Development of red phosphor $\mathrm{Li}_{8} \mathrm{CaLa}_{2} \mathrm{Ta}_{2} \mathrm{O}_{13}$ : $\mathrm{Eu}^{3+}$ for WLEDs and anti-counterfeiting applications

Abstract

A set of novel red phosphors Li₈CaLa₂Ta₂O₁₃:xEu³⁺ (LCLTO:xEu³⁺) were successfully prepared using a solid-state reaction method. The properties of the prepared samples, including phase purity, elemental composition, and morphology, were systematically investigated using X-ray diffraction, scanning electron microscopy, and diffuse reflectance spectroscopy analyses. The 610 nm maximum emission peak is attributed to the ⁵D₀→⁷F₂ transition of Eu³⁺ ion under 394 nm irradiation. Among all the LCLTO:xEu³⁺ phosphors, LCLTO:0.6Eu³⁺ showed the strongest emission intensity because of the concentration quenching effect of the electric dipole-dipole interaction among the Eu³⁺ ions, which was also demonstrated by the decay curves. Remarkably, the emission intensity of the optimal LCLTO:0.6Eu³⁺ phosphor, which exhibited a high internal quantum efficiency of 49.30% and excellent color purity of 96.79%, was approximately 2.29 times higher than that of commercial Y₂O₃:Eu³⁺ red phosphors. The thermal stability of the LCLTO:0.6Eu³⁺ sample with good color stability was meticulously investigated. The fabricated white-light-emitting diode (WLED) exhibited a superior color-rendering index of R_a = 82 and chromaticity coordinates of (0.3260, 0.3639), suggesting that LCLTO:0.6Eu³⁺ has potential applicability in developing efficient and high-quality WLEDs. Moreover, the prepared LCLTO:0.6Eu³⁺/PDMS composite film demonstrated exceptional flexural resistance and chemical stability, indicating considerable promise for practical anti-counterfeiting applications.

Keywords

Phosphor / Tantalate / Luminescence / LED device

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

CRediT authorship contribution statement

Jingjing Ru: Writing - original draft, Writing - review & editing, Formal analysis, Data curation, Investigation, Methodology. Fan Zeng: Data curation, Investigation. Bing Zhao: Software, Visualization. Chenqing Ye: Conceptualization, Validation. Tonghui Zhong: Data curation, Investigation. Feiyun Guo: Methodology, Visualization, Formal analysis. Jianzhong Chen: Methodology, Writing - review & editing.

Acknowledgements

This work was supported by the Foundation of Fujian Province (No. 2021J011149), the financial support of Innovative Research Team of Ningde Normal University (No. 2023T03), and Fujian Provincial Department of Education (No. JAT210469).

Supplementary materials

Supplementary material associated with this article can be found, in the online version, at doi:10.1016/j.chphma.2023.11.002.

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