CERAMICS INTERNATIONAL
·
2020
·Vol. 46
·期 11
·17923-17928
·
IF 3.83
Jian Xu,Yang Yang,Ziquan Guo,Dennis Dan Corell,Baoli Du,Bingguo Liu,Haipeng Ji,Carsten Dam-Hansen,Ole B. Jensen
Recent studies revealed that both the Al 2 O 3 –Y 3 Al 5 O 12 :Ce (YAG:Ce) composite ceramic (YAG-CC) and single crystalline YAG:Ce (YAG-SC) possess very high luminescence-saturation thresholds (LSTs), which makes them promising for laser lighting applications. The present study is aimed to conduct a comparative investigation between YAG-CC and YAG-SC on aspects of the laser-pumped luminescence and the associated thermal behavior. The colorimetric and photometric properties (e.g. luminous flux/efficacy, correlated color temperature, and color rendering index) were investigated systematically, by conducting the measurements using a custom-built sphere-spectroradiometer system in the transmission mode. It was found that YAG-SC has a superior LST and it could maintain a high luminous efficacy (106 lm/W) under the irradiation of a 15.33 W blue laser , while the YAG-CC saturated at around 7.76 W. Moreover, by combining the thermal imaging data with the spectral variation of the YAG-CC, novel experimental insights into the origin of luminescence saturation were revealed and proposed as the “thermally-induced absorption saturation”.
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高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Wenlei Liu,Jianxing Shen,Qingle Pang,Tailin Wang,Xiujun Han
Cerium-doped yttrium aluminum garnet (YAG:Ce) based transparent ceramics have been widely used in fluorescent lighting as high-quality inorganic fluorescent conversion materials. This paper further explores the Mg 2+ -Si 4+ ions doped YAG:Ce transparent ceramics by combining the solid-phase reaction method with vacuum hot-pressure sintering and implementing protection measures against hot-pressure mold contamination, and also investigates the effect of different Mg 2+ -Si 4+ doping contents on the structure, transmittance and luminescence properties of the ceramics under hot-pressure sintering. In this work, pure-phase YMASG:Ce transparent fluorescent ceramics with a grain size of about 3-6 μm and clear and clean grain boundaries were obtained with an In-line transmittance of 67% at 800 nm. Under the excitation at 460 nm, the emission peak was red-shifted by 26 nm and the full width at half maxima (FWHM) was broadened with the increase of Mg 2+ -Si 4+ content, which shows that the Mg 2+ -Si 4+ ion pair effectively complements the absence of the red light component in the YAG:Ce emission spectrum. The optimized YMASG:Ce ceramics obtained high-quality warm white light with a low correlated color temperature (CCT) and a high color rendering index (CRI) under the excitation of the blue LED chip. This work proved the feasibility of vacuum hot-pressure sintering to prepare YMASG:Ce transparent fluorescent ceramics, and provided a new approach for studying YMASG:Ce-based ceramics, which was significant for the application of high-power visible laser illumination.
研究领域:
材料科学
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光学工程
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2026
·Vol. 46
·期 12
·118396
·
IF 6.3
Jun Gao,Rui Fang,Mengmeng Li,Zhicai Zhang,Shuyao Li,Yang lv,Zhiqiang Hou,Chao Wang,Yao Tang,Haikuo Wang
YAG:Ce nanophosphors are crucial for advanced micro-optoelectronic devices but are fundamentally constrained by the severe trade-off between size and photoluminescence quantum yield (PLQY). This limitation makes it challenging to prepare high-quality materials that meet both ultra-small size (< 50 nm) and high-PLQY requirements. In this study, YAG:Ce nanophosphors (< 50 nm) exhibiting a high PLQY of 64% were successfully prepared through a co-precipitation method guided by experimental design, representing a significant advance in the field. YAG:Ce nano transparent ceramic (Nano-TC) was fabricated via the high-pressure and low-temperature sintering (HPLT, 7.7 GPa and 150 ℃). The Nano-TC shows an integrated performance of ∼50% PLQY, 65.04% transmittance at 750 nm, and a Vickers hardness of 18.59 GPa, representing a 47.31% improvement over the single crystal. This study demonstrates a viable pathway for fabricating nano-sized YAG:Ce phosphors that concurrently achieve miniaturization and extremely high PLQY, and establishes HPLT sintering as an effective route for translating these nanocrystals into high-performance Nano-TC for next-generation lighting and display applications.
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2026
·
IF 6.3
Qirui Pang,Huibin Tu,Hao Xue,Tianliang Zhou,Shuxing Li,Rong-Jun Xie
YAG:Ce-Al 2 O 3 composite phosphor ceramics exhibit exceptional thermal and optical properties, demonstrating remarkable resistance to high-power laser excitation and highly promising for laser-driven solid-state lighting. However, due to limitations in understanding the effects of raw materials, fabricating densely structured and homogeneously distributed composite ceramics via tape casting remains a significant challenge. In this study, we investigated effects of particle size and content of raw powders on rheological properties of slurry, microstructure and optical properties of composite phosphor ceramics. The YAG:Ce-70 wt% Al 2 O 3 composite phosphor ceramic, prepared by using nano-sized Y 2 O 3 and Al 2 O 3 , showed fully densified and homogeneous microstructure and demonstrated optimal optical properties. Under excitation at a blue laser power density of 21.20 W·mm -2 , the YAG:Ce-70 wt% Al 2 O 3 ceramic with a thickness of 0.2 mm created white light with a luminous flux of 1496.05 lm and 141.14 lm·W -1 . This work paves an avenue to large-scale production of high-performance phosphor ceramics.
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高影响因子
International Journal of Applied Ceramic Technology
·
2016
·Vol. 14
·期 1
·22-30
·
IF 1.534
Rui Ma,Bing Lu,Huiqun Cao,Juguang Hu,Xianghua Zhang,Qi Qiu,Ruisheng Zheng,Zhongkuan Luo,Bai Xue
We report the use of YAG:Ce phosphor as the raw material to make thin and transparent phosphor films with pulsed laser deposition including the effects of heating temperature, target–substrate distances, annealing times, and annealing atmosphere on the YAG:Ce 3+ phosphor film crystal types and spectral properties. The results indicated that at a coating temperature of 350°C, the YAG:Ce 3+ phosphor film had the best crystallinity with an intact film and maximum fluorescence emission. The crystallinity and fluorescence emission intensity of the film gradually decreased as a function of increasing target–substrate distances. As the annealing time increased, the crystallinity and the fluorescence emission intensity of the film first increased and then decreased. The film made with 5 h of annealing had the best crystallinity and the highest fluorescence emission intensity. The crystallinity of the film annealed under air was higher than that made under nitrogen; the fluorescence intensity of the film under air was slightly lower than the film under nitrogen. The emission peak of the prepared film was at 523 nm when excited at 450 nm. This is slightly blue-shifted versus the emission of commercial phosphor powders. This study offers a theoretical basis for the development of transparent phosphor films.
研究领域:
材料科学
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光电子学
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薄膜技术
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发光材料
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高影响因子
JOURNAL OF LUMINESCENCE
·
2025
·
IF 3.6
Huanyu Zhao,Jinsheng Li,Yan Jiang,Yao Lu,Lei Wang,Yi Xie,Wenlong Zhou,Yang Li,Xudong Sun
(Y,Ce) 3 Al 5 O 12 (YAG:Ce) ceramic is considered to be a suitable phosphor converter with a high quantum efficiency and excellent thermal stability for laser-driven lighting. However, the lack of red emission in the spectrum of YAG:Ce leads to the poor color quality of white light under excitation of laser diodes (LDs). Although current solutions were investigated to improve the color rendering index (CRI), they inevitably cause the decreased luminous efficacies (LE). How to balance the two luminous properties is still troubling researchers. In this study, a novel composite structure with large YAG:Ce grains surrounded by fine YAG:Cr grains was obtained by the two-stage hot-pressing process. The energy transfer between Ce 3+ and Cr 3+ was reduced because they were in different phases due to the structural design, thus improving the red emission while avoiding a sharp decline in the yellow emission. Moreover, there was no reaction and difference in thermal expansion coefficient between two phases due to the same matrix of YAG. Furthermore, the reflection loss in YAG:Cr‒YAG:Ce composite ceramic was reduced compared to layered-structure ceramics. Therefore, the maximal CRI reached 71.3 and the maximal LE was 255.8 lm/W, indicating an excellent application prospect in laser-driven lighting.
研究领域:
材料科学
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光学工程
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高影响因子
JOURNAL OF LUMINESCENCE
·
2020
·
IF 3.28
Xing Cao,Shichang Sun,Bing Lu,Yan Liu,Rui Ma,Huiqun Cao,Hongzhi Ma,Hexun Huang
In order to overcome the shortcomings of insufficient red light component and poor thermal stability of commercial white light emitting diode (WLED), YAG:Ce, R (R: Gd 3+ , Pr 3+ , Gd 3+ and Pr 3+ ) fluorescent thin films were prepared by pulse laser deposition (PLD). The composition and microstructure, photoluminescence properties, and red-enhanced mechanism of co-doped YAG fluorescent thin films, as well as the electroluminescence behavior of the corresponding WLEDs were investigated. Results showed that the doping of Pr 3+ caused the emission spectrum energy of Ce 3+ to migrate, and an emission peak appeared at 606 nm in the red region. The doping of Gd 3+ caused the emission spectrum of Ce 3+ to shift to the red region, and the main peak position of the Ce 3+ emission spectrum is red-shifted from 523 nm to 548 nm. The YAG:Ce,Pr,Gd fluorescent film not only realized the improvement of red light components and red-shift, but also increased the energy transmission efficiency from 33.3% to 51.9%. Moreover, results of the color coordinate analysis also showed that the co-doping of Gd 3+ and Pr 3+ made the luminescence closer to the red region, reducing the color temperatures and hues changed to warm. Thus, tri-doped transparent fluorescent thin film were prospective for WLED application.
研究领域:
材料科学
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光学工程
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高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Yao Meng,Qiang-Qiang Zhu,Min-Hang Huang,Xiang-Yu Hu,Hong Zhang,Shuxing Li,Rong-Jun Xie,Le Wang
YAG:Ce 3+ PiG film cannot produce high color-rendering laser lighting due to the deficiency in red spectral component, but adding nitride-based red phosphors usually leads to dramatic decrease of brightness and efficiency as a result of their obvious luminance saturation. In this work, a sandwich structured PiG (SS-PiG) film was created using green-emitting YAGG:Ce 3+ and orange-emitting GdYAG:Ce 3+ phosphors, where two types of PiG films were separately co-fired on each surface of a sapphire substrate. The color-rendering index of SS-PiG film can reach 81.4 upon blue laser excitation, improved by 24.3% when compared with that of YAG:Ce 3+ PiG film (65.5). Driven by blue laser diodes with a flux density of 7.69 W mm -2 , the SS-PiG film shows a luminous emittance of 1362 lm mm -2 , which is 179% higher than traditional multilayer structured PiG film (489 lm mm -2 ). The SS-PiG film enables to enhance both of color rendition and luminance of laser-phosphor-converted lighting.
研究领域:
光学材料
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发光材料
·
激光技术
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2026
·Vol. 47
·期 4
·118965
·
IF 6.3
Liang Zhang,Haitao Zhang,Wentao Xu,Jiquan Huang,Youfu Zhou,Maochun Hong
YAG:Ce phosphor ceramics are important color converters for high-power LED lighting. Vat photopolymerization enables complex ceramic geometries, but mixed oxide systems require control of slurry stability, reactive densification, and structure-property relationships. YAG:Ce ceramics were fabricated by digital light processing (DLP) using reactive oxide precursors. A co-dispersant strategy produced a stable photocurable suspension with 51 vol% solid loading, supporting reliable printing. Optimized air calcination regulated precursor reaction and densification, giving vacuum-sintered ceramics with a dense microstructure, low porosity (0.03%), and high in-line transmittance (78.48% at 600 nm, 0.8 mm thickness). A hill-array ceramic was further fabricated. Compared with the flat counterpart of equivalent volume, the structured surface improved heat dissipation and light extraction, reducing peak temperature (by 37.5 °C at 90 W) and increasing luminous efficacy (from 172.02 to 185.54 lm/W at 50 W). These results indicate the potential of DLP-fabricated ceramics as color converters for high-power LED lighting applications.
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高影响因子
JOURNAL OF LUMINESCENCE
·
2023
·
IF 3.6
Lu Chen,Zhuangzhuang Ma,Jian Chen,Wang Guo
Laser-driven solid-state lighting has attracted much attention in recent years. However, the super-high luminous flux under high-power-density laser irradiation is accompanied by an enormous amount of heat. Here, to enhance the thermal robustness of phosphor converter materials, we prepared composite ceramics of YAG:Ce combined with high-thermal-conductivity MgO via simply vacuum sintering. 1.0 mol% MgF 2 was employed as the liquid-phase sintering additive to accelerate the densification process. The optimum temperature proves to be 1400 °C, at which MgO-YAG:Ce composites exhibit highly dense composite structure, without obvious reaction between MgO and YAG phases. Additionally, low sinterability of commercial YAG:Ce particles dragged down the densification process, which limits the YAG:Ce content of the composites. As a result, MgF 2 -doped MgO-10 vol% YAG:Ce composite ceramic (MYF10) sintered at 1400 °C exhibits the highest relative density of 99.33 % and thermal conductivity of 42.05 W/(m·K). Under 34.06 W/mm 2 blue laser excitation in a reflection mode, a stable laser-driven white light is obtained with the luminous flux of 2834 lm and luminous efficiency of 166 lm/W, respectively.
研究领域:
材料科学
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陶瓷
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光学材料
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固态照明
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热管理
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高影响因子
Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 37
·11449-11456
·
IF 6.641
Yirong Xu,Shuxing Li,Peng Zheng,Le Wang,Shihai You,Takashi Takeda,Naoto Hirosaki,Rong-Jun Xie
To achieve extra-high brightness laser lighting, the bottleneck of thermally-induced luminance saturation that phosphor materials (i.e., color converters) usually suffer from under high power density laser excitation must be broken. However, the mechanisms for thermal saturation are not fully understood yet. Here, thermal saturation of typical Ce3+-doped garnet phosphor ceramics was systematically investigated by considering the balance among heat generation, dissipation and resistance of color converters. With increasing Ce concentration (0.0167 → 0.433%), the thermal saturation threshold decreases due to more heat generation (i.e., 3.97 → 6.73 W at an incident laser power of 6.73 W). A tunable saturation threshold (2–49 W mm−2) was observed by a chemical substitution strategy because of the difference in the thermal resistance and heat generation. The sample thickness exerts a complex influence on the saturation threshold accompanied by increased heat generation and enhanced heat dissipation corroborated by a broader temperature distribution curve. Based on these investigations, a high-flux white light of 2347.9 lm is obtained with robust YAG:Ce ceramics irradiated with a high power density of 31.94 W mm−2. Moreover, a promising green color converter able to withstand a blue laser power density of 49 W mm−2 was discovered for laser displays with an output luminous flux of 3967.3 lm. This work provides a principle to design and/or select phosphor materials with high thermal saturation thresholds, thus accelerating the rapid development of laser-driven lighting and displays.
研究领域:
光学材料
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激光技术
·
材料科学
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2020
·
IF 4.495
Qiang-Qiang Zhu,Shuxing Li,Qiang Yuan,Hong Zhang,Le Wang
Yellow-emitting YAG:Ce transparent ceramic is recognized as an ideal color converter in high-power blue LEDs and LDs , but the absence of scattering centers in its microstructure leads to a low light extraction efficiency and poor light uniformity. Here, taking advantage of the scattering effect and the transparency of YAG:Ce ceramics, Ce-free YAG phase was used as a second component to form a composite with YAG:Ce phosphor. The sintered YAG:Ce-YAG ceramic possessed a high transparency of ∼63 % and a thermal conductivity of 8.9 Wm −1 K −1 . Due to its beneficial thermal properties and high external quantum efficiency of 70.2 %, the YAG:Ce-YAG ceramic could be excited under a high blue-laser flux density of up to 9.60 W/mm 2 and showed a luminous emittance of 1220 lm/mm 2 . Due to light scattering arising from the slightly different refractive indices of the two phases, the designed YAG:Ce-YAG ceramic showed better lighting effects than a single-phase transparent YAG:Ce ceramic.
研究领域:
材料科学
·
光电子学
·
光子学
·
陶瓷工程
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高影响因子
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