Novel White Phosphor Bi3+ co-doped SrCeO3: 2 wt% Sm3+ Synthesized via Fuel Excess Gel Combustion Synthesis for wLED Applications.

Abstract

Co-doping strategy is done if the emission from the activator is relatively low with existing excitation energy. Thus, to enrich the emission from an activator, the sensitizer like Bi³⁺ is co-doped onto the host and this intermediator transfers its emission energy to the activator. Prior to the study, no investigations had been conducted, marking the foundational exploration of the sensitizer effect within the rare earth-doped SrCeO₃ matrix aimed at enhancing luminescence properties. The current study focuses on the innovation of single-phase robust white phosphors, SrCeO₃: 2wt% Sm³⁺: xBi³⁺ (x = 0 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%) to coat near UV LED chips for high CRI wLED applications. The novel perovskites were synthesized using a low-temperature fuel excess gel combustion method, utilizing citric acid as the fuel and ammonium nitrate as an extra oxidizer. Upon co-doping SrCeO₃: 2wt% Sm³⁺ with bismuth, the impact of changing sensitizer concentration on both the development of crystalline phases, morphology, elemental composition, band gap energy, and the luminescent properties of ceramic powders were explored through X-ray diffraction, FE-SEM, Energy dispersive spectra, UV-visible absorption spectra, and photoluminescence characterization methods. The experimental results revealed the orthorhombic single-phase formation of SrCeO₃: 2wt% Sm³⁺: xBi³⁺perovskites yielding high crystallinity and luminescence maximum at critical sensitizer concentration 1 wt% Bi³⁺. Also, the bright white light emission of all the perovskites was confirmed using the CIE color diagram. Thus, nano-perovskite SrCe_0.97Sm_0.02O₃: 1wt% Bi³⁺ acts as an inevitable direct phosphor coating the near UV chip in LEDs, which can be a great revolution in energy savings applications.