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Wang L, Zhang Y, Gao D, Sha X, Chen X, Zhang Y, Zhang J, Zhang X, Cao Y, Wang Y, Li X, Xu S, Yu H, Chen B. Luminescence properties and Judd-Ofelt analysis of Tb 3+ doped Sr 2YTaO 6 double perovskite phosphors for white LED applications. Dalton Trans 2024; 53:6399-6409. [PMID: 38498319 DOI: 10.1039/d4dt00302k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
A series of Tb3+-doped Sr2YTaO6 double perovskite phosphors (SYT:Tb3+) were synthesized using a conventional solid-state reaction method. A strong green emission was observed in the SYT:Tb3+ phosphors, and the optimal doping concentration of Tb3+ was confirmed to be 5 mol%. The electric dipole-dipole interaction was ascribed to be the main mechanism for the luminescence concentration quenching. Analysis of the concentration-dependent fluorescence decay confirmed that the self-generated quenching model holds for the dynamic process of Tb3+ decays in SYT. Furthermore, the internal quantum efficiencies, non-radiative transition rates, and energy transfer rates of the 5D4 level for the SYT:Tb3+ samples were estimated, respectively. The luminescence thermal stability of the sample was also evaluated based on the Arrhenius model. The chromaticity shift of the SYT:5 mol% Tb3+ phosphor was examined to be 0.013 when the sample temperature was increased from 303 to 483 K, thus indicating excellent chromaticity shifting resistance under high temperature conditions. Moreover, the Judd-Ofelt parameters were calculated from the emission spectra of SYT:Tb3+ to be Ω2 = 0.29 × 10-20, Ω4 = 0.45 × 10-20, and Ω6 = 0.72 × 10-20 cm2, respectively. The fluorescence branching ratios and radiative transition rates for the 5D4 level were calculated based on the obtained Judd-Ofelt parameters. Finally, a white light-emitting diode (LED) prototype was assembled using a 310 nm LED chip combined with a prepared green SYT:Tb3+ phosphor and two other commercial blue and red phosphors. The obtained warm white light exhibits good chromaticity coordinates (0.32, 0.32) and a high color rendering index of 96.1. Based on the above results, it can be known that the prepared SYT:Tb3+ phosphors have a potential application as green emitting phosphors in white LEDs.
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Affiliation(s)
- Li Wang
- School of Science, Dalian Maritime University, Dalian, 116026, Liaoning, PR China.
- College of Medical Laboratory, Dalian Medical University, Dalian, 116044, Liaoning, PR China
| | - Yuhang Zhang
- School of Science, Dalian Maritime University, Dalian, 116026, Liaoning, PR China.
| | - Duan Gao
- School of Science, Dalian Maritime University, Dalian, 116026, Liaoning, PR China.
| | - Xuezhu Sha
- School of Science, Dalian Maritime University, Dalian, 116026, Liaoning, PR China.
| | - Xin Chen
- School of Science, Dalian Maritime University, Dalian, 116026, Liaoning, PR China.
| | - Yanqiu Zhang
- School of Science, Dalian Maritime University, Dalian, 116026, Liaoning, PR China.
| | - Jinsu Zhang
- School of Science, Dalian Maritime University, Dalian, 116026, Liaoning, PR China.
| | - Xizhen Zhang
- School of Science, Dalian Maritime University, Dalian, 116026, Liaoning, PR China.
| | - Yongze Cao
- School of Science, Dalian Maritime University, Dalian, 116026, Liaoning, PR China.
| | - Yichao Wang
- School of Science, Dalian Maritime University, Dalian, 116026, Liaoning, PR China.
| | - Xiangping Li
- School of Science, Dalian Maritime University, Dalian, 116026, Liaoning, PR China.
| | - Sai Xu
- School of Science, Dalian Maritime University, Dalian, 116026, Liaoning, PR China.
| | - Hongquan Yu
- School of Science, Dalian Maritime University, Dalian, 116026, Liaoning, PR China.
| | - Baojiu Chen
- School of Science, Dalian Maritime University, Dalian, 116026, Liaoning, PR China.
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Wang J, Zakrzewski JJ, Zychowicz M, Xin Y, Tokoro H, Chorazy S, Ohkoshi SI. Desolvation-Induced Highly Symmetrical Terbium(III) Single-Molecule Magnet Exhibiting Luminescent Self-Monitoring of Temperature. Angew Chem Int Ed Engl 2023; 62:e202306372. [PMID: 37335298 DOI: 10.1002/anie.202306372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/07/2023] [Accepted: 06/19/2023] [Indexed: 06/21/2023]
Abstract
A conjunction of Single-Molecule Magnet (SMM) behavior and luminescence thermometry is an emerging research line aiming at contactless read-out of temperature in future SMM-based devices. The shared working range between slow magnetic relaxation and the thermometric response is typically narrow or absent. We report TbIII -based emissive SMMs formed in a cyanido-bridged framework whose properties are governed by the reversible structural transformation from [TbIII (H2 O)2 ][CoIII (CN)6 ] ⋅ 2.7H2 O (1) to its dehydrated phase, TbIII [CoIII (CN)6 ] (2). The 8-coordinated complexes in 1 show the moderate SMM effect but it is enhanced for trigonal-prismatic TbIII complexes in 2, showing the SMM features up to 42 K. They are governed by the combination of QTM, Raman, and Orbach relaxation with the energy barrier of 594(18) cm-1 (854(26) K), one of the highest among the TbIII -based molecular nanomagnets. Both systems exhibit emission related to the f-f electronic transitions, with the temperature variations resulting in the optical thermometry below 100 K. The dehydration leads to a wide temperature overlap between the SMM behavior and thermometry, from 6 K to 42 K. These functionalities are further enriched after the magnetic dilution. The role of post-synthetic formation of high-symmetry TbIII complexes in achieving the SMM effect and hot-bands-based optical thermometry is discussed.
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Affiliation(s)
- Junhao Wang
- Department of Materials Science, Faculty of Pure and Applied Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8573, Japan
| | - Jakub J Zakrzewski
- Faculty of Chemistry, Jagiellonian University Gronostajowa 2, 30-387, Krakow, Poland
| | - Mikolaj Zychowicz
- Faculty of Chemistry, Jagiellonian University Gronostajowa 2, 30-387, Krakow, Poland
| | - Yue Xin
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Hiroko Tokoro
- Department of Materials Science, Faculty of Pure and Applied Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8573, Japan
| | - Szymon Chorazy
- Faculty of Chemistry, Jagiellonian University Gronostajowa 2, 30-387, Krakow, Poland
| | - Shin-Ichi Ohkoshi
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
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