Robust white light emission of UV pumped SrCeO3: xSm3+ perovskites for wLEDs

Abstract

Abstract Single phased white light emitting phosphors are more ideal for fabricating white LEDs due to higher stability and color reproducibility. Herein, we report a new white light emitting phosphor, SrCeO3: xSm3+ (x = 1 wt%, 2 wt%, 3 wt%) from a blue light emitting phosphor, SrCeO3 using an efficient, low energy consuming fuel excess gel combustion technique. From the XRD crystallographic investigation, all the synthesised samples have orthorhombic structure with space group Pnma. A broad absorption band in the UV–visible spectra around 350 nm occurs due to the efficient energy transfer from Ce4+ to Sm3+ ion. PL spectra analysis at UV excitations 280 nm and 406 nm, consist of 4f-Sm3+ transitions 4G5/2-6H5/2, 4G5/2-6H7/2, 4G5/2-6H9/2 and charge transfer band from O2− to Ce4+. The energy transfer between activator ions occurs through dipole–dipole interaction, owing to concentration quenching after 2 wt% Sm3+ and the optimised dopant concentration was 2 wt%. SrCe0.98Sm0.02O3 showed mixed blue-yellow-orange-red emission, owing near white light under both excitations. PL data were utilised to find the color parameters and found high color rendering index (CRI ∼ 84) for optimised sample at 406 nm excitation. SEM analysis reveals that the optimised sample exhibit dense ensembled morphology with well-defined grain boundaries and uniformity with average grain size ∼1.24 μm. Further, the elemental composition was confirmed using EDS analysis. From the digital photographs of samples, it is foreseen that, SrCe0.98Sm0.02O3 pumped using near UV LED chip can be used for commercial white light generation.