In-air self-reduction synthesis and colour tunable luminescence from SrBPO₅ :Eu²⁺ -Eu³⁺ excited using ultraviolet...

SrBPO₅ :Eu²⁺ -Eu³⁺ phosphors were synthesized using a conventional solid self-reduction reaction in an air atmosphere. Samples were characterized using thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectra, fluorescence spectra and Commission International de l'Eclairage (CIE) data. The results of TGA and DSC showed that the raw materials could completely react at 1000°C. FTIR spectra and XRD results displayed that europium ions of different concentrations do not effect the structure of the hosts. Fluorescence spectra displayed that europium ions exist in bivalent and trivalent forms, and that the emission peak at 403 nm was attributed to the typical 5d-4f transition for Eu²⁺ ; 597 nm and 620 nm emissions were assigned to the characteristic transitions of ⁵ D₀ -7F_{1, 2} for Eu³⁺ . CIE results depicted that the colour tone of the phosphors could be macro-controlled from blue to purple by controlling the doping amount of Eu³⁺ .Therefore, relative luminescence intensity between Eu²⁺ and Eu³⁺ could be adjusted by controlling the doping concentration of europium to tune the luminescence colour of SrBPO₅ .