Photoluminescence study in Ce activated M6B5AlO15 (M = Sr,Ca, Ba) and mixed host aluminoborate phosphors

In this paper we report the modified solid state synthesis of Ce³⁺ activated Sr₆B₅AlO₁₅, Ca₆B₅AlO₁₅ Ba₆B₅AlO₁₅ and mixed host aluminoborate phosphors. The prepared phosphors were characterized by photoluminescence technique. The PL excitation spectra showed the excitation peaks ranging from 300 to 400 nm and emission spectra are observed in UV-blue region of spectrum and it varied for different hosts. This kind of emission is due to 4f⁶5d → 4f⁷ transition of Ce³⁺ ion. Further PLE and PL emission spectra for various compositions Ca₅Sr₁B₅AlO₁₅, Ca₄Sr₂B₅AlO₁₅, Ca₃Sr₃B₅AlO₁₅, Ca₂Sr₄B₅AlO₁₅, CaSr₅B₅AlO₁₅ are also taken which shows Ce³⁺ emission at 428 nm, 425 nm, 432 nm, 427 nm, 438 nm respectively. The calculated ²F_J (J = 7/2, 5/2) energy gap of Ce³⁺ in all hosts have been calculated and obtained values for Sr₆B₅AlO₁₅, Ba₆B₅AlO₁₅ phosphors are 1888 cm⁻¹ and 1330 cm⁻¹ respectively. PL emission spectra of mixed host aluminoborates have shown slight variations in positions of emission peaks.