JOURNAL OF RARE EARTHS
·
2024
·Vol. 43
·期 10
·2100-2107
·
IF 5.2
Jing Yan,Junyu Hong,Xiaohui Li,Bojana Milićević,Lei Zhou,Chunyan Jiang,Mingmei Wu
Nowadays, high-quality phosphor-converted white light-emitting diodes (pc-WLEDs) ought to include cyan-emitting phosphors allowing for full-spectrum light similar to sunlight. Herein, we report a garnet-structured Ce 3+ -doped SrLu 2 Ga 1.5 Al 2.5 SiO 12 (SLGASO) phosphor that significantly compensates for the absence of cyan light, known as the “cyan cavity”. The SLGASO host crystallizes into a cubic structure with the I a 3 ¯ d space group. The cell parameters were determined using Rietveld refinement. Under 430 nm blue excitation, SLGASO:Ce 3+ emits intense cyan-green light in the 450–700 nm wavelength range. The representative SLGASO:0.07Ce 3+ phosphor has an internal quantum efficiency (IQE) of 95.4% and excellent thermal stability, remaining 92.7% of its initial emission intensity at 152 °C. After 155 d of immersion in water, the luminous intensity of SLGASO:0.07Ce 3+ remains constant, confirming its waterproofness. Furthermore, a pc-WLED device with luminous efficiency (LE) of 101.58 lm/W, color rendering index ( Ra ) of 91, correlated color temperature (CCT) of 4536 K, and Commission Internationale de L'Eclairage (CIE) chromaticity coordinates of (0.3555, 0.3390) was fabricated by combining as-prepared cyan-green-emitting SLGASO:0.07Ce 3+ , yellow-emitting Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ ), and red-emitting (Ca,Sr)AlSiN 3 :Eu 2+ phosphors, as well as a 450 nm blue chip. These findings indicate that SLGASO:0.07Ce 3+ phosphor can bridge the cyan gap and improve the performance of as-fabricated full-visible-spectrum WLEDs.
研究领域:
材料科学
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光学材料
·
固态照明
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无机化学
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光电子学
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2024
·
IF 3.3
Changlin Li,Siyu Cheng,Yilian Ran,Xiya Miao,Dongze Li,Yangyu Su,Yuchen Yang,Xianchao Du,Xiang Liu,Ruijin Yu
The novel orange-red emitting K 5 Y(MoO 4 ) 4 : x Sm 3+ (KYMO: x Sm 3+ ) (1 mol% ≤ x ≤ 35 mol%) phosphors were synthesized through solid-phase reaction. The KYMO:Sm 3+ phosphors were mainly analyzed for purity phase, luminescence properties, and thermostability. Under 403 nm excitation, KYMO:10 mol%Sm 3+ possesses four distinct emission peaks. The dominant emission peak is situated at 645 nm, corresponding to the 4 G 5/2 → 6 H 7/2 electron transitions. With x = 10 mol%, the KYMO: x Sm 3+ phosphor has the optimal doping concentration. The color purity reaches as high as 99.9 %. KYMO:10 mol%Sm 3+ presents good thermostability with T 0.5 > 480 K and resistance to color drift (Δ E = 0.012 at 420 K). The lifetime for KYMO:10 mol%Sm 3+ is 1.16 ms. The internal quantum efficiency (IQE) reaches 62.74 %. At 480 K, the maximum temperature sensing sensitivities of the FIR of I 564 /I 599 are 5.19 × 10 −4 ( S a ) and 18 % ( S r ). The assembled WLED displays an excellent color rendering index (CRI, R a ) of 94, Commission International de L′ Eclairage (CIE) coordinates (0.333, 0.346), and a correlated color temperature (CCT) of 5464 K. In summary, KYMO:Sm 3+ phosphors possess great promise for high CRI white-light-emitting diodes (WLEDs) and potential feasibility for temperature sensing.
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
DALTON TRANSACTIONS
·
2023
·Vol. 52
·期 17
·5587-5596
·
IF 4
Zhijian Liao,Yan Li,Jiaxing Zuo,Guang Chen,Heng Liang,Shihao Wu,Jiaqing Peng,Xinyu Ye
For high-efficiency lighting and wide color gamut backlight display, high-quality narrow-band red phosphors for WLEDs are still in high demand. Herein, a novel red-emitting fluoride phosphor Cs2NaGaF6:Mn4+ was successfully synthesized by a simple two-step co-precipitation method and exhibits ultra-intense zero-phonon lines (ZPLs) and long wavelength phonon sidebands under 468 nm blue light irradiation. The ZPL emission peak of Cs2NaGaF6:Mn4+ was located at 627 nm, which is much stronger than its υ6 vibration peak, more matchable with the eye-sensitive region of humans, and beneficial for obtaining higher luminous efficiency of WLEDs. Interestingly, the υ6 vibration peak of this red phosphor is at 636.5 nm, which is larger than that of the common fluoride phosphor A2BF6:Mn4+ (usually at about 630 nm, represented by K2SiF6:Mn4+) at about 6.5 nm. Thanks to the longer wavelength of the υ6 vibration peak, the chromaticity coordinates (0.7026, 0.2910) with a larger x-coordinate value were realized, leading to a potentially wider color gamut of WLEDs. In addition, this phosphor has high thermal stability and its emission intensity at 423 K remains 93.7% of the initial intensity at room temperature. The lumen efficiency of WLED1 packaged with a mixture of Cs2NaGaF6:Mn4+ and YAG:Ce3+ on the InGaN blue chip is 115.7 lm W−1 with the color temperature (Tc) = 3390 K and the colour rendering index (Ra) = 92.5 under 20 mA driving current. The chromaticity coordinates of WLED2 packaged with Cs2NaGaF6:Mn4+ and β-SiAlON:Eu2+ on the InGaN blue chip are (0.3149, 0.3262) and the calculated color gamut is up to 118.4% (NTSC). These results indicate that Cs2NaGaF6:Mn4+ red phosphors have promising applications in the high-quality lighting and display fields.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 23
·27513-27523
·
IF 2.478
He Youyi,Liu Jun,Gao Yalei,Yan Lijuan,Lv Fengzhen,Liu Fuchi,Long Lizhen
Mn 4+ -activated phosphors have become a hotspot in the development of inorganic red phosphors due to the fascinating photoluminescent properties. Herein, the synergetic manipulation of the flux effect and charge compensation was employed to improve the performance of Mn 4+ -activated CaAl 12 O 19 red phosphors. The crystallinity was improved by appropriate Zn 2+ -doping, while nonradiative transition between Mn 4+ ions is reduced by charge compensation of the formation of Mn 4+ –Mg 2+ pairs with Mg 2+ dopants. Thus, the emission of Mn 4+ -activated CaAl 12 O 19 red phosphors has been remarkably enhanced. The low probability of nonradiative transition between Mn 4+ ions was demonstrated by the thermal stability analysis. To depict the luminescent process, the crystal-field strength ( D q ), and Racah parameters ( B and C ) were calculated to determine the sequence of the energy levels. Meanwhile, the warm WLEDs with high CRI and low CCT were obtained using the prepared phosphors as red-emitting composition. Our results clearly suggested that the synergetic strategy by combining the flux effect and charge compensation is an effective method to enhance the luminescence of CaAl 12 O 19 :Mn 4+ , and CaAl 12 O 19 :Mn 4+ /Zn 2+ /Mg 2+ red-emitting phosphors, which have potential application value in warm WLEDs.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2020
·Vol. 8
·期 41
·14548-14558
·
IF 7.059
Zhihao Wang,Qinghong Meng,Chunyun Wang,Dianyuan Fan,Yu Wang
Phosphor-converted white light-emitting diodes (pc-WLEDs) integrated with deep UV chips and single-component white light-emitting phosphors have attracted widespread research interest recently. (Y,Tb,Eu)NbO4 nanophosphors with full-color emission properties were achieved in this work by a facile calcination-assisted hydrothermal method, and the elaborately designed white light-emitting (Y0.988Tb0.010Eu0.002)NbO4 phosphor was successfully applied to a 275 nm chip excited pc-WLED with a relatively low correlated color temperature (CCT) of 5517 K and a high color-rendering index (CRI) of 86.7. Through a comprehensive characterization by XRD, elemental analysis, FE-SEM, TEM, TG, FT-IR, UV-vis, and optical spectroscopy, the YNbO4 nanophosphor with optimal PL properties was evidenced to be obtainable through calcining the hydrothermally crystallized precursor at 1000 °C. The quenching concentrations of Tb3+ and Eu3+ in YNbO4 were determined to be ∼4 and 5 at%, respectively, and the efficiency of the NbO43− → Tb3+ energy transfer was calculated to be ∼47.93%. Upon excitation at 260 nm, the ternary (Y,Tb,Eu)NbO4 phosphor simultaneously displays blue NbO43−, green Tb3+, and red Eu3+ emissions. Benefiting from the NbO43− → Tb3+ → Eu3+ energy transfer, full color emission was achieved via adjusting the Tb3+ and Eu3+ concentrations in (Y,Tb,Eu)NbO4. The white light-emitting (Y0.988Tb0.010Eu0.002)NbO4 phosphor with color coordinates of (0.336, 0.334) can maintain its emission color and ∼67% of its overall emission intensity at 150 °C, indicating that the phosphor is highly promising for application in deep UV chip-based pc-WLEDs.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2026
·
IF 6
Tianen Guo,Kexin Zhang,Xinyi Zhang,Junzhe Yuan,Ruihua Huang,Yanping Liu,Mubiao Xie,Ruijin Yu
Double-scheelite-structured red-emitting phosphors Gd 2 GeWO 8 (GGWO): x Eu 3+ ( x = 0 mol%-80 mol%) were synthesized via high-temperature calcination. Under 394 nm excitation, the GGWO:Eu 3+ phosphors presented four prominent emission bands, with the strongest peak located at 615 nm ascribed to the 5 D 0 → 7 F 2 electric dipole transition of Eu 3+ ions. Luminescence and lifetime analyses showed that nearest-neighbor ion interactions induced concentration quenching. The optimal doping concentration was 50 mol%. Based on Judd-Ofelt theory, the intensity parameters ( Ω 2 = 6.39 × 10 −20 m 2 , Ω 4 = 3.83 × 10 −20 m 2 ) were systematically calculated, revealing the asymmetric coordination environment and covalent nature of Eu 3+ ions within the GGWO host. The GGWO:50 mol%Eu 3+ phosphor showed remarkable thermal stability, exhibiting an activation energy of 0.336 eV and 90.38% luminescence intensity retained at 480 K. Its internal quantum efficiency reached 66.23%. All prepared phosphors possessed high color purity above 99.9%. The emission of the red LED fabricated with GGWO:50 mol%Eu 3+ phosphor overlapped well with the absorption spectra of typical plant photosynthetic pigments. Meanwhile, the fabricated white light-emitting diodes (WLEDs) achieved an excellent color rendering index of R a = 89, with CIE chromaticity coordinates (0.328, 0.324). Oleic acid (OA) modification effectively maintained luminescence performance and distinctly enhanced the resolution and contrast for latent fingerprint (LFP) and lip print imaging. The phosphors also exhibited potential performance in anti-counterfeiting inks. Benefiting from its versatile performance in plant-cultivation LEDs, WLEDs, personal identification, and anti-counterfeiting inks, this red-emitting phosphor can be regarded as a prospective candidate for numerous advanced optical applications.
✓ 已验证
DOI
高影响因子
Optical Materials Express
·
2022
·Vol. 12
·期 10
·4117-4132
·
IF 3.074
Zihan Zhao,Zihan Zhao,Ran Zhang,Ran Zhang,Hao Song,Yanjie Zhang,Yanjie Zhang,Yanjie Zhang,Xiuping Wu,Desheng Li,Bing Li,Bing Li
As blue emitting component in phosphor-converted white-light-emitting-diodes (pc-wLEDs) encapsulated with near-ultraviolet (NUV) chips, Eu2+ activated fluorapatite structure phosphors play key roles because of strong structural stability and excellent photoluminescent properties. A series of M5(PO4)3F: Eu2+ (M = Ca, Sr) samples have been newly prepared by deposition-precipitation process (DP) and exhibited a 6.7-fold enhancement of photoluminescent (PL) intensity due to the highly dispersed Eu2+ luminescence centers when compared with the reference samples synthesized via traditional solid-state reaction method (SSR). Detailed analysis of crystal field around Eu2+ and the nonlinear fitting of PL spectra concludes that Eu2+ activators with the 4f6 → 4f75d transition preferentially replace Ca1 in 4f symmetry sites leading to a fitted peak at 446 nm and the other sites of 6h are contributed to the 479 nm emitting of Eu2+ ions. Remarkably, tunable chromaticity of DP-M5(PO4)3F: Eu2+ with high color purity (97.79%) retains steady photoelectric converting and full width at half maxima (FWHM) of 46 nm in the device of DP-FAp: 0.03Eu2+@365 nm LED under diverse driving currents, which perfectly satisfies the requirements of excitation light source for oral photocuring materials. Further, the 123.4% color gamut of National Television System Committee (NTSC) standard is efficiently obtained by matching Sr5(PO4)3F: Eu2+, CsPbBr3 and Lu3Al5O12: Mn4+ phosphors with a 365 nm chip (1 W) to achieve high-quality white light (CRI value reaches to 86, CCT is 7107 K and CIE chromaticity coordinate arrives at (0.292, 0.376), indicating a potential candidate for dentistry curing light and high-quality NUV excited pc-wLEDs.
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
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Quansheng Wu,Yanyan Li,Yijie Wang,Hai Liu,Shanshan Ye,Lei Zhao,Jianyan Ding,Jiangcong Zhou
Investigating highly efficient narrow-band emission phosphors that have strong excitation bands in the near-ultraviolet (NUV) region is the main goal of the present light-emitting diode (LED) research, especially for Bi 3+ -activated phosphors. The naked 6s and 6p electrons of Bi 3+ are sensitive to the microenvironment, thus leading to broad emission bands, while most Bi 3+ -activated phosphors suffer from low absorption of NUV-LED chips. Here, we report on a narrow-band blue-emitting garnet-type phosphor of Sr 3 Lu 2 Ge 3 O 12 : Bi 3+ that is available for NUV-LED chips; its full width of the half maximum (FWHM) is limited to 40 nm, which is comparative to rare earth-activated phosphors, such as commercial blue phosphor BaMgAl 10 O 17 : Eu 2+ (FWHM ≈ 52 nm), and this phenomenon is extremely rare among most Bi 3+ -activated phosphors. The internal quantum efficiency (IQE) of Sr 3 Lu 2 Ge 3 O 12 : Bi 3+ can reach 57%. Moreover, it is interesting to find that Sr 3 Lu 2 Ge 3 O 12 : Bi 3+ also exhibits exalting cathodoluminescence properties and its narrow-band emission produces brilliant images with high color saturation. The significant luminescent properties of trivalent bismuth are ascribed to the compact and highly symmetrical crystal structure of Sr 3 Lu 2 Ge 3 O 12 ; thus, the discussion of the structure-property relations for Bi 3+ -activated Sr 3 Lu 2 Ge 3 O 12 is the most anticipated part of this work. The results pave the way for the design of better Bi 3+ -activated phosphors for use as white light emitting diodes (WLEDs) and field emission displays (FEDs).
研究领域:
材料科学
·
光学材料
·
固态照明
·
光子学
·
显示技术
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 20
·6077-6084
·
IF 6.641
Chunyan Jiang,Lihua Li,Mikhail G. Brik,Litian Lin,Mingying Peng
The poor moisture-resistant property of the commercial narrow band red-emitting K2SiF6:Mn4+ phosphor restricts its practical application in high performance warm WLEDs. Herein, we report epitaxial growth via simple ethanol-induced deposition to enhance the luminescence and moisture resistance of K2SiF6:Mn4+. Specifically, an appropriate amount of ethanol at the end of the synthesis leads to epitaxial growth of a K2SiF6:Mn4+ shell. The resultant K2SiF6:Mn4+@K2SiF6:Mn4+ presents higher photoluminescence intensity due to a high Mn4+ critical concentration in the K2SiF6:Mn4+ epitaxial shell. Furthermore, the epitaxial growth of the K2SiF6 shell on K2SiF6:Mn4+ is designed to conquer the moisture resistance. As expected, the formed K2SiF6:Mn4+@K2SiF6 retains 82% of the initial emission intensity after being immersed in water for 4 h and 90% after being exposed to high temperature and humidity (85 °C, 85%) for 10 days. By employing K2SiF6:Mn4+@K2SiF6 as a red phosphor, a packaged white LED exhibits excellent performance with a CRI of 96.5, a CCT of 2879 K and a luminous efficacy of 119.74 lm W−1. More importantly, this fabricated WLED device retains high luminous efficacy and undergoes minor chromatic coordinate changes when aged at high temperature and humidity (85 °C, 85%). Therefore, these findings not only illustrate the effect of ethanol addition on the photoluminescence intensity of Mn4+ doped phosphors in the synthesis process, but also provide a facile strategy to improve the moisture resistance of K2SiF6:Mn4+ for warm WLEDs in the future.
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
Materials Chemistry Frontiers
·
2019
·Vol. 3
·期 10
·2120-2127
·
IF 0
Qiang Zhang,Xicheng Wang,Zuobin Tang,Yuhua Wang
A novel blue-emitting phosphor, Na3ScSi2O7:Ce3+ (NSSO:Ce3+), was synthesized with a solid-state method at low temperature successfully. Its crystal structure, band structure, and photoluminescence and cathodoluminescence properties were researched in detail. The phase formation and the crystal structure were confirmed by powder X-ray diffraction analysis and the Rietveld refinement method, respectively. Under the excitation of n-UV light, the optimal NSSO:0.02Ce3+ phosphor can yield blue emission centered at 452 nm with a high quantum efficiency of 50.9%. The PL intensity of the NSSO:0.02Ce3+ phosphor remains at 71.46% of the initial value when the temperature is increased from room temperature to 150 °C, indicating good thermal stability. A WLED lamp was obtained by combining a 360 nm n-UV chip with Sr2SiO4:Eu2+, (Ca, Sr)AlSiN3:Eu2+ and NSSO:0.02Ce3+ phosphors, in which the color coordinates, CCT and CRI are (0.360, 0.348), 4409 K and 90.9, respectively. Moreover, under low voltage electron bombardment, the phosphor can emit blue emission with high luminescence intensity, current saturation and resistance. All the results indicate that the NSSO:Ce3+ phosphor shows much potential for the application of both WLEDs and field emission displays (FEDs). Our research has also offered a new insight and perspective that using Sc-based sorosilicates as host can be an appropriate strategy for developing excellent inorganic luminescence materials.
研究领域:
材料科学
·
光学工程
·
无机化学
·
固态照明
·
显示技术
✓ 已验证
DOI
Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 43
·13536-13547
·
IF 6.641
Dongjie Liu,Peipei Dang,Xiaohan Yun,Guogang Li,Hongzhou Lian,Jun Lin
Recently, controllable luminescence tuning and single-phased white light emission have been extensively studied to improve the luminescence performances of phosphors for white light-emitting diodes (WLEDs). In this work, the controllable photoluminescence tuning from bluish-green to red was successfully achieved in Bi3+,Eu3+-codoped Sr2−yBayLaGaO5 solid solutions, combining the effects of crystallographic site engineering and energy transfer. The phase composition and structural variation of the designed phosphors were thoroughly analyzed through X-ray powder diffraction (XRD) and Rietveld refinement. The effects of cation substitutions on the photoluminescence properties were investigated in detail and the corresponding mechanism was proposed. A regular red-shift of Sr2−yBayLaGaO5:0.02Bi3+ in the bluish-green region could be observed when Sr2+ was substituted by Ba2+, which is attributed to the crystal field splitting and nephelauxetic effect. The red-shift of emission of Ba2LaGaO5:0.02Bi3+ phosphor with gradually increasing excitation wavelength reveals that Bi3+ ions occupy different cation sites to form multiple luminescent centers. Besides, the efficient energy transfer was designed and successfully realized in Sr2−yBayLaGaO5:0.02Bi3+,zEu3+ (y = 0–2.0; z = 0–0.20) samples. The energy transfer efficiency can reach up to 88%, 91% and 77% at z = 0.20 for y = 0, 1.0 and 2.0, respectively. Moreover, the thermal quenching behaviors of the studied phosphors reveal that the codoping of Eu3+ could efficiently improve the thermal stability of Sr2LaGaO5:0.02Bi3+ phosphor. Finally, the WLED devices were fabricated by composing 370 nm UV chips and single-phased Sr2−yBayLaGaO5:0.02Bi3+,0.05Eu3+ (y = 0, 1.0, 2.0) phosphors. The as-fabricated devices presented relatively excellent EL performances, the color coordinates of which all locate in the warm white light region. These results indicate the as-prepared Sr2−yBayLaGaO5:Bi3+,Eu3+ phosphors can be potential candidates for color tuning and efficient single-phased white emission in UV-based WLED lighting applications.
研究领域:
材料科学
·
光学材料
·
固态照明
·
荧光粉化学
·
能量传递
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）