Influence of local structure on photoluminescence properties of Eu³⁺ doped CeO₂ red phosphors through induced oxygen vacancies by contrasting rare earth substitutions

Abstract

A new family of red phosphors, CeREO:0.1Eu (RE = Y and La; x = 0, 0.20, 0.40, 0.60, 0.80, and 0.90), was synthesized by a conventional solid-state route. The influence of contrasting rare earth substitutions (Y and La) in the system was investigated on the local structure and associated photoluminescence properties by various characterization techniques. Both trivalent ion substitutions lead to the same kind of variation during phase transformation from fluorite to the respective parent oxide structure (x ≥ 0.6). On the other hand, the substitutions have a distinct effect on local structure, absorption, luminescence and lifetimes. The smaller Y ion substitution enables the ordering of oxygen vacancies in a lattice, inhibiting the defect formation of Ce oxidation states. In contrast, the larger La ion substitution liberates oxygen vacancies, allowing defect formation. Consequently, the concentration of Ce is dependent on the ionic radius of the metal ions and it has a bearing on the band gap and luminescence properties of the system. CeYO:0.1Eu phosphor exhibited maximum red emission intensity at 612 nm, which is 8 times higher than that of CeO:0.1Eu and better than that of commercial Philips red phosphor, whereas La substitution yielded poor emission intensities with higher concentrations. The co-substitution of contrasting rare earth metals with Eu allow the understanding of local structure and a smaller ion like Y greatly functionalizes CeO:Eu phosphor.

Magnetic Properties of Rare Earth Doped SnO2, TiO2 and CeO2 Nanoparticles

“…Nakayama et al and Raj et al have showed the important role of the oxygen vacancies by the forming of the magnetization. We agree with this statement.…”

“…Oxygen vacancies are the dominant defect species obtained by RE doping. They form associates with the RE ions, and the corresponding defect association energy is a strong function of the ionic radii of the RE dopants . In other words, Y 3+ dopant traps oxygen vacancies at the nearest‐neighbour site strongly, while La 3+ dopant repels oxygen vacancies at the nearest neighbor site.…”

The influence of chemical prehistory on the structure, photoluminescent properties, surface and biological characteristics of Zr0.98Eu0.02O1.99 nanophosphors

“…The following reagents were used in the hydro and solvothermal synthesis of luminescent nanoparticles studied in this work: zirconium (IV) oxychloride octahydrate (98. 5…”

“…It is known that Ln 3+ -doped wide-bandgap semiconductor oxides can exhibit unique optical properties such as single or multicolor radiation, large Stokes shift, narrow spectral transition bands, long lifetime, and high photoluminescence quantum yield [2,3]. The optical properties of oxide nanoparticles doped with Ln 3+ largely depend on the type and structure of the host matrix [4,5]. Therefore, the correct selection of the absorption oscillator is significant for achieving the desired photoluminescence characteristics of lanthanide ions.…”

Estudo da influência dos íons terras raras Er3+, Eu3+ e Pr3+ nas propriedades fotoluminescentes e eletroquímicas do CeO2

“…O íon Eu 3+ é hipersensível ao ambiente químico no qual está inserido e, por esta razão, é utilizado como uma sonda espectroscópica, de forma que o perfil do espectro de emissão fotoluminescente observado fornece informações específicas sobre a estrutura da matriz hospedeira de acordo com a simetria dos sítios que o íon ocupa (CARNALL et al, 1989;KAUR et al, 2015;RAJ et al, 2017). Geralmente, as transições mais importantes para a determinação do sítio de ocupação dos íons Eu 3+ em uma estrutura cristalina são as transições 5 D0-7 F2 e 5 D0-7 F1, de maior intensidade.…”