Deep reddish-orange emitting Sr3Gd(PO4)3: Sm3+ phosphors via modified citrate-gel combustion method

Abstract

The photoluminescence properties of different concentrations of Sm3+ activated Sr3Gd(PO4)3 phosphors synthesized by modified citrate gel-combustion method were investigated for white light emitting diode (w-LED) applications. The studied phosphors were characterized through powder x-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), photoluminescence excitation, emission and lifetime studies. The PXRD profiles confirmed the body centred cubic structure of undoped and Sm3+ -doped phosphors. The SEM studies showed the distribution and agglomeration of particles. The characteristic emission transitions such as 4G5/2 → 6H5/2 (∼561 nm), 4G5/2 → 6H7/2 (∼598 nm), 4G5/2 → 6H9/2 (∼645 nm) and 4G5/2 → 6H11/2 (∼705 nm) were noticed at their respective positions when excited at 403 nm wavelength. The highest luminescence intensity was found for 1.0 mol% of Sm3+ doped phosphors at 403 nm excitation showing luminescence quenching and it was ascribed to dipole-dipole interaction type of energy transfer among the excited Sm3+ ions at higher concentrations. The reddish-orange color of emitted luminescence was examined by evaluating the chromaticity coordinates. The experimental results confirm the potentiality of studied phosphors for w-LED applications.