3 h approximately. This work shows up an interesting phosphorescence phenomenon, and provides a new and efficient candidate for long lasting phosphorescence materials.