Site-selective and cooperative doping of Gd3Al5O12:Ce garnets for structural stabilization and warm WLED lighting of low CCT and high CRI

Qinghong Meng; Guoying Zhao; Qi Zhu; Xiaodong Li; Xudong Sun; Ji-Guang Li

doi:10.1039/d1dt03599a

Site-selective and cooperative doping of Gd₃Al₅O₁₂:Ce garnets for structural stabilization and warm WLED lighting of low CCT and high CRI

Dalton Trans. 2022 Jan 4;51(2):645-654. doi: 10.1039/d1dt03599a.

Authors

Qinghong Meng¹, Guoying Zhao^{2

3}, Qi Zhu¹, Xiaodong Li¹, Xudong Sun^{1

4}, Ji-Guang Li³

Affiliations

¹ Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education) and School of Materials Science and Engineering, Northeastern University, Shenyang, Liaoning 110819, China.
² School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418, China.
³ Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan. LI.Jiguang@nims.go.jp.
⁴ Foshan Graduate school of Northeastern University, Foshan, Guangdong 528311, China.

PMID: 34908062
DOI: 10.1039/d1dt03599a

Abstract

Synergistic doping of the metastable Gd₃Al₅O₁₂:Ce garnet with a Ca²⁺/Hf⁴⁺ pair and Sc³⁺ to form Gd_2.97-xCa_xHf_xSc_yAl₃O₁₂:0.03Ce (x = 0.5-2.0, y = 0.0-1.5, x + y = 2.0) solid solution was conducted for the structural stabilization and photoluminescence manipulation. The site selection of Ca²⁺/Hf⁴⁺/Sc³⁺ dopants and the effects of doping on the crystal structure, local coordination, band structure and Ce³⁺ luminescence were revealed in detail with the results of XRD, Rietveld refinement, TEM, and UV-Vis/photoluminescence spectroscopy. A decrease in Ca²⁺/Hf⁴⁺ and an increase in the Sc³⁺ content were observed to shrink the lattice, widen the bandgap of the garnet host, red-shift the excitation/emission wavelength, broaden the emission band and shorten the fluorescence lifetime of Ce³⁺. The spectral changes were rationalized by considering the local coordination and crystal field splitting of the Ce³⁺ 5d energy level. Application of typical Gd_0.97Ca₂Hf₂Al₃O₁₂:0.03Ce (x = 2.0, y = 0) cyan and Gd_2.47Ca_0.5Hf_0.5Sc_1.5Al₃O₁₂:0.03Ce (x = 0.5, y = 1.5) greenish-yellow phosphors in w-WLED lighting produced low correlated color temperatures of ∼3842 and 3514 K, high color rendering indices of ∼88 and 93 and favorable luminous efficacies of ∼32.9 and 14.7 lm/W under the excitation of 395 nm n-UV and 450 nm blue LED chips, respectively.