JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2021
·
IF 8.128
Nan Ma,Wei Li,Balaji Devakumar,Zongjie Zhang,Xiaoyong Huang
White light-emitting diodes (LEDs) are widely used in lighting and display devices, and the exploration of phosphors with excellent luminescence performance and good stability is the key to the development of white LEDs. In this work, we reported novel near-UV-excited green-emitting Ca 2 LuHf 2 (AlO 4 ) 3 :Ce 3+ ,Tb 3+ garnet phosphors with efficient Ce 3+ → Tb 3+ energy transfer. The CLHA:Ce 3+ ,Tb 3+ green phosphors were successfully synthesized by a high-temperature solid-state method, and the phosphors were characterized by X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental mapping, photoluminescence excitation and photoluminescence spectra, the Commission International de I’Eclairage (CIE) chromaticity coordinates, quantum efficiency and temperature-dependent emission spectra. Due to the spin-allowed 4f → 5d transition of Ce 3+ ions, the CLHA:Ce 3+ ,Tb 3+ phosphors exhibited a strong broad excitation band in the 300–470 nm near-ultraviolet (near-UV) range. Under 408 nm excitation, the CLHA:Ce 3+ ,Tb 3+ phosphors showed strong green light with emission center at 543 nm. The mechanism of energy transfer from Ce 3+ to Tb 3+ ions was attributed to quadruple-quadruple interaction. Impressively, the internal quantum efficiency and external quantum efficiency of the optimal CLHA:0.02Ce 3+ ,0.5Tb 3+ green phosphors were measured to be 77.1% and 55.8%, respectively. Finally, using the CLHA:0.02Ce 3+ ,0.5Tb 3+ phosphors as green-emitting color converter, a near-UV-pumped white LED device was fabricated, and under 80 mA driving current the LED device demonstrated bright warm-white light with high color rendering index (93.7), low correlated color temperature (3574 K), CIE chromaticity coordinates (0.3922, 0.3633), and high luminous efficacy (29.35 lm/W).
研究领域:
材料科学
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光学工程
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF LUMINESCENCE
·
2018
·
IF 2.732
Wenzhi Wang,Jinkai Li,Zhengyang Zhang,Zongming Liu
The new systems of the (Gd 0.95- x Dy 0.05 Tb x ) 2 (WO 4 ) 3 ( x = 0–0.1) and (Gd 0.95- y Dy 0.05 Eu y ) 2 (WO 4 ) 3 ( y = 0–0.2) phosphors have been successfully obtained using the hydrothermal method at 900 °C in this work. The crystal structure, morphology, PL/PLE spectra, fluorescence and decay analysis have been studied in detail via the combined techniques of XRD , FE-SEM, PLE/PL spectra and decay kinetic. The phase-pure of the (Gd 0.95- x Dy 0.05 Tb x ) 2 (WO 4 ) 3 and (Gd 0.95- y Dy 0.05 Eu y ) 2 (WO 4 ) 3 with good dispersions have been formed at the lower sintering temperature of 900 °C. Under 273 nm and 270 nm excitation (the 6 P 7/2 → 8 S 7/2 transitions of Gd 3+ ), the Gd 2 (WO 4 ) 3 :Dy 3+ /Tb 3+ and Gd 2 (WO 4 ) 3 :Dy 3+ /Eu 3+ phosphors exhibit both Dy 3+ (yellow, at 574 nm) and Tb 3+ (green, at 547 nm) as well as Dy 3+ (yellow, at 574 nm) and Eu 3+ (red, at 616 nm) emissions, respectively. The presences of WO 4 2- , Gd 3+ and Dy 3+ excitation bands on the PLE spectra by monitoring the Tb 3+ and Eu 3+ emissions directly provide an evidence of energy transfer of WO 4 2- →Tb 3+ , Gd 3+ →Tb 3+ and Dy 3+ →Tb 3+ , as well as WO 4 2- →Eu 3+ , Gd 3+ →Eu 3+ and Dy 3+ →Eu 3+ , respectively. The quenching concentrations of both two systems are determined to be 7 at% ( x = 0.07 for Tb 3+ ) and 10 at% ( y = 0.10 for Eu 3+ ), and the quenching mechanisms of both two systems are mainly due to the Tb 3+ -Tb 3+ and Eu 3+ -Eu 3+ energy transfers, respectively. The color-tunable emission can be achieved though adjusting the relative content ratios of Dy 3+ /Tb 3+ or Dy 3+ /Eu 3+ , which has been verified by the CIE chromaticity coordinates analysis. The energy transfer efficiencies of Dy 3+ →Tb 3+ and Dy 3+ →Eu 3+ have been calculated, and the energy transfer mechanisms have been analyzed in detail. The (Gd 0.95- x Dy 0.05 Tb x ) 2 (WO 4 ) 3 and (Gd 0.95- y Dy 0.05 Eu y ) 2 (WO 4 ) 3 phosphors with color-tunable emission may have a potential application for w-LEDs.
研究领域:
材料科学
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光学
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DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2023
·
IF 3.6
Yanting Liu,Yanzhu Wang,Lili Meng,Qi Pang,Hua Yao,Qian Chen,Sidi Ye,Yanting Li,Minyi Zheng
Herein, we successfully obtained Ho 3+ and Ag + -codoped Cs 2 NaBiCl 6 halide double perovskites (DPs) via a hydrothermal method , which exhibit orange-red broadband self-trapped excitons (STE) emission and visible (Vis) and near-infrared (NIR) narrow band emission attributed to Ho 3+ f-f transition, under 360 nm excitation. Compared to the single Ho 3+ -doped sample, the Vis PL intensity of the codoped sample was increased by nearly 13.8 times, and an enhanced photoluminescence quantum yield (PLQY) of 87.45 % was achieved. The PL enhancement is attributed to the partial substituting of Na + with Ag + , leading to an efficient STE emission, and the more energy transition from STE to Ho 3+ . Moreover, the synthesized phosphor exhibits good stability in thermal and atmospheric environments. White light-emitting diode (WLED) is fabricated by employing Cs 2 Na 0·997 Ag 0·003 Bi 0.935 Ho 0.065 Cl 6 on near-ultraviolet (n-UV) LED chips, achieving a color rendering index (CRI) of 95.0 and correlated color temperature (CCT) of 3814 K. Anti-counterfeit patterns and the application for night vision monitoring were also discussed. This study inspires the designing of high-quality phosphors of rare earth-doped DPs and expands the multi-domain luminescence applications of halide DPs.
研究领域:
材料科学
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光学工程
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稀土材料
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DOI
高影响因子
JOURNAL OF FLUORESCENCE
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2024
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IF 2.6
Zha Jiahao,He Chongjun,Chen Fangzhou,Wang Hongwei,Dong Biao,Liu Lijuan,Xia Mingjun,Deng Chenguang,Li Qian,Lu Yuangang,Chen Huiting
Oxide matrix red-emitting phosphors are deemed as excellent color converters for white light emitting diodes (WLEDs) and laser diodes (LDs). Manganese-doped MgAl 2 O 4 powder was synthesized by a solid-state reaction method at different sintering temperatures. Microstructure shows that grain size is mainly in the range of 0.2–5 μm, and grain agglomeration occurs with increased sintering temperature. XPS analysis indicates that the doped Mn ion exhibits a valence state of + 4 within the MgAl 2 O 4 matrix. The diffraction peak of the phosphors is shifted by the sintering temperature, which affects lattice constant. Upon excitation by 300 nm ultraviolet light, the samples emit asymmetric broadband red light within the range of 620–720 nm, attributed to Mn 4+ ion’s transition from 2 E g to 4 A 2g states. With the increasing temperature, the main emission peak shifts from 677 nm to 650 nm, ascribed to the change in energy level ( 2 E g ) resulting from the reduction of Al 2 O 3 phase. Crystal field theory confirmed that Mn 4+ ions are within a strong crystal field environment created by MgAl 2 O 4 matrix. By affecting particle size and crystallinity, the sintering temperature influences the fluorescence lifetime of the Mn 4+ ion. Notably, these red-emitting phosphors exhibits remarkable thermal stability as their emission intensity remains approximately at 58% of initial intensity even at elevated temperature (435 K). Consequently, Mn 4+ : MgAl 2 O 4 red-emitting phosphors with high thermal stability render them promising candidates for WLED applications.
研究领域:
材料科学
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光学
✓ 已验证
DOI
高影响因子
Photonics
·
2023
·Vol. 10
·期 10
·1113
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IF 2.4
Junhu Cai,Xiaogang Chen,Wenyan Zhang,Longwen Yang,Zexi Lin,Wenxiao Zhao,Yun Ye,Sheng Xu,Tailiang Guo,Enguo Chen
Owing to their composition-tunable and narrow emissions and high photoluminescence quantum yield (PLQY), inorganic halide perovskite quantum dots (IPQDs) are a promising option for wide color gamut displays. However, their practical applications have been limited by their lattice structure instability and surface defect states. Herein, CsPbBr3:KBF4@SiO2with improved stability and optical properties is successfully synthesized with a two-step optimization of fluorine (F) anion doping and SiO2in situ coating. Compared with bromide (Br), higher electronegativity and a smaller radius of F lead to stronger binding energy with Pb2+. Also, F anions can occupy surface Br vacancies. Then, benefiting from the acidic environment provided by BF4−hydrolysis, tetraethyl orthosilicate (TEOS) can be more easily hydrolyzed on the CsPbBr3:KBF4surface to generate SiO2coating, thus further passivating lattice defects and improving environmental stability. Importantly, the PLQY of CsPbBr3:KBF4@SiO2achieves 85%, and the stability has been greatly improved compared with pure CsPbBr3. Finally, CsPbBr3:KBF4@SiO2/PDMS, CsPbI3/PDMS, and CsPbCl3/PDMS composites with narrow emissions are applied to replace traditional phosphors as color converters for direct-view light-emitting diode (LED) displays or liquid crystal display (LCD) backlights. The color gamut reaches 118.22% under the NTSC standard. Concerning the display field, it suggests likely applications in the future.Keywords:CsPbBr3;KBF4;SiO2;wide color gamut;liquid crystal displays;LED displays
研究领域:
材料科学
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光学工程
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显示技术
✓ 已验证
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2020
·Vol. 7
·期 18
·3371-3378
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IF 5.958
Yang Zhou,Xiaoming Wang,Cuiping Wang,Tian Zhang,Yonggang Wang,Fan Dou,Huan Jiao
A novel red fluoride phosphor BaNbF7:Mn4+ was synthesized via the conventional co-precipitation method. The structure and luminescence properties of BaNbF7:Mn4+ were investigated and discussed under various conditions. The BaNbF7:Mn4+ phosphor shows strong ZPL emission intensity at about 630 nm under ultraviolet (UV) and blue light excitation. It originated from the highly distorted Mn4+ octahedral coordination environment in the C3v group symmetry surrounding. A WLED fabricated with a blend of YAG:Ce3+ and the BaNbF7:Mn4+ phosphor exhibits a low color temperature (CCT = 3715 K) and a high color rendering index (Ra = 81.2), indicating its potential for application as a red phosphor for WLEDs.
研究领域:
材料科学
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光学
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DOI
高影响因子
Journal of Materials Chemistry C
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2023
·Vol. 11
·期 23
·7611-7618
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IF 6.4
Xiaoxuan Guo,Bomei Liu,Rongyi Kuang,Weijiang Gan,Lin Huang,Jing Wang
Cr-activated phosphor-converted light sources have attracted widespread attention in various applications based on near-infrared (NIR) spectroscopy. Unfortunately, Cr ions usually face the issue of multivalence and typically exist in the valence of +3, which gives the emission mainly at NIR-I (700–1000 nm) and greatly limits its potential application. In this study, we propose the control strategies of site occupancy confinement and sintering atmosphere to synthesize Cr4+-activated Li2SrGeO4 (LSGO:Cr4+) phosphors. Interestingly, the as-optimized LSGO:Cr4+ achieves a NIR broadband emission peak at 1170 nm with an FWHM of 208 nm upon excitation at 680 nm and exhibits excellent thermal stability and high efficiency with the external quantum efficiency of 30.0%. Furthermore, the as-fabricated LSGO:Cr NIR phosphor-converted light emitting diode (NIR pc-LED) device shows a high power of up to 69.1 mW at 550 mA. Furthermore, as NIR-II (1000–1700 nm) light source, the phosphor successfully distinguishes deuterium and non-deuterium reagents. For example, the quantitative detection of H2O in heavy water (D2O) is demonstrated by NIR spectroscopy with a limit of detection (LOD) of 0.47 vol%. Our findings will open up a new avenue to develop novel Cr4+-activated NIR-II phosphors and NIR-II light sources.
研究领域:
材料科学
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光学工程
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分析化学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2019
·Vol. 136
·期 32
·47834
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IF 2.188
Jianjun Chen,Zien Fu,Hengchao Huang,Zhonghua Chen,Xingrong Zeng
A facile route was introduced to prepare homogeneous silicone resin doped with titanium hybrid with high refractive index (RI). Specifically, the hybrids were obtained from the transesterification of hydroxyl-phenyl-vinyl silicone resin and titanium isopropoxide under anhydrous conditions. The structures of hybrid silicone and their corresponding intermediates (hydroxyl-phenyl-vinyl silicone) were characterized by nuclear magnetic resonance spectroscopy ( 1 H NMR, 29 Si NMR) as well as Fourier transform infrared spectroscopy (FTIR). The hybrids had a transmittance of more than 88% ranging from 450 nm to 800 nm, a high RI of 1.585, and a lower water vapor permeability of 3.58 g /m 2 .24h. Results from FTIR showed intensity of Ti-O-Si bond in hybrid decrease with extended the storage time, but the properties of cured hybrids including optical, mechanical, and gas permeability were not influenced. Compared to chips encapsulated with pure silicone, the luminous efficiency of the chips encapsulated with hybrids was improved from 138.6 lm/W to 156.4 lm/W. The thermal shock and hygrothermal aging test also demonstrated the hybrids had a wide range application in light-emitting diode (LED) packaging. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47834.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2017
·Vol. 5
·期 34
·8828-8835
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IF 5.256
Yibo Chen,Kuanglun Wu,Jin He,Zhengbin Tang,Jianxin Shi,Yiqin Xu,Zhao-Qing Liu
The rational and delicate synthesis of Mn4+ activated red-emitting oxide phosphors with high photoluminescence quantum yield (PLQY) and photo-stability for developing high-quality w-LEDs still remains a great challenge. Herein, we demonstrate a simultaneous ion co-substitution design strategy to synthesize a red-emitting Lu3Al5O12:Mn4+,Mg2+ garnet phosphor delicately with the assistance of MgF2. The Mn4+ activated garnet phosphor exhibits superior moisture resistance properties and high PLQY (ca. 72.41%), which emits a bright and narrow-band red light peaking at ∼670 nm due to the 2E–4A2 spin-forbidden transition of Mn4+ upon UV excitation. Remarkably, MgF2 as a charge compensator & flux can not only accelerate the solid state reaction, but also greatly improve the emission intensity. Furthermore, by employing the as-prepared Lu3Al5O12:Mn4+,Mg2+ as a red component, we fabricate a warm w-LED with a high color rendering index (Ra = 81.4) and low color temperature (CCT = 4766 K) based on a UV chip and commercial blue and yellow phosphors.
研究领域:
材料科学
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光学工程
✓ 已验证
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DOI
高影响因子
JOURNAL OF ELECTRONIC MATERIALS
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2018
·Vol. 47
·期 12
·7497-7504
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IF 1.566
Zheng Jingxia,Wang Junli,Wang Yaling,Yang Yongzhen,Liu Xuguang,Xu Bingshe
A one-pot microwave-assisted hydrothermal approach was developed to quickly synthesize yellow fluorescent carbon dots (CDs) using o -phenylenediamine and urea as raw materials. The optimized reaction temperature of 140°C and reaction time of 10 min were adopted to synthesize the CDs with photoluminescence quantum yield of 4.23%. The as-prepared CDs exhibit yellow fluorescence ( λ em ∼ 563 nm) and an excitation-independent PL emission in the region of 440–700 nm. The CDs were combined with a blue chip ( λ ex = 420 nm) to fabricate white light-emitting diodes (WLEDs) and realize white light emission. The WLED has the color coordinates of (0.30, 0.30) and the correlated color temperature of 7915 K, which is suitable for office and outdoor illumination. The results demonstrate that as-obtained CDs can be a promising candidate as yellow-emitting phosphors for WLEDs.
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
Materials Today Chemistry
·
2022
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IF 7.613
B. Han,X. Yang,J. Ren,L. Liu,E. Zhao,X. Zhu,J. Zhu,H. Ma,A. Li,P. Teng
Indoor artificial cultivation of plants is a novel technology applied to agriculture, and the emission band of luminescent materials can be matched with the needs of plants to promote plant growth. In this contribution, novel Mn 4+ doped Sr 2 GdTaO 6 (SGTO) deep-red phosphor was synthesized. This material was characterized, in detail, by X-ray diffractometer, SEM, and photoluminescence emission spectra. Sr 2 GdTaO 6 :Mn 4+ (SGTO:Mn 4+ ) can be effectively excited by near-ultraviolet (NUV) light, and the broadband emission of deep-red light matches the absorption band of plant phytochromes P R and P FR . The optimum doping concentration of Mn 4+ in SGTO was 0.6 mol%, and the concentration quenching mechanism was attributed to dipole-quadrupole ( d - q ) electric interaction. The photoluminescence emission intensity of SGTO:0.006Mn 4+ at 423 K is 80.6% of that at room temperature and the internal quantum efficiency of SGTO:0.006Mn 4+ is 36.09%. Finally, the performance of the commercial 440 nm light-emitting diode chip/SGTO:0.006Mn 4+ encapsulated light-emitting diode device was stable and can meet the needs of plants for the blue and red light. The results showed that SGTO:0.006Mn 4+ deep-red phosphor is expected to be a phosphor suitable for indoor plant growth lighting.
研究领域:
农业科学
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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
Laser & Photonics Reviews
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2022
·Vol. 17
·期 3
·2200639
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IF 10.947
Shuyang Bao,Yueyuan Liang,Cong Zhao,Luhan Wang,Xiaojuan Liang,Weidong Xiang
Solid-state white lighting applications with high brightness, low power consumption and long operating life have gradually dominated the modern industrial illumination market. For applications in white light-emitting diodes (WLEDs) and white-lighting laser diodes (WLDs), Phosphor-in-Glass (PiG), owing to its facile process, high efficiency and excellent chromaticity tunability, stands out as an optimal choice among various types of color converters. Currently, research in yellow-emitting Y 3 Al 5 O 12 :Ce 3+ (YAG: Ce) phosphors combined with different glass system has reached a mature stage and the poor illumination is a major bottleneck. Moreover, to realize high-quality white lighting, exploiting full-color PiGs is of great importance for its commercialization. Herein, the multicolour PiGs their successfully obtained by deliberately matching different color-emitting phosphors with the glass matrix. Glass composition selection rules for specific phosphors their proposed based on investigations of glass protection mechanism and the corrosion reaction between phosphors and glass matrix. In addition, an astonishing YAG: Ce PiG phenomenon (zero thermal quenching) is founded and discussed. As for practical applications, high-quality 5-W chip-on-board (COB) WLEDs their constructed by utilizing simple matches of colorful PiGs. Assembled WLDs modules also rendered a high-efficiency and stable lighting source. These results dramatically inspire the development of high-quality solid-state white lighting 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
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