Influence of Si⁴⁺ substitution on the temperature-dependent characteristics of Y₃Al₅O₁₂:Ce

A series of Y₃Al₅O₁₂:Ce (YAG:Ce) phosphors doped with different Si⁴⁺ concentrations is prepared by solid-state reaction. The temperature dependent characteristics of luminescent spectrum and decay time of Ce³⁺ are investigated. With Si⁴⁺ doped, the emission spectrum shows a blue shift due to a decrease of the splitting of 5d levels of Ce³⁺ ion. The thermal stability is greatly improved by adding Si⁴⁺ because the activation energy ΔE increases from 0.1836 eV to 0.2401 eV. The study of the decay times against temperature for various doping concentrations of Si⁴⁺ shows that the calculated nonradiative decay rate is affected by Si⁴⁺ substitution. The results are explained by the configurational coordinate diagram.