Excellent thermal stability and high quantum efficiency orange-red-emitting AlPO4:Eu3+ phosphors for WLED application

• Published in: Journal of alloys and compounds Vol. 853; p. 156941
• Main Authors: Tran, M.T., Tu, Nguyen, Quang, N.V., Nguyen, D.H, Thu, L.T.H., Trung, D.Q., Huy, P.T.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 05-02-2021; Elsevier BV
• Subjects: AlPO4:Eu3; Aluminum phosphate; Chromaticity; Color; Dopants; Europium; Judd-Ofelt intensity parameters; Orange-red-emitting phosphors; Phosphors; Quantum efficiency; Room temperature; Stability analysis; Symmetry; Thermal stability; Warm white LED; Orange-red-emitting phosphors; Warm white LED; Judd-Ofelt intensity parameters; AlPO4:Eu3
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.156941

Orange-red-emitting AlPO4:Eu3+ phosphors have been systematically synthesized by a co-precipitation method. Under the excitation at 394 nm these phosphor shows strong orange-red emissions with the strongest peaks at 588, 594, 685 and 700 nm. The highest PL intensity is achieved at the dopant concentration of 3 mol% and the annealing temperature of 1000 °C. Additionally, 84% of the room-temperature emission intensity is still maintained at 160 °C, indicating a good thermal stability and practicality. By a Judd-Ofelt (JO) analysis, it is demonstrated that the symmetry sites surrounding Eu3+ ions are influenced by the dopant level. The lowest value of Ω2/Ω4 ratio of 0.27 reveals the highest symmetry site at the Eu3+ concentration of 3 mol%. The CIE 1931 color chromaticity coordinates (x, y) and the activation energy of the AlPO4:3%Eu3+ phosphor are (0.5602; 0.3862) and 0.28 eV, respectively. The color coordinates of the phosphor coated on NUV LED chip and its quantum efficiency (QE) are (0.5573, 0.3253) and 38.7%, respectively. To the best of our knowledge, this is the first time that a calculated QE of AlPO4:Eu3+-based orange-red-emitting LED is reported. The obtained results show a great potential of using orange-red-emitting AlPO4:Eu3+ phosphor for WLED application.
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•Orange-red-emitting AlPO4:Eu3+ phosphor is synthesized by a co-precipitation method.•The highest PL intensity is obtained at the annealing temperature of 1000 °C and the Eu3+ ions concentration of 3 mol%.•The highest symmetry site is found at the Eu3+ concentration of 3 mol% by a modified Judd-Ofelt analysis.•The color coordinates and quantum efficiency of phosphor-coated LED chip are (0.5573; 0.3253) and 38.7%, respectively.