CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Zhi Zhou,Haifeng Zhu,Xu Huang,Yalan She,Yuan Zhong,Jing Wang,Min Liu,Wei Li,Mao Xia
Highly efficient cyan/green phosphors are identified as functional block to fulfill the cyan gap in emissive spectra of traditional white light emitting diodes (w-LEDs). Herein, a series of emission-tunable solid solution phosphors, namely KAl 11-x Ga x O 17 :Mn 2+ (x = 0–11), with superior luminescence properties and anti-thermal-quenching behavior is reported. KAl 11 O 17 :Mn 2+ dedicates green emission at 510 nm with a narrow full width at half maximum of 23.5 nm, and excellent thermal quenching resistance (130.4% at 150 °C) due to the thermal induced electron detrapping. Interestingly, doping Ga 3+ ions into this hexaaluminate matrix enables harvested phosphor with enhanced emission by 2.35 times, and achieves luminescence tuning from green to cyan. Moreover, such a Ga 3+ substituting could stabilize the luminescence (nearly zero-thermal-quenching) of phosphor even at the elevated temperature range of 25–250 °C. Based on the thermoluminescence (TL) analysis and density functional theory (DFT) calculations, this extraordinary phenomenon was reasonably assigned to the enhancement of photoionization effect and the detrapping of the captured electrons from shallow trap state. The w-LEDs fabricated by employing KAl 11-x Ga x O 17 :Mn 2+ as cyan/green emitting component show superior color rendering index (improved from 85.5 to 96.3), indicating these Mn 2+ -doped hexaaluminate phosphors may be candidates used for high-power w-LEDs in the future. This work opens up a new pathway to construct anti-thermal-quenching and spectra-tunable phosphors for optical 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
ACS Applied Electronic Materials
·
2021
·
IF 3.314
Wasim Ullah Khan,Waheed Ullah Khan,Hao Lin,Zhiyuan Cheng,Muhammad Wajid Shah,Yueli Zhang
The important objectives that have been usually ignored regarding the development of white-light-emitting diodes (WLEDs) are the stability, red spectral region deficiency, high correlated color temperature (CCT), and low color-rending index (CRI) that restrict their effectiveness for practical implementation. Herein, we used systematic screening of multi-doped Ca3LuAl3B4O15 (CLAB) samples to evaluate singly and doubly doped down-converting phosphors that exhibit tuning emission and spectrally pure red emission with high color purity at the ultraviolet light excitation and enhanced thermal stability. A comprehensive kinetic model of the energy transfer (ET) mechanism was developed and validated with the extensive experimental data set. Applying this model, we elucidated the ET mechanisms producing a spectrally pure red emission via dipole–dipole interaction. Moreover, CL0.8AB:0.1Ce3+,0.1Sm3+ revealed excellent chemical stability under 80% relative humidity and 80 °C severe thermal conditions. Interestingly, when the temperature was increased from 300 to 425 K, the intensity of Ce3+ emission was reduced with the production of certain Sm3+ emissions via ET. The WLED containing CL0.8AB:0.1Ce3+,0.1Sm3+ and Sr2SiO4:Eu2+ demonstrated warm white light with a high CRI of 89.8–85.7 and a low CCT equal to 4393–4482 K. These parameters are comparable to that of the commercially available YAG:Ce3+ phosphor combined with a blue LED chip (CCT ≈ 7746 K and CRI ≈ 75).
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
Small
·
2025
·
IF 12.1
Qianqian Wang,Haibo Li,Hua Tong,Jialin Zhu,Jiali Fan,Shifeng Pan,Zhennan Zhou,Wei Liu,Gangfeng Ouyang
The development of single-component white-light emissive phosphors has become a key research area in white light-emitting diode (WLED) technology. However, achieving real color reproduction with an ultrahigh color rendering index (CRI) remains challenging. Herein, a series of 0D hybrid copper halides (TEA) 2 Cu 2 Br 4- x Cl x (TEA = tetraethylammonium, x = 0–4) crystals are designed and prepared by a facile solvothermal method. By controlling the composition ratio of Cl − and Br − , the emission spectra are tunable in visible light region from blue to yellow, and a single-component crystal (TEA) 2 Cu 2 Br 2 Cl 2 with broadband white-light emission and ultrahigh CRI is obtained. Detailed studies on photophysical mechanism demonstrate that the unique 0D structure of (TEA) 2 Cu 2 Br 2 Cl 2 can produce effective emission of self-trapped excitons (STEs), and its dual-band emission phenomenon stems from two STE states in the [Cu 2 Br 2 Cl 2 ] 2− dimer. Moreover, the CIE coordinates of (TEA) 2 Cu 2 Br 2 Cl 2 (0.32, 0.33) are approximated to pure white light (0.33, 0.33), making it an ideal choice for natural WLED applications. A WLED device is fabricated by coating this emitter on a 310 nm UV chip, achieving an ultrahigh CRI of Ra = 95 and R9 = 90. This work provides new design principles for developing eco-friendly white-emission phosphors for single-component solid-state 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
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Halizati Abulimiti,Reziwanguli Yantake,Aierpati Taximaimaiti,Taximaiti Yusufu,Aierken Sidike
Currently, there is a cyan gap in white light-emitting diodes (LEDs) manufactured by combining near-ultraviolet (NUV) chips with tricolour (blue/green/red) phosphors, resulting in a poor colour rendering index (Ra). Broadband blue-cyan phosphors contain blue, cyan and green luminescent components that complement the cyan gap. In this paper, feldspar-structured Ba 0.92- x Sr x Al 2 Si 2 O 8 :0.08Eu 2+ ( x = 0–0.5) phosphors were prepared by a high-temperature solid-phase method and a cation substitution strategy. A phase transition was achieved by varying the concentration of x , which resulted in the formation of two luminescent centres and a 10.33-fold enhancement of the luminescence intensity for Ba 0.92 Al 2 Si 2 O 8 :0.08Eu 2+ . The colour of the emission changed from the original green to blue-cyan, and the strongest emission peak with a half-height width of 94.5 nm was observed at a Sr 2+ concentration of 0.3 (30%) and covered the blue, cyan and green wavelength ranges (390–600 nm). The experimental value of the optical band of the substrate is 5.71 eV, and the luminous intensity of the Ba 0.62 Sr 0.3 Al 2 Si 2 O 8 :0.08Eu 2+ sample at 150 °C was 91.3% of that at room temperature. Ba 0.62 Sr 0.3 Al 2 Si 2 O 8 :0.08Eu 2+ , (Ca, Sr) AlSiN 3 :Eu 2+ and 365 nm NUV chips were successfully packaged into white LED devices. The colour rendering index (Ra) of the prepared white LED devices was 87, R9 was 89, the colour coordinates were (0.3763, 0.3382), and the colour temperature was 3759 K, which effectively solves the problem of the lack of cyan luminescent components in white LED devices and simplifies the manufacturing process of white LEDs.
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
Journal of Materials Chemistry C
·
2019
·Vol. 8
·期 4
·1286-1291
·
IF 6.641
Xiaoxi Li,Zifei Wang,Yang Liu,Weiguang Zhang,Chaofeng Zhu,Xiangeng Meng
Fluorescent carbon dots (CDs) have emerged as promising materials for white light-emitting diodes (WLEDs) on account of carbon's intrinsic merits of high stability, low cost, and environment-friendliness. However, CDs usually give relatively narrow emission with full width at half maximum within 70–90 nm, which fundamentally restrains construction of CDs-based WLEDs with high color rendering index (CRI). Here, we demonstrate tricolor ultrabroad-band (109–120 nm) emissive CDs (Tri-CDs) with a quantum yield (QY) up to 21–64% by a one-pot solvothermal route. Experimental investigations reveal that tunable emissions of these CDs are based on differently sized sp2 conjugated domains and the content of graphitic nitrogen, which can be modulated by controlling the carbonization and deamination processes during solvothermal reactions. The ultrabroad-band emission spectra of Tri-CDs originate from broad distribution of the particle size. A WLED with Commission Internationale de l’Eclairage (CIE) color coordinate of (0.362, 0.370) and high CRI of 96.5 is fabricated by integrating Tri-CDs films with an ultraviolet LED chip. This work opens up a new opportunity for the development of high CRI CDs-based WLEDs.
研究领域:
材料科学
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光学工程
✓ 已验证
DOI
高影响因子
Materials Today Chemistry
·
2025
·
IF 6.7
Zeyu Wang,Qing Yao,Jindou Shi,Zheyuan Da,Junnan Wang,Ahmed Allam,Haifa E. Alfassam,Xiangming Li,Jinyou Shao,Minqiang Wang
Multicolor solid-state carbon dots (MSCDs) with superior photothermal stability and tunable fluorescence exhibit significant potential for applications in light-emitting diodes (LEDs) and optoelectronic devices. However, the development of a facile and efficient synthetic method using simple raw materials remains a challenge. In this study, blue (B), green (G), and red (R) emissive carbon dots (B-CDs, G-CDs, and R-CDs) are synthesized by varying pre-treatment methods and raw material ratios, using 1-(1-Naphthyl)ethylamine (1-NEA) as the carbon source and boric acid (BA) as the matrix. B-CDs, prepared via freeze-drying pre-treatment in a nitrogen (N 2 ) protective atmosphere, exhibits the smallest particle size and the largest emission bandgap. Conversely, G-CDs and R-CDs display larger particle sizes, with R-CDs having the smallest emission bandgap due to differing raw material ratios that introduced distinct surface state defects. These variations in emission bandgaps result in diverse fluorescence emissions under ultraviolet (UV) light excitation. Leveraging the excellent luminescent properties, white LEDs (W-LEDs) are fabricated by combining and coating the CDs onto a 400 nm LED chip. The resulting W-LEDs demonstrate outstanding photothermal stability and a high color rendering index (CRI) of 90–93 during prolonged operation. This work provides valuable insights for the application of MSCDs in W-LED technology.
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
JOURNAL OF ALLOYS AND COMPOUNDS
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2025
·
IF 6.3
Yan Wang,Jianwei Dao,Zhihao Jiang,Zihao Han,Liang Yang,Tiqun Wei,An Xie,Zhicheng Lv
Efficient green phosphors with high internal quantum efficiency (IQE) are crucial for developing high color rendering white light-emitting diodes (LEDs). Herein, through co-substituting cation sites, Y 3+ /Al 3+ are replaced by Ba 2+ /Si 4+ respectively in the Y 3 Al 5 O 12 (YAG) lattice, yielding novel Ce 3+ -doped BaY 2 Al 4 SiO 12 (BYAS) green phosphors with symmetrical and stable structure similar to that of YAG. Notably, the BY 1.94 AS:0.06Ce 3+ phosphor exhibits exceptional IQE of 96.4%. Upon adjusting the Ce 3+ doping concentration, the optimal BY 1.94 AS:0.06Ce 3+ phosphor shows green emission at 533 nm and a broad full width at half maximum of 87 nm under 469 nm excitation. The emission spectrum ranges from 500 to 700 nm, primarily due to the characteristic 5d to 4 f transitions of Ce 3+ ions. The BY 1.94 AS:0.06Ce 3+ phosphor retains 67.7% of its initial intensity at 423 K (E a = 0.241 eV), demonstrating high thermal stability. As-prepared BY 1.94 AS:0.06Ce 3+ green phosphor and commercial CaAlSiN 3 :Eu 2+ red phosphors were combined with InGaN blue chip to fabricate a white LEDs device. The device exhibits warm white light with a high color rendering index (Ra = 85.9, R9 = 41.1), a low correlated color temperature (5064 K) and an excellent luminous efficiency (80.24 lm/W). This work suggests that the novel high-efficiency BYAS:Ce 3+ green phosphors possess significant potential for achieving high color rendering in warm-white LEDs.
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
OPTICS AND LASER TECHNOLOGY
·
2019
·
IF 3.319
Qi Yao,Hongbing Wang,Yunzhuo Wang,Lintao Zhang,Wanlu Zhang,Yi Zhang
In this work, we synthesized a sun-like light source with tri-chromatic broad spectra, composed of light source units with single-peak 435-nm carbon quantum dots (QDs) and 695-nm perovskite QDs, and dual-peak 510- and 590-nm Ag-doped InP QDs, referencing CIE standard illuminants D50 and D65. Based on a spectral angle measure approach, we adopt the spectral similarity index (SSI) to measure the similarity between the synthesized light source and reference light source. We quantify the colour rendering and SSI of the tri-chromatic light source units and obtain the colour rendering and SSI as a function of chromaticity coordinate. The synthesized light source reaches an ideal performance with a maximum spectral similarity of 0.98 and colour rendering of about 93. This work is the first to synthesize a full-spectrum sun-like source with three QD light units, including a dual-peak QD unit, and proves QD LEDs as promising light sources for synthesizing full-spectrum light sources. In the future, improving the long wavelength part (>700 nm) of the broad-spectrum QD LED unit may significantly improve the colour rendering property.
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
Nature Communications
·
2025
·Vol. 16
·期 1
·1-11
·
IF 15.7
Chen Jiawei,Ji Kangyu,Dai Linjie,Xiang Hengyang,Yu Zhongzheng,Iqbal Affan N.,Wang Jian,Ma Xingyue,Guo Renjun,Anaya Miguel,Song Xiufeng,Lu Yang,Chiang Yu-Hsien,Li Weijin,Shen Yalong,Luo Xiyu,Mirabelli Alessandro,Cheng Yuanzhuang,Chen Xinrui,Ma Dongxin,Fan Zhiyong,Yang Yurong,Duan Lian,Stranks Samuel D.,Zeng Haibo
Traditional white light-emitting diodes operate by exciting phosphors using blue light-emitting diodes, leading to the absence of specific colour bands compared with the visible light region of the sunlight spectrum (400–780 nm), and excess blue light increases the risk of harmful effects on ecosystems and organisms. Here, we precisely design and regulate heterophase γ / δ -CsPb(I/Cl) 3 at the nanoscale for uniform heterophase distribution, balanced flow of charges and tunable spectrum. Then, γ / δ -CsPb(I/Cl) 3 directly excited by electricity shows full-spectrum white electroluminescence covering 400–780 nm with standard Commission Internationale de l’Eclairage coordinates of (0.33, 0.33), a Colour Rendering Index of 95, a Correlated Colour Temperature of 5829 K and a Delta u,v of −3 × 10 −4 , accompanied with balanced white light composition (Melanopic ratio = 1.004). The match indices of such five core indicators to standard sunlight reach 100%, 95% (97% for R 9 ), 99.5%, 99.97% and 99.6%, respectively, far ahead of as-fabricated commercial white light-emitting diodes.
研究领域:
材料科学
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光学工程
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纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ChemPlusChem
·
2018
·Vol. 83
·期 11
·1052-1056
·
IF 3.205
Wenxu Yin,Xiaoyu Zhang,Xue Bai,Dingke Xue,Xingwei Zhuang,Hongwei Song,William W. Yu
Graphical S-TOP and go ! A low-cost, one-pot synthesis of WS 2 quantum dots was devised that relies on activated elemental sulfur (S-TOP, S dissolved in tri-n-octylphosphine) instead of an organic sulfur source. Light-emitting devices prepared from this material display a high color rendering index of 93 (see figure). We report a facile and low-cost synthesis of WS 2 quantum dots with bright broad-band emission, which are suitable for lighting applications. The thus fabricated WS 2 light-emitting diodes (LEDs) exhibit voltage independent electroluminescence spectra, and the optimized white LEDs generate a high color rendering index of 93.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
Materials Today Chemistry
·
2024
·
IF 6.7
Jingming Chan,Balaji Devakumar,Huanzhuo Gao,Xiaoyong Huang
High-color-rendering full-spectrum warm-white light-emitting diodes (LEDs) are in great demand in the field of high-end solid-state white lighting. However, the so-called cyan gap (480–520 nm) in conventional white LEDs always limits their color rendering index (CRI) values, and thus there is a pressing need for cyan phosphors to fabricate full-spectrum white LEDs. Herein, we report on an efficient violet-excited blue-cyan-emitting Ca 2 YHf 2 GaAl 2 O 12 :Ce 3+ (CYHGA:Ce 3+ ) garnet phosphor, which is capable of realizing full-spectrum warm-white LEDs with superior CRI (Ra = 98.2, R12 = 96, R9 = 95) and low correlated color temperature (CCT) of 3735 K. Importantly, when excited at 398 nm, the optimal CYHGA:2%Ce 3+ sample exhibits a strong broadband blue-cyan emission (emission peak: 473 nm; emission bandwidth: 92 nm) with high luminescence efficiency (internal quantum efficiency: 69.9 %; external quantum efficiency: 43.3 %), which perfectly covers both blue and cyan spectral region and enables to close the so-called cyan gap. The fabricated warm-white LED device based on CYHGA:2%Ce 3+ blue-cyan phosphor generates bright warm-white lights with ultra-high CRI values (Ra ≥96.5; R12 ≥ 94; R9 ≥ 93) and low CCT values (3674–3845 K) upon 20–320 mA driving currents. Thus, blue-cyan-emitting CYHGA:Ce 3+ garnet phosphors possess a bright application prospect in high-quality full-spectrum LED lighting.
研究领域:
材料科学
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光学工程
·
固态照明
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2022
·
IF 10.319
Zhe Hu,Hanxu Lu,Wenjie Zhou,Jinxin Wei,Hanqing Dai,Hong Liu,Zhiyong Xiong,Fengxian Xie,Wanlu Zhang,Ruiqian Guo
Over the past few decades, I-III-VI quantum dots (QDs) have attracted considerable attention due to their large Stokes shifts, good eco-friendliness, and wide tunable emissions. In this work, a facile microwave-assisted aqueous route using glutathione (GSH) and citric acid (CA) as dual stabilizers is introduced to synthesize AgInGaS/ZnS (AIGS/ZnS) core/shell QDs. An exceptional photoluminescence quantum yield (PL QY) as high as 79% is successfully achieved, boosting the best performance of water-dispersible AIGS QDs. By varying the Ag/Ga ratio, the PL peak wavelength can be tuned from 547 to 616 nm, and luminescent hydrogel films with different colors are obtained by embedding AIGS/ZnS QDs in polyacrylamide/poly-vinyl alcohol (PAAm/PVA) hydrogels. The white light-emitting diode (WLED) with a high color rendering index (CRI) of 92.1 ( R 9 =92.0) and a correlated color temperature (CCT) of 3022 K is fabricated using QDs-PAAm/PVA hydrogel films in combination with a blue InGaN LED chip, indicating that the as-prepared QDs are competitive color-conversion materials for WLEDs.
研究领域:
材料科学
·
光学工程
·
纳米技术
✓ 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）