CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Jianwei Dao,Zihao Han,Zhihao Jiang,Tiqun Wei,Junlin Xue,Bin Wang,Sicheng Yi,Liang Yang
Narrow-band red phosphors excited by near-ultraviolet light (n-UV) are significant for enhancing the R9 index and can produce high color rendering white LEDs. A range of KSr 1-x-y Ca y PO 4 :xEu 3+ red phosphors were synthesized by high-temperature solid-state reaction method. We investigated the effects of partially substituting Sr 2+ ions with Ca 2+ ions on the phosphors' crystal structure, photoluminescence and thermal stability. Significantly, incorporating Ca 2+ ions enhances the luminescent properties and thermal stability. Under n-UV light excitation, all samples exhibit red emission around 614 nm, corresponding to the 5 D 0 → 7 F 2 transition of Eu 3+ ions. At the doping concentration of Eu 3+ ions (x = 0.08), an optimal KSr 0.52 Ca 0.4 PO 4 :0.08Eu 3+ (y = 0.4) sample was obtained. The excitation wavelength exhibited a slight violet shift from 398 nm to 396 nm. At 150 °C, the luminescence intensity of KSr 0.92 PO 4 :0.08Eu 3+ remains 80.1 % of its value at room temperature, while that of KSr 0.52 Ca 0.4 PO 4 :0.08Eu 3+ reaches 89.7 %. White LED device can be fabricated by combining the as-prepared KSr 0.52 Ca 0.4 PO 4 :0.08Eu 3+ red phosphor with commercial BaMgAl 10 O 17 :Eu 2+ blue and (Ba, Sr) 2 SiO 4 :Eu 2+ green phosphors, along with encapsulation using n-UV LED chip (395–400 nm). The device emits bright white light and exhibits a high color rendering index (Ra = 87.6, R9 = 89.8) and suitable correlated color temperature (CCT = 5523 K) at 300 mA drive current. The results demonstrate that this work provides new application prospects for the fabrication of high color rendering white LEDs using n-UV light.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Advanced Optical Materials
·
2025
·
IF 7.2
Moushira. A. Mohamed,Mohamed. A. Ali,Shaorun Guo,Xiaofeng Liu,Shengzhi Sun,Jianrong Qiu
The encapsulation of phosphor particles into a silica glass (PiSG) matrix leads to the formation of an efficient and chemically durable spectral converter, which is a promising candidate for the fabrication of stable and high-power phosphor-converted white light-emitting-diodes (pc-wLEDs). Here, high-throughput fabrication of transparent PiSG spectral converters based on Y 3 Al 5 O 12 :Ce 3+ , Mg 2 Al 4 Si 5 O 18 :Eu 2+ , and Y 3 Al 5 O 12 :Cr 3+ is demonstrated via injection molding followed by pressureless sintering. The as-fabricated PiSG exhibits broadband emission covering the visible and near-infrared (vis-NIR) spectral regions (i.e., 500–900 nm) with a high-luminescence efficiency (> 85%) and high-chemical and thermal stabilities, retaining more than 90% of its emission intensity at 200 °C. Consequently, high-power pc-vis-NIR-LEDs (10 W) are manufactured using the injection molded PiSG spectral converters, which showed excellent luminescence performance (i.e., luminous efficiency (LE) = 115 Im W −1 , correlated-color-temperature (CCT) = 4531 K, and color-rendering-index (R a ) = 90.1 at 50 mA and input power of 0.45 W). This work enables the fabrication of stable and high-power broadband LEDs with a low cost and outstanding optical properties, making the as-fabricated pc-vis-NIR-LEDs based on PiSG spectral-converter a favorable device for lighting and bioimaging applications.
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
ELECTROCHIMICA ACTA
·
2023
·
IF 6.6
Yabing Sun,Haoju Li,Xin Zhou,Yonggang Min,Yannan Qian
It is well known that the balanced charge injection helps prepare high-performance red light-emitting diodes (LEDs) in the electroactive material CsPbBr x I 3- x quantum dots (QDs). Employing a hydrothermal method, we synthesized MoO 2 nanocrystals and doped them into Poly(3,4-ethylenedioxythiophene) /poly(styrenesulfonate) (PEDOT:PSS). The results show that the synthesized MoO 2 nanocrystals can modulate the work function of PEDOT:PSS and enhance the conductivity of the PEDOT:PSS films, which is attributed to disrupting the hydrogen bond between PEDOT and PSS, and inducing the transition of PEDOT from benzoid to quinoid structure. In the PEDOT:PSS- x MoO 2 film, the work function increases from 4.9 eV to 5.09 eV when the content of x is 15%, which reduces the energy barrier between the PEDOT:PSS- x MoO 2 and the hole transport layer: poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzi (poly-TPD), thus promoting the hole transport and improving the V on of the devices. Additionally, the device's external quantum efficiency (EQE) reaches a maximum value of 7.53% at x = 15% enabling an improvement of 2.6 times over the base device (EQE=2.10%). This work proves that PEDOT:PSS- x MoO 2 as a hole transport layer is an effective material for preparing high-performance QD-LEDs.
研究领域:
材料科学
·
光电技术
✓ 已验证
DOI
高影响因子
JAPANESE JOURNAL OF APPLIED PHYSICS
·
2022
·Vol. 61
·期 6
·062002
·
IF 1.491
Lei Wang,Subiyinuer Jilili,Ayinuremu Tuerxun,Aierken Sidike,Qingling Wang
A series of Tb3+, Eu3+, Li+ co-doped SrSiO3 phosphors were prepared using the high-temperature solid-phase method. The X-ray diffraction results showed that Tb3+ and Eu3+ successfully entered into the SrSiO3 matrix lattice. Strong energy transfer from Tb3+ to Eu3+ is exhibited with a calculated energy transfer efficiency of 94.7%. Doping of the charge compensator Li+ increased the luminescence intensity of the SrSiO3:6%Tb3+, 6%Eu3+, 3%Li+ phosphor at a wavelength of 614 nm by 4.2 times and significantly improved the color purity of this phosphor (Cp = 85.9%). Based on color coordinate analysis, the phosphor color coordinates are located near (0.615, 0.365), which belongs to the red region. The phosphor was integrated into a white LED. The resultant package exhibited a color temperature of 6479 K and a color rendering index of 93.8. Its luminous performance was also very stable under different drive currents.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Lei Fu,Di Wu,Yanfei Xiao,Wanfang Zou,Jinfen Kuang,Yan Liang,Fu Du,Jiaqing Peng,Xinyu Ye
Blue phosphor Sr 5−x-y R y (PO 4 ) 3 Cl:xEu 2+ (R = La, Gd, Lu) was prepared via solid-state reaction process, in which R 3+ replaces part of Sr 2+ ions in the matrix to benefit Eu 2+ luminescence. The change of Eu 2+ /Eu 3+ values were studied by XPS , and the results shown that the incorporation of R 3+ in the matrix resulted in the values increase of Eu 2+ /Eu 3+ . And substitute R 3+ non-equivalently for Sr 2+ , the modified Sr 5−x-y R y (PO 4 ) 3 Cl:xEu 2+ phosphors show better luminescence intensity and thermal stability. The emission intensity of Sr 4.72 Lu 0.2 (PO 4 ) 3 Cl:0.08Eu 2+ is 1.97 times of Sr 4.95 (PO 4 ) 3 Cl:0.05Eu 2+ . Moreover, the thermal quenching of Eu 2+ photoluminescence could be reduced. Compared to the commercial BAM:Eu 2+ phosphor, the stabilities of all Sr 4.72 R 0.2 (PO 4 ) 3 Cl:0.08Eu 2+ (R=La 3+ , Gd 3+ and Lu 3+ ) phosphors are better than that of BAM:Eu 2+ at the temperatures below 100 °C. The luminescent intensity of Sr 4.72 Lu 0.2 (PO 4 ) 3 Cl:0.08Eu 2+ maintains 95% while BAM:Eu 2+ is only 88% of the initial intensity at 150 °C. By combining Sr 4.72 Lu 0.2 (PO 4 ) 3 Cl:0.08Eu 2+ , Y 3 (Al,Ga) 5 O 12 :Ce 3+ and CaAlSiN 3 :Eu 2+ with 400 nm near-ultraviolet LED chip, a white-light-emitting diode was obtained. The fabricated WLED device with CIE color coordinates x = 0.3896, y = 0.3788, low CCT (3775 K) and high Ra (95.1), has enormous potential application in full-spectrum lighting field.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2022
·
IF 4.171
Zijing Zhou,Anlin Zhang,Li Zhou,Ziyue Hu,Yixuan Zhao,Jiexin Chen,Yanyan Li,Lei Zhao,Bin Deng,Ruijin Yu
In the present work, a series of zincate CaY 2 Sb 2 (ZnO 4 ) 3 :Eu 3+ phosphors were successfully obtained via the conventional solid-state method at high temperature. The phase purity, morphology, element mapping, photoluminescence excitation/emission (PLE/PL), and decay time of the obtained phosphors were investigated systematically. Results show that the synthesized samples demonstrate the strongest red-emitting peak at 610 nm under the n-ultraviolet (n-UV) 395 nm excitation. The Judd-Ofelt parameters (Ω 2 , Ω 4 ), radiative transition rates, and branching ratios ( β 0 J, J = 2, 4) of CaY 2 Sb 2 (ZnO 4 ) 3 :Eu 3+ to explore the Eu 3+ -coordinated environment in the host matrix. The concentration quenching of CaY 2 Sb 2 (ZnO 4 ) 3 :2 x Eu 3+ phosphors happened until at high doping concentration of x = 50 mol%. CaY 2 Sb 2 (ZnO 4 ) 3 :100 mol%Eu 3+ sample presented the excellent thermal stability with abnormal thermal quenching behavior. Compared with the commercial Y 2 O 3 :Eu 3+ red phosphor , the luminescent intensity of the prepared phosphor is 1.14 times stronger. The high internal quantum efficiency (IQE) of CaY 2 Sb 2 (ZnO 4 ) 3 :100 mol%Eu 3+ phosphor is 79.20%. In addition, the fabricated red and white light-emitting diodes (w-LEDs) both emit bright light. The w-LED demonstrates a high color rendering index ( R a = 96) and a low correlated color temperature (CCT = 5249 K). Therefore, the prepared red-emitting phosphor has a promising application in w-LEDs.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
INORGANICA CHIMICA ACTA
·
2021
·
IF 2.545
Tian-Cheng Wu,Qiao-Long Hu,Ting-Hong Huang,Yi-Shun Cui,Dan Zheng,Changyan Ji,Cheng Luo
A series of copper(I) - diimine complexes, [Cu(bdpp)(bpy)]BF 4 ( 1 ), [Cu(bdpp) (pen)]BF 4 ( 2 ), [Cu(bdpp)(damp)]BF 4 ( 3 ), [Cu(bdpp)(pen)]BF 4 ( 4 ) (bdpp = 4,6-bis-(biphenyl phosphino) phenoxazine, bpy = 2,2′-bipyridine, phen = 1,10-Phenanthroline, dmp = 2,9-dimethyl-1,10-phenanthroline, bphen = 4,7-diphenyl-1,10-phenanthroline), have been synthesized and characterized by IR, 1 H NMR, 31 P NMR, XRD and X-ray crystal structure analysis. Structural analysis reveals that each Cu + in 1 – 4 is four-coordinated by two N atoms and two P atoms and adopts a distorted tetrahedral geometry. DFT calculations show that the HOMOs in 1 – 4 are mainly comprised of bdpp and copper d–orbitals, while the LUMOs are mainly dominated by diimine ligands. Calculation of atomic charges indicates that the charges of the central Cu atoms in 1 – 4 are less than + 1, and the diimine ligands may be the key to the metal charge transfer to the coordinated atom. In 1 – 4 , the maximum phosphorescent lifetimes and quantum yields are up to 349 μs and 22%, respectively. Moreover, complex 3 is used for fabricating the LED device, showing a decent performance with the maximum EQE of 11%.
研究领域:
化学
·
材料科学
✓ 已验证
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
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Yuhang Kuang,Jiance Jin,Gaochao Liu,Weibin Chen,Zhiguo Xia
Single-phase white-light emitters in the lighting technology overcome the challenges of re-absorption and color shift. However, achieving the broadband white emission in single-phase phosphor remains a challenge. Here, crystallized KBaScSi 3 O 9 :Eu 2+ (KBSSO:Eu 2+ ) glass-ceramics (GC) with abundant cationic sites have been developed and an ultra-broad emission band ranging from 460 to 800 nm have been found, in which the asymmetric green emission is ascribed to the Eu 2+ ions in [KO 8 ] and [BaO 7 ] polyhedra, while the red emission centered at 620 nm is originated from Eu 2+ ions in [ScO 6 ] sites. The optimized GC-converted white LED (WLED) exhibits a high color rendering index ( R a = 89.8) and low correlated color temperature (CCT = 4241 K). Moreover, the encapsulant-free GCc-WLED can operate continuously under high drive currents. This work paves the way for the design and future development of single-phase high-power white light sources.
研究领域:
材料科学
·
光学工程
·
照明技术
✓ 已验证
产品关联
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2024
·
IF 3.2
Pengju Xia,Yifeng Lei,Wanyuan Li,Kaiting Wu,Chengyu Ni,Man Xu,Wubin Dai
With the growing public awareness of protecting vision and prevention of hazardous effects, there is much-needed research on a “healthy” full visible spectrum under near-ultraviolet (nUV) excitation in phosphor-converted white light-emitting diodes (pc-wLEDs) to fill the “cyan gap” and avoid employing a blue LED chip. Herein, a novel series of borosilicates Ba2CaB2Si4O14 (BCBS): Ce3+/Tb3+/Sm3+/Sr2+/Na+ phosphors, presenting color-tunable photoluminescence (PL), high quantum yield (QY), and thermal stability, were designed and synthesized via a facile solid-phase reaction. The Rietveld analyses, density functional theory (DFT) simulations, and theoretical calculations of bond energy together imply the site occupations of Ce/Tb/Sm on Ba2+/Ca2+ sites with a preferred location on Ca2+ over the Ba2+ site. The broad/bright cyan-PL from BCBS: Ce under nUV excitation is associated with the allowed f–d transitions of Ce3+ and dual-site occupancies. The forbidden f–f transitions of both the green-PL of Tb and the red-PL of Sm were insensitive to the site environment and helpful to PL color regulation. The cascading Ce → Tb → Sm energy transfer is confirmed, where Tb is regarded as an energy transfer (ET) bridge to avoid the metal–metal charge transfer (MMCT) effect. The introduction of Na+ as both flux and charge compensator is for the sake of decreasing defects from heterovalent substitutions and regulating morphology. Further incorporation of Sr2+ is to modulate the lattice environments of dopants for controlling the shift of PL. Finally, as a proof-of-concept implement, a pc-wLED assembled by BCBS: Ce/Tb/Sm/Sr/Na and an nUV LED chip via a remote “capping” packaging strategy show attractive performance.
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
Advanced Optical Materials
·
2024
·Vol. 12
·期 22
·2400722
·
IF 8
Zhen-Yu Ma,Bai-Sheng Zhu,Xue-Chen Ru,Yi-Chen Yin,Li-Zhe Feng,Guan-Jie Ding,Mei-Yu Zhou,Yong-Hui Song,Hong-Min Zhou,Cheng-Ming Wang,Jing-Ming Hao,Hong-Bin Yao
Inorganic CsPbI 3 perovskite has great potential to fabricate deep-red light-emitting diodes (LEDs) owing to excellent color purity, thermal stability, and carrier mobility. However, fabricating high-quality CsPbI 3 thin films for high-performance LEDs remains challenging. While it is demonstrated that hydrogen bonds between organic ammonium cations and molecule additives can lead to high-quality organic–inorganic hybrid perovskite films, this method cannot be applied to CsPbI 3 thin films due to the absence of hydrogen bonds between Cs + ions and additives. In this study, an amorphous complex-seed-crystal growth process to fabricate high-quality γ -CsPbI 3 cuboid crystallite thin films, is reported. During the initial annealing, the metastable intermediates formed crystal nucleate seeds and transformed into amorphous complex intermediates, maintaining stability at an elevated temperature for perovskite crystallization. With prolonged annealing, the amorphous complex around the nucleate seeds gradually converts to γ -CsPbI 3 perovskite, enabling us to fabricate CsPbI 3 thin films with high crystallinity and orientation. The resulting deep-red LEDs exhibit a peak external quantum efficiency (EQE) of 16.5% and a high maximum luminance of 3158 cd m −2 . Moreover, the devices show significantly suppressed efficiency roll-off, maintaining an EQE of 14.8% even under a high current density of 500 mA cm −2 .
研究领域:
材料科学
·
光电技术
✓ 已验证
产品关联
DOI
高影响因子
Advanced Optical Materials
·
2024
·
IF 8
Noor Zamin Khan,Sayed Ali Khan,Nisar Muhammad,Weilong Chen,Jahangeer Ahmed,Muhammad Amin Padhiar,Mei Chen,Marcin Runowski,Saad M. Alshehri,Baohua Zhang,Shu-Sheng Pan,Ren-Kui Zheng
Sr 3 CaNb 2 O 9 :Dy 3+ /Eu 3+ phosphors with a complex perovskite structure are prepared using a high-temperature solid- state reaction technique. These phosphors are doped either singly or in combination with Dy 3+ /Eu 3+ ions, resulting in efficient energy transfer from Dy 3+ to Eu 3+ and thus tunable-color emission. Under 353 nm excitation, the Sr 3 CaNb 2 O 9 :Dy 3+ phosphor emits blue (492 nm), yellow (583 nm), and red (682 nm) light, with the optimal doping concentration of Dy 3+ of 0.04%. When excited by 394 nm ( 7 F 0 → 5 L 6 ), the Sr 3 CaNb 2 O 9 :Eu 3+ phosphor exhibits two most intense emissions centered at 593 nm ( 5 D 0 → 7 F 1 ) and 614 nm ( 5 D 0 → 7 F 2 ). The decrease in luminescence intensity with increasing doping concentration of Dy 3+ and Eu 3+ is due to the cross-relaxation associated with electric dipole–dipole interaction. Photoluminescence emission measurements under excitations of 353 and 365 nm indicate that the Sr 3 CaNb 2 O 9 :0.04Dy 3+ /0.05Eu 3+ phosphor shows excellent thermal stability, even at a temperature of 150 °C, where the luminescence intensity preserves 79% of its initial value at room temperature. The electroluminescence performance of the Sr 3 CaNb 2 O 9 :0.04Dy 3+ /0.05Eu 3+ phosphor is tested with 365 nm LED chips for potential use in white LEDs. The results confirm that Sr 3 CaNb 2 O 9 :0.04Dy 3+ /0.05Eu 3+ phosphor has great potential for use in high-power white LED applications as a single matrix.
研究领域:
材料科学
·
光学
✓ 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）