JOURNAL OF ALLOYS AND COMPOUNDS
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2020
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IF 4.65
Jiangwei Du,Xiaoyan Pan,Zepeng Liu,Yetao Jing,Beicheng Wang,Laihui Luo,Jun Wang,Peng Du
To fulfill bifunctional applications of the white light-emitting diode (white-LED) and optical thermometry, Eu 3+ -activated Ca 2 Gd 8 Si 6 O 26 phosphors were prepared. Upon 394 nm excitation, dazzling red emission with admirable color purity of 93.8% was seen and the optimal doping content of the Eu 3+ ions in the Ca 2 Gd 8 Si 6 O 26 host was 30 mol%. The Ca 2 Gd 8 Si 6 O 26 :2.4Eu 3+ phosphors showed a high quantum efficiency of 53.9%. Via investigation of the relation between the dopant content and emission intensity, one knows that the concentration quenching mechanism was decided by electric dipole-dipole interaction. Though estimating the values of Ω 2 and Ω 4 based on the Judd-Ofelt theory, it was proved that the Eu 3+ ions took the low symmetry sites in the Ca 2 Gd 8 Si 6 O 26 host lattices. Furthermore, the temperature-dependent emission spectra manifested that the resultant compounds had splendid thermal stability with activation energy of 0.25 eV. Utilizing the prepared compounds as the red-emitting components, a white-LED was packaged and it can emit high quality white light with high color rendering index (84.8) and low correlated color temperature (4981 K). Additionally, through analyzing the temperature-dependent excitation spectrum, the optical thermometric behaviors of the designed phosphors were studied. The maximum absolute and relative sensitivities of the studied compounds were 0.0014 K -1 and 0.276% K −1 , respectively. These results provided a new insight into searching for novel bifunctional luminescent materials towards white-LED and ratiometric optical thermometer applications.
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
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2023
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IF 5.2
Nan Yang,Zhuo Li,Ziwang Zhang,Wen He,Zhibin Ye,Weijie Huang,Jianxin Shi,Yexiang Tong
Recently, more and more attention has been concentrated on luminescence materials activated with rare-earth ions for white light-emitting diodes (WLEDs) or optical thermometers. However, due to their opposite requirements for thermal response, it is hard to realize the above dual applications in the same material. Herein, a red-emitting tantalate phosphor, Gd 3 TaO 7 :Eu 3+ , was designed and prepared to solve the problem. The emission of Eu 3+ in the phosphor was surprisingly observed to be different from that in most of the reported red phosphors activated with Eu 3+ , that is, the emissions coming from the f - f transitions of Eu 3+ exhibit severe splitting, and the intensities of several strong transitions are not very different. According to the structural and spectral analyses, the reasons may be the highly covalent and polarized lattice environments of Eu 3+ in this material. When excited with 393 nm, the temperature-dependent photoluminescence (TDPL) of Gd 3 TaO 7 :Eu 3+ presents a normal thermal quenching and the integrated intensity at 500 K keeps 90.8 % compared to that at 300 K. Whereas the TDPL presents an edge abnormal thermal quenching phenomenon upon the excitation of 330 nm. Taking advantage of the special TDPL characteristics, a WLED device and a multiple-mode optical thermometer are successfully realized in this material. The former has excellent performances with high Ra of 88.8 and low CCT of 3882 K, and the latter includes one type of excitation intensity ratio and two types of fluorescence intensity ratio with the maximal relative temperature sensitivities of 0.92 % K −1 , 0.97 % K −1 and 0.92 % K −1 , respectively. The results reveal that Gd 3 TaO 7 :Eu 3+ phosphor has a great prospect in WLED and multiple-mode optical temperature sensor dual-applications, and this work may provide a new and effective strategy for developing multifunctional optical materials.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RARE EARTHS
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2023
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IF 4.9
Wei Zhang,Changjian Wang,Xusheng Qiao,Xianping Fan
The rapid development of phosphor-converted white light emitting diodes (pc-WLEDs) requires new red phosphors with efficient and thermally stable luminescence for high-quality warm-white lighting. However, it is still a challenge to discover red phosphors with facile synthesis, high internal quantum efficiency (IQE), excellent thermal stability and high color purity. Herein, a novel red-emitting Eu 3+ activated barium dialuminum digermanate (BaAl 2 Ge 2 O 8 , BAGO) phosphor showing strong red emission at 610 nm was prepared. The IQE is improved from 32.91% to 78.84% by employing a charge compensation strategy. The lithium-ion co-doped BAGO:Eu 3+ phosphor exhibits a nearly twofold increase in integral photoluminescence (PL) intensity and the high color purity reaches 94.17%. Impressively, the PL intensity of the BAGO:Eu 3+ ,Li + phosphor drops by only 2.6% at 150 °C of that at room temperature. Finally, the pc-WLED using the red BAGO:Eu 3+ ,Li + phosphor exhibits white light with the chromaticity coordinate of (0.3515, 0.3495), a high color-rendering index of 92 and a low correlated color temperature of 4746 K. All these results manifest that BAGO:Eu 3+ ,Li + phosphor is a suitable red phosphor for near-ultraviolet (NUV) chip-based pc-WLEDs.
研究领域:
材料科学
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光电
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发光二极管
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
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2024
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IF 2.7
Feiyan Xie,Junqiang Gu,Dekang Xu,Qiancheng Xiong,Jinyu Yang,Xiangjian Ou,Dawei Wen
Research into red phosphors with a high color rendering index is particularly compelling, given the absence of a red component in the spectrum of commercial pc-WLEDs, which combine blue LED chips with yellow-emitting YAG:Ce3+ phosphors. Herein, we reported a novel Eu3+ activated Ca3Zn3Te2O12 red-emitting phosphor, synthesized using a conventional high-temperature solid-phase method. The phase and crystal structures were analyzed by powder X-ray diffraction and Rietveld refinement. The optimal excitation peak of the Ca3Zn3Te2O12:Eu3+ phosphor was located at 395 nm, matching those of conventional commercial near-ultraviolet chips. In addition, the Ca3Zn3Te2O12:9%Eu3+ phosphor exhibited good thermal stability, with an activation energy of 0.267 eV, and the CIE color coordinates hardly changed with temperature. Ultimatel, a high-quality white LED device was fabricated by combining Ca3Zn3Te2O12:9%Eu3+ red phosphor, a commercial BaMgAl10O17:Eu2+ blue phosphor, and(Ba,Sr)2SiO4:Eu2+ green phosphor with a 395 nm near-UV chip. Despite a substantial increase in the input current from 20 to 320 mA, the white-LED maintained a stable color rendering index of around 80, highlighting its consistent performance. These results indicated that Eu3+ activated Ca3Zn3Te2O12 phosphors are promising red emission candidates for white LEDs pumped by near ultraviolet chips.
研究领域:
材料科学
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光电技术
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光子学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）