Tailored luminescence of Bi doped Ca3Ga4O9 phosphors with the substitution of strontium ions

Bi3+ ion-doped phosphors have a wide range of applications in white light emitting diodes (W-LEDs), temperature sensing, long persistent materials and anti-counterfeiting. In this work, a series of Ca2.97-xSrxGa4O9: 3mol%Bi3+ phosphors were prepared via a high-temperature solid-state reaction process. X-ray diffraction (XRD), photoluminescence and 3D thermoluminescence spectra were collected to characterize the samples. The emission spectra of samples demonstrated that Bi3+ ions occupied two different Ca sites with different coordination. Due to the variations in crystal field splitting and site-selective occupancy of Bi3+, photoluminescence spectra can be adjusted sequentially when strontium ions were introduced. Additionally, a detailed analysis of the variation on the trap intensity and the energy transfer between the traps and the luminescence centers has been carried out by 3D-thermoluminescence with cation substitution.