Tailoring high purity orange-red emission in Sm3+ activated SrTi(PO4)2 phosphor for lighting and display devices

An anhydrous double monophosphate, SrTi(PO4)2, was utilized as a host for RE-incorporated phosphor material for the first time. A series of orange-red emitting, Sm3+ doped SrTi(PO4)2 are synthesised by employing high-temperature solid-state reaction method. The structural, optical, luminescent and spectroscopic characteristics are extensively studied using XRD, FTIR, FE-SEM, DRS, PL spectroscopy and JO theory. The sample crystallizes in a monoclinic system with space group C2/m, having a loosely packed bubbly structure in the sub-micrometre range. PL emission spectra reveal the highly pure orange-red emission which can be effectively excited by n-UV radiation. The optimum Sm3+ ion concentration is 0.05 mol and the Dexter theory explains the luminous intensity quenching at higher concentrations as the energy transfer via dipole-dipole interaction. The longer radiative lifetime in the 2 ms range and the excellent colour purity make the prepared Sm3+ doped SrTi(PO4)2 an orange-red emitting phosphor for lighting, sensing and display devices.