Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 6
·2153-2161
·
IF 6.4
Tao Hu,Zelong Jiang,Bo Wang,Ting Yu,Dawei Wen,Qinguang Zeng,Yan Gao
Fine control of the photon emission of Eu2+ activated luminescent materials is essential for advanced optoelectronic applications. However, it remains difficult to design blue light excitable Eu2+ doped oxide red phosphors due to the ionicity of the oxide ions. Herein, we have mechanistically demonstrated that an Eu2+ incorporated CaYGaO4 phosphor exhibits efficient red emission at 650 nm, as a result of the Eu2+ 4f65d1 electronic state experiencing strong crystal field splitting. DFT calculations reveal that the Eu2+ ion is energetically favored in the octahedral Ca2+ site, which is responsible for the fascinating optical properties. We have also demonstrated a strategy of post thermal annealing for improving both the emission efficiency and thermal emission quenching properties of this newly developed red phosphor. By employing the as-fabricated phosphor as a red color convertor, a warm white lighting device with a high color render index of 89.7 and low corrected color temperature of 3780 K was constructed. Our findings not only provide a promising red phosphor candidate for lighting of excellent quality, but also help to stimulate new routes for designing and improving the photon emission of rare-earth luminescent materials.
研究领域:
材料科学
·
光电技术
·
发光材料
·
照明技术
✓ 已验证
产品关联
DOI
高影响因子
Laser & Photonics Reviews
·
2025
·
IF 10
Zhiyu Yang,Guangxiang Lu,Jiani Ma,Tao Yang,Guotao Xiang,Li Li,Xianju Zhou,Zhiguo Xia
The rapid advancements in solid-state lighting have underscored the need for efficient and thermally stable phosphors for light-emitting diode (LED) applications. Herein, a red phosphor CaSc 2 O 4 :Eu 2+ ( λ ex = 450 nm, λ em = 650 nm) is synthesized employing a non-stoichiometric strategy to increase photoluminescence quantum efficiency (PLQY). Spectroscopic and crystallographic properties analysis confirm that the red emission band originates from Eu 2+ ions occupying a single Ca 2+ site with significant nephelauxetic effects and crystal field splitting. Excessive CaCO 3 additions promote the reduction of Eu 3+ and an increase of trap concentration, enhancing the PLQY from 24% to 61% and improving the emission intensities at 150 °C from 8% to 41% of that at room temperature. Versatile LED light sources, including high-quality white LED, red LED in plant growth, and the integrated pixelated intelligent LED matrices have been explored for the practical applications. This study proposes an optimized strategy to enhance the efficiency and thermal stability of Eu 2+ -doped oxide-based red phosphors for multifunctional lighting applications.
研究领域:
材料科学
·
固体照明
·
发光材料
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2018
·
IF 2.873
Hao Zhong,Jun-Wei Wang,Bin-Bin Dong,Lin Li,Ming-Ye Yang,Jun-Ling Yu,Xu Xin,Simeon Agathopoulos
The red-emitting Sr[LiAl 3 N 4 ]:Eu 2+ (SLA) phosphor was synthesized under flowing N 2 gas. A thin organosilica layer (about 5–10 nm) was coated on the surface of SLA phosphors by a very simple method, which transformed the phosphor surface from hydrophilicity to hydrophobicity . The contact angle of water droplets on the surface of the packed SLA phosphors was more than 140°. Compared with the unmodified sample, the modified SLA phosphors could keep at a high emission intensity for more than twice the time under an extremely high moisture level (at relative humidity of 100%, 85 °C). The hydrophobic modification could also improve the uniform dispersion of phosphors during assembly process of white LED .
研究领域:
材料科学
·
化学
·
光电
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2023
·
IF 4.6
Baofeng Zheng,Yanhua Song,Zhibo Zheng,Yanxia Zhao,Qing Yang,Zhan Shi,Bo Zou,Haifeng Zou
A novel green-light-emitting silicon-based oxynitride phosphor Ca4Y3Si7O15N5:Eu2+ with low thermal quenching and ideal pressure sensitivity is reported. The Ca3.99Y3Si7O15N5:0.01Eu2+ phosphor can be efficiently excited by 345 nm ultraviolet light and shows very low thermal quenching (integrated and peak emission intensities at 373 and 423 K were 96.17, 95.86, and 92.73, 90.66% of those at 298 K, respectively). The correlation between high thermal stability and structural rigidity is investigated in detail. The white-light-emitting diode (W-LED) is assembled by depositing the obtained green-light-emitting phosphor Ca3.99Y3Si7O15N5:0.01Eu2+ and commercial phosphors on a ultraviolet (UV)-emitting chip (λ = 365 nm). The CIE color coordinates, color rendering index (Ra), and corrected color temperature (CCT) of the obtained W-LED are (0.3724, 0.4156), 92.9, and 4806 K, respectively. In addition, when subjected to in situ high-pressure fluorescence spectroscopy, the phosphor exhibits an evident red shift of 40 nm with an increase in pressure from 0.2 to 32.1 GPa. The phosphor has the advantage of high-pressure sensitivity (dλ/dP = 1.13 nm GPa–1) and visualization with pressure changes. The possible reasons and mechanisms are deeply discussed in detail. Based on the above advantages, Ca3.99Y3Si7O15N5:0.01Eu2+ phosphor is expected to have potential applications in W-LEDs and optical pressure sensing.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
Materials Today Advances
·
2024
·
IF 8.1
Reziwanguli Yantake,Aierken Sidike,Wang Qingling,Zhou Shihang
Among the green-cyan phosphors widely used in white LEDs, the full width at half maximum, thermal stability and quantum efficiency are key performance indicators. This kind of phosphor should have stable peak shape and peak position when working at different temperatures. It should simultaneously exhibit ultrawideband emission, which is conducive to the realization of two-color white light and simplification of the preparation process of white LED devices. In this paper, a series of KAlSiO 4 :Eu 2+ , Mn 2+ luminescent materials were synthesized by a high-temperature recalcination strategy. Phase analysis and refinement results showed that the samples were effectively synthesized. After the first calcination, a bright green powder was obtained. The main emission peak was at 514 nm, and the FWHM was 30 nm. After recalcination, the color of the light emission from the representative samples changed from green to cyan-green, which was very close to white light, under near-UV irradiation. The emission range was wide, including blue and green light, and the full width at half maximum could reach 150 nm. After recalcination, the emission intensity of the representative samples increased by 3.4 times, and the quantum efficiency reached 90 % under near-UV excitation. The emission intensity at 150 °C was 82 % of that at room temperature. The Raman spectra showed that recalcination had a good effect on the lattice symmetry of the samples and promoted their luminescence intensity. The experimental value of the optical bandgap of the matrix was 5.6 eV, whereas the DFT-calculated bandgap was 4.8 eV, indicating good thermal stability. The chromaticity shift of the sample at high temperatures was very small, indicating good chromaticity stability. A commercial broadband red powder and representative samples after refiring were combined with 365 nm near-UV chips. The color rendering index of the white LED devices exhibited under different driving currents was greater than 90, indicating that the refiring strategy successfully improved the luminous performance of the representative samples. KAlSiO 4 :Eu 2+ , Mn 2+ phosphors were verified to have good application prospects in the field of white LED lighting. This work provides a new idea and technology for calcination and color control of luminescent phosphors.
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 Materials Chemistry C
·
2024
·
IF 5.7
Zhibin Ye,Ziwang Zhang,Nan Yang,Zhuo Li,Weijie Huang,Jianxin Shi
Artificial light sources have a significant impact on the cultivation of houseplants. In this work, a novel single-phase dual-emission phosphor, Ca18Na3Y(PO4)14:Eu2+,Mn2+ (CNYPO:Eu2+,Mn2+), was synthesized and the emission spectra were modulated by co-doping of Mg2+ to better match the absorption of plants. The occupancies of Eu2+, Mn2+ and Mg2+ are analyzed by using the data of bond length from XRD Rietveld refinements and the emission spectra. The energy transfer process from Eu2+ to Mn2+ is proved through the photoluminescence spectra and decay curves. Benefiting from the efficient energy transfer, two broadband emissions peaking at 500 and 650 nm can be achieved, which meets the requirements of plant growth, and the luminescence colour can be tuned from cyan to white and finally to red by changing the ratio of Mn2+ to Eu2+. The internal quantum efficiency of CNYPO:0.18Eu2+,0.18Mn2+ is 76.8% under 340 nm excitation. The introduction of Mg2+ can regulate the occupation sites of Eu2+ and the emission peak position, improve the responsiveness to the plant absorption spectra, and tune the luminescence colour to white. Finally, a white light-emitting diode (WLED) device fabricated using CNYPO:0.18Eu2+,0.18Mn2+,2.16Mg2+ on a 365 nm chip has a high colour rendering index of 89.0 and a low correlated colour temperature of 3580 K, indicating that the prepared phosphor has potential applications in plant lighting and WLEDs.
研究领域:
材料科学
·
光学工程
·
农业科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2022
·Vol. 106
·期 2
·1216-1229
·
IF 4.186
Guangtao Lu,Yichao Wang,Siqi Piao,Jinsu Zhang,Xizhen Zhang,Xufeng Zhou,Yongze Cao,Xiangping Li,Baojiu Chen
The excellent narrow-band emitters, especially the green ones, are regarded as a pivotal research direction for light-emitting diodes (LED) backlights in liquid-crystal displays (LCDs). A nearly single-peak green emission centered at 513 nm with a full width at half maximum of 28 nm is reached in KAl 11 O 17 :0.1Eu 2+ , 0.15Mn 2+ phosphor via nearly 100% energy transfer (ET) efficiency, and the extended X-ray absorption fine structure analysis elucidates its mechanism, which is that Eu 2+ and Mn 2+ are constrained to form Eu 2+ –Mn 2+ pairs with a small distance 3.7 Å caused by the local environment relaxation inducement. Meanwhile, by creating an unhindered energy flow between Eu 2+ , Mn 2+ and K + /O 2− defect levels through ET and multilevel electron trapped and recombination process, the KAO:Eu 2+ , Mn 2+ phosphors perform superb photoluminescence property with a high color purity of 83%, an excellent thermal stability (94%@200°C), and unexceptionable internal and external quantum efficiencies of 91.7% and 66.4%, which all are superior to characteristics of commercial β-SiAlON:Eu 2+ phosphor. Moreover, the white LED fabricated using KAO:Eu 2+ , Mn 2+ to provide green component shows a wide color gamut of 105% National Television System Committee. These results indicate a potential for an application of our material in LCD–LED backlights, and the design of such local relaxation-induced structure provides a significative reference to develop the new narrow-band emitters.
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
OPTICAL MATERIALS
·
2023
·
IF 3.9
Bojun Lin,Yanjie Zhang,Zihan Zhao,Herui Zhao,Jingjie Yu
Eu 2+ /Eu 3+ co-doped Ca 5 (PO 4 ) 3 F (FAP) phosphors with tunable color of red/blue (R/B) emission were successfully synthesized by the two-step method for potential applications in light-emitting diodes (LED). Eu 2+ (or Eu 3+ ) single-doped and Eu 2+ /Eu 3+ co-doped FAP all showed pure hexagonal FAP crystal with space group P6 3 /m, indicating the occupation of Ca sites by Eu 2+ and Eu 3+ ions. Typically, Ca 5 (PO 4 ) 3 F: Eu 2+ phosphors exhibited a broad blue emission band at 451 nm under 293 nm excitation and Ca 5 (PO 4 ) 3 F: Eu 3+ samples emitted strong orange-red light at 596 nm, 615 nm and 620 nm under 394 nm excitation. Further, Eu 2+ /Eu 3+ co-doped FAP phosphors obtained by the two-step method depicted the blue emission at 451 nm (Eu 2+ ions) and the orange-red emission (Eu 3+ ions) at 596 nm, 615 nm and 620 nm with an excitation wavelength of 365 nm (NUV). The tunable R/B ratio from 0.079 to 7.035 with various CIE chromaticity coordinate can be achieved by adjusting the recalcined temperature in the second step. Ca 5 (PO 4 ) 3 F: Eu 2+ , Eu 3+ sample can be packaged with green Lu 3 Al 5 O 12 (LuAG) phosphors by 365 nm chip (1 W) and the cold white light with CIE chromaticity coordinate (0.2815, 0.3485) (CRI: 73, CCT: 7973 K) is achieving. Based on Ca 5 (PO 4 ) 3 F: Eu 2+ , Eu 3+ and 25B 2 O 3 -10SiO 2 -35ZnO-6Li 2 O-12La 2 O 3 -12WO 3 (BS-glass) (in mol%) with strong mechanical strength as a great binder, the remote-excited color convertor (PiG: phosphor in glass) has been fabricated by screen printing technology for NUV-WLED application. Finally, by comparing the working temperature of PiG and pc-WLED at the same operating time, the working temperature of PiG was stable at 32 °C when remote excitation lighting was applied, which greatly avoided the phenomenon of “thermal quenching” for phosphors caused by high temperature under the operating of WLED. Thus, it was demonstrated that Eu 2+ and Eu 3+ co-doped Ca 5 (PO 4 ) 3 F phosphors with tunable red/blue emitting would be a highly potential candidate for NUV-WLED.
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 Materials Chemistry C
·
2020
·Vol. 9
·期 3
·1085-1096
·
IF 7.059
Jindi Wang,Shuai Huang,Mengmeng Shang,Peipei Dang,Hongzhou Lian,Jun Lin
In this work, using β-Ca3(PO4)2 as a structural model, a series of [Ca9Na3xY1−x(PO4)7 (CNYPO-I, 0 ≤ x ≤ 1/2) ← Ca3(PO4)2 → Ca9+yNa3/2−y/2Y(1−y)/2(PO4)7 (CNYPO-II, 0 ≤ y ≤ 1)] phosphors were prepared using a cationic heterovalent substitution approach. The substitution of Y3+ and Na+ for Ca2+ led to a redistribution of Eu2+ within the lattice and was accompanied by changes to the corresponding luminescence behavior. As the x and y values increased, the vacancies in the structure were gradually occupied by Na+ to form Na(4) sites that are conducive to Eu2+ occupation. When y = 1, the vacancies were completely occupied, and the Eu2+ emission peaks from Ca(1/2) and Ca(3) sites showed a significant blue shift. The underlying mechanism of that shift is discussed. The CNYPO-I (x = 0) sample displayed the best thermal stability; the effects of vacancies, thermal ionization and cross-over mechanism on thermal quenching are also discussed. As x and y increase, the thermal stability of the samples gradually decreased. Eu2+ and Mn2+ co-doped CNYPO-I (0 ≤ x ≤ 1/2) and CNYPO-II (0 ≤ y ≤ 1) phosphors achieved full coverage of the visible light region (400–800 nm). These white LEDs have relatively high color-rendering indexes (>80) and adjustable color temperatures from 2854–7000 K. This work provides an effective strategy for designing novel luminescent materials and realizing multi-site adjustment of activator ions.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2018
·
IF 2.732
Miaomiao Tian,Zhijun Wang,Zhenling Li,Jinge Cheng,Chao Wang,Xuanxuan Li,Zhiping Yang,Panlai Li
Here, using the safety raw materials Li 3 N, Sr 3 N 2 and Eu 2 O 3 instead of LiAlH 4 , SrH 2 and EuF 3 (besides AlN), the nitride phosphor SrLiAl 3 N 4 :Eu 2+ (SLA:Eu 2+ ) was synthesized in the glove box (O 2 <0.1 ppm, H 2 O<0.1 ppm) under continuous purified nitrogen flow. It avoids the dangerous synthesis and production environment negative factors caused by the dangerous materials of LiAlH 4 and SrH 2 . The luminescence properties of SLA:Eu 2+ with different aid-sintering additives (LiCl and SrF 2 ) were improved, such as red emission (~ 653 nm), narrow full-width at half-maximum (FWHM ~ 50 nm), highly luminous efficacy (23.6 lm/W) and superior thermal property . The narrow band emission of SLA:Eu 2+ fits well with the curve of human eye sensitivity and leads to excellent chromatic saturation. Moreover, the white light-emitting-diodes (LEDs) devices have been fabricated by combining a 450 nm blue chip with the commercial LCN630, LCL530 phosphor and as-prepared red-emitting phosphor SLA:0.004Eu 2+ , 0.1LiCl, 0.3SrF 2 which shows a greater color rendering index (Ra) value of 90.3 and low correlated color temperature (CCT) of 2726 K. Importantly, the luminous efficacy, the purity and R9 value increased up to 110.10 lm/W, 62.2% and 55, respectively. The results exhibit the materials with high luminous efficacy, low correlated color temperature and narrow band red emission, delivering the foundation for white LEDs.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2019
·Vol. 6
·期 12
·3604-3612
·
IF 5.934
Lili Wang,Xiaoying Kong,Peng Li,Weiguang Ran,Xuefang Lan,Qian Chen,Jinsheng Shi
Phosphors with high color purity and brightness are strongly desired for applications in areas such as solid-state lighting and displays. Herein, a new narrow-band intense green-emitting phosphor, Eu2+ doped CsKNaLi(Li3SiO4)4 (CKNLLSO) with a full width at half maximum of 55 nm, is reported. The substitutions of Eu2+ on three monovalent cations Na+, K+, and Cs+ resulted in three Gaussian emission bands. The barycenter energy of Eu2+ 4f65d configuration was calculated using a semi-empirical formula and compared with the experimental value. The rigid tunnel structure and luminescence concentration quenching were also analyzed to judge site occupation. The crystal and band structures of the host compound were characterized and calculated with the aid of Rietveld refinement and density functional theory, respectively. The CKNLLSO:Eu2+ phosphor exhibits relatively high thermal stability even if the temperature is increased to 190 °C. The optical properties of green and white LEDs fabricated by mixing the optimized CKNLLSO:4%Eu2+ phosphor without or with commercial blue and red phosphors were investigated. The detailed discussion about the relationship between the rigid tunnel structure and PL properties of CKNLLSO:Eu2+ will serve as a guide to develop new oxide-based narrow-band phosphors. All the results imply the great potential of Eu2+ doped CKNLLSO phosphors for applications in the field of backlighting or pc-wLEDs.
研究领域:
材料科学
·
光电学
·
固态照明
·
发光材料
✓ 已验证
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2017
·
IF 2.084
Guanghao Li,Yang Zhao,Jiao Xu,Zhiyong Mao,Jingjing Chen,Dajian Wang
Two strategies, deviation of stoichiometry and addition of flux, were employed in this work to suppress the emergence of AlN impurity in the synthesis of CaAlSiN 3 :Eu 2+ phosphors under condition of atmospheric pressure. The influence of Al atoms deviation from ideal stoichiometry and SrF 2 flux addition on the suppression of AlN impurity and their resultant photoluminescence properties are investigated for CaAlSiN 3 :Eu 2+ phosphors. For a special Eu 2+ doping concentration (0.02 mol), AlN impurity was suppressed effectively when Al element deviation is 0.2 mol (CaAl 0.8 SiN 3 ) and the SrF 2 flux addition is 7 wt% during preparation of CaAlSiN 3 :Eu 2+ phosphors, respectively. The luminescent properties of CaAlSiN 3 :Eu 2+ phosphors are found to be enhanced significantly owing to the suppression of AlN impurity. In addition, the suppression mechanisms of AlN impurity in atmospheric pressure-synthesized CaAlSiN 3 :Eu 2+ phosphors are discussed. These results indicate the promising prospect for our proposed strategies in preparing high performance CaAlSiN 3 :Eu 2+ phosphors under the condition of atmospheric pressure.
研究领域:
材料科学
·
无机化学
·
固体发光
·
功能材料
·
光电子学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）