INORGANIC CHEMISTRY COMMUNICATIONS
·
2024
·
IF 4.4
Houteng Zhao,Yilian Ran,Xiya Miao,Siyu Cheng,Dongze Li,Yufeng Du,Xiang Liu,Ruijin Yu
A series of novel phosphors, doping Eu 3+ and Na + ions in the Sr 3 MgNb 2 O 9 (SMNO) crystal lattice (SMNO: x Eu 3+ , x Na + , x = 0.5–30 mol%), was successfully synthesized through high-temperature solid-state reaction. X-ray diffraction (XRD) analysis and Rietveld refinement confirmed the successful synthesis of SMNO:Eu 3+ , Na + . The phosphor belongs to the hexagonal crystal system and the P 3 ¯ m 1 (No.164) space group. The bandgap energy of SMNO was calculated with Materials Studio and measured with the use of diffuse reflectance spectroscopy. The excitation spectrum of SMNO:Eu 3+ , Na + displays multiple narrow absorption peaks in the violet-blue region as well as a charge transfer band (CTB) near 300 nm, exhibiting the highest peak at 394 nm. Four distinct characteristic peaks are observed in the emission spectrum of SMNO:Eu 3+ , Na + . Notably, the peak at 601 nm shows the highest emission intensity due to the radiative transition from 5 D 0 → 7 F 2 . By varying doping concentrations, it was determined that an optimal concentration of 5 mol%Eu 3+ resulted in phosphors, with high color purity exceeding 99 %. Concentration quenching is attributed to the nearest neighbor ions interaction. Furthermore, SMNO:Eu 3+ , Na + exhibited good stability in 300–480 K, with luminescent intensity remaining 68.6 % at 420 K and 54.4 % at 480 K compared to room temperature (300 K). The internal quantum efficiency (IQE) of SMNO:5%Eu 3+ , 5 %Na + is 65.0 %. Both red and white light-emitting diodes (LEDs) were prepared using SMNO:Eu 3+ , Na + . The chromaticity coordinates of w-LED were measured as (0.357, 0.376), correlating to a correlated color temperature (CCT) of 4685 K and exhibiting a good color rendering index (CRI, R a = 88). Additionally, the latent fingerprint (LFP) development demonstrated clear visualization of Levels I-III characteristic structures of fingerprints when utilizing SMNO:Eu 3+ , Na + . These findings suggest promising applications for SMNO:Eu 3+ , Na + in w-LED lighting and LFP development.
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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
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高影响因子
AIP Advances
·
2022
·Vol. 12
·期 5
·
IF 1.697
Tu Huan,Zhao Guoying,Hou Jingshan,Liu Yufeng,Zhou Yan,Zhang Ganghua,Sun Hong-Tao,Li Ji-Guang,Fang Yongzheng
White light emitting diodes (LEDs) suffer from two most common drawbacks: the deficiency of the red component and the poor thermal stability of silicone. Ce 3+ -doped garnet phosphors with tailor-made luminescence properties can be achieved by variations in {A}, {B}, and {C} cation sites. Herein, a simultaneous ion co-substitution design strategy has been adopted to synthesize a series of (Y, Ca) 3 (Al, Mg) 2 (Al, Si) 3 O 12 garnet phosphors and corresponding phosphor-in-glass (PiG) films. The co-substitution is finely restricted to the assigned sites. The emission peak is shifted from 529 to 565 nm, which is beneficial to obtain low color temperatures and high color rendering using a single phosphor for white LEDs. By employing the as-synthesized phosphor, the corresponding PiG films were fabricated by the low temperature co-sintering technology using the SiO 2 –B 2 O 3 –ZnO–Na 2 O glass system characterized with excellent thermal stability and moisture resistance. The morphological and elemental analyses demonstrated that the as-made phosphor powders were uniformly distributed in the glass host without any interfacial reactions. Finally, modular white LEDs with a high color rendering (Ra = 82.7) is achieved through the as-synthesized PiG film on an InGaN blue chip. This study may open up a facile approach to obtain high quality luminescence based on the mono-luminescence center, avoiding excitation energy wastage and low quantum efficiency aroused by multi-luminescence centers or color compensation phosphors in glass.
研究领域:
材料科学
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光电子学
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固态照明
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无机化学
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应用物理学
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高影响因子
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.
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高影响因子
JOURNAL OF LUMINESCENCE
·
2026
·
IF 3.8
Viswadevarayalu Annavaram,Weicheng Xiang,Zihang Chai,Kangwei Zhu,Zaifa Pan
Enhanced quantum-cutting (QC) materials are highly desirable for promising applications such as solar cells. In this work, a series of Ce 3+ , Gd 3+ , and Yb 3+ tri-doped phosphors using Y 2 SiO 5 as the host were synthesized via a solid-state reaction. X-ray diffraction confirms that the dopants do not alter the monoclinic phase of Y 2 SiO 5 . Photoluminescence spectroscopy reveals that, the optimized tri-doped phosphor exhibits intense near-infrared (NIR) emission centered at 976 nm under UV excitation. Mechanism investigation reveals that Gd 3+ preferentially occupies the 7-coordinate Y2 site (associated with the Ce 3+ 392-nm emission), displacing Ce 3+ ions toward the 6-coordinate Y1 site (associated with the 425-nm emission). The Y1-site Ce 3+ emission at ∼425 nm (≈23,500 cm −1 ) is energetically closer to twice the Yb 3+ absorption energy (≈20,000 cm −1 ) than the Y2-site emission at ∼392 nm (≈25,500 cm −1 ), making the Y1 site more favorable for cooperative energy transfer to Yb 3+ pairs. This site-selective occupation effect significantly enhances the quantum-cutting efficiency. Furthermore, the synthesized tri-doped phosphor demonstrates superior performance in NIR phosphor-converted LEDs (pc-LEDs), achieving an electrical-to-optical conversion efficiency 1.55 times that of the co-doped counterpart. The output power of the tri-doped NIR LED is enhanced to 206.4% of that of the co-doped device. For solar cell applications, the short-circuit current density (J SC ) of the tri-doped device reaches 2.47 mA/cm 2 , with a power conversion efficiency (η) of 10.58%. The tri-doped phosphor solar cell exhibits an extra 0.1% enhancement in conversion efficiency compared to the co-doped counterpart. These results highlight the potential of Y 2 SiO 5 :Ce 3+ ,Gd 3+ ,Yb 3+ as an efficient spectral converter for boosting the energy yield of silicon photovoltaics.
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高影响因子
ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Jiasheng Li,Yong Tang,Zongtao Li,Xinrui Ding,Binhai Yu,Liwei Lin
Quantum-dot (QD) white light-emitting diodes (LEDs) are promising for illumination and display applications due to their excellent color quality. Although they have a high quantum yield close to unity, the reabsorption of QD light leads to high conversion loss, significantly reducing the luminous efficacy and stability of QD white LEDs. In this report, SBA-15 mesoporous particles (MPs) with two-dimensional hexagonal pore structures (2D-HPS) are utilized to largely enhance the luminous efficacy and color-conversion efficiency of QD white LEDs in excess of 50%. The reduction in conversion loss also helps QD white LEDs to achieve a lifetime 1.9 times longer than that of LEDs using QD-only composites at harsh aging conditions. Simulation and testing results suggest that the waveguide effect of 2D-HPS helps in reducing the reabsorption loss by constraining the QD light inside the wall of 2D-HPS, decreasing the probability of being captured by QDs inside the hole of 2D-HPS. As such, materials and mechanisms like SBA-15 MPs with 2D-HPS could provide a new path to improve the photon management of QD light, comprehensively enhancing the performances of QD white LEDs.
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PubMed
高影响因子
OPTICS COMMUNICATIONS
·
2018
·
IF 1.887
Wu Yang,Wanlu Zhang,Guilin Zhang,Jiatao Zhu,Guoxing He,Ruiqian Guo
We reported two types of tunable white LEDs (WLEDs) based on high quality the single emissive InP/ZnS quantum dots (QDs) and the dual emissive Ag:InP/ZnS QDs via myristic acid (MA) passivation and Ag doping. The WLEDs with three color InP/ZnS QDs could realize color rendering indices (CRIs) of 97–98, color quality scales (CQSs) of 94–98, and limited luminous efficacies (LLEs) of 238–246 lm/W at correlated color temperatures (CCTs) of 2700 K to 6500 K, and the WLEDs with dual emissive Ag:InP/ZnS and red emissive InP/ZnS QDs could realize CRIs of 90–93, CQSs of 90–93, and LLEs of 223–242 lm/W at CCTs of 2700 K to 4000 K. Finally, their luminous efficacies were estimated.
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高影响因子
JOURNAL OF LUMINESCENCE
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2020
·
IF 3.28
Yaochun Qiang,Yanan Liu,Jiayuan Chen,Shaopeng Liu,Lulu Zhang,Haojian Kang,Feiyan Xu,Zongliang Xiao,Weixiong You,Lei Han,Xinyu Ye
It is well known that green-emitting phosphor plays a key role in a phosphor-converted white LED with high color rendering index. Here, a novel green phosphor BaY 1·95 Al 2 Ga 2 SiO 12 :0.05Ce 3+ with high quantum yield , low thermal quenching and excellent water resistance is reported. The green phosphor can be easily prepared by the conventional solid-state reaction method at 1325 °C for 4 h in a reducing atmosphere. The compound is cubic and crystallizes in space group I a 3 ‾ d with refined lattice parameters of a = 12.1451(3) Å. The phosphor can be effectively excited by the mainstream commercial blue LEDs (445–465 nm), its emission peak is observed at 517 nm and the absolute quantum yield under 450 nm excitation is as high as 96.2% at 25 °C. The green phosphor exhibits good resistance toward thermal quenching, with the luminescence intensity at 150 °C only decreasing by 11% of the value at 25 °C. In addition, the green phosphor has a very good water resistance, and its luminescence intensity remains almost unchanged when it is soaked in water for more than 300 h. The white LED fabricated by employing the green phosphor shows excellent optical properties with Ra = 92.4, CCT = 3304 K and CIE 1931 chromaticity coordinates as (x = 0.4178, y = 0.3985). All experimental results indicate that BaY 1·95 Al 2 Ga 2 SiO 12 :0.05Ce 3+ is an outstanding green phosphor which has great potential to be used for the phosphor-converted white LEDs with excellent color rendering.
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高影响因子
JOURNAL OF RARE EARTHS
·
2026
·
IF 9.6
Biao Xu,Zihao Xu,Chunyu Li,Jian Peng,Xingyu Li,Wubin Dai
Phosphor with thermally stable and highly efficient photoluminescence (PL) is a premise/challenge for use in high-quality phosphor-converted light-emitting diodes (pc-LEDs). Herein, via a facile solid-phase sintering method in air, a negative thermal quenching (TQ) blue emitting SrGa 2 B 2 O 7 (SGB): Bi is reported, mainly associating with the underlying collaborative effect of negative volumetric thermal expansion of rigid host, heterovalent substitution (Bi 3+ → Sr 2+ )-induced V Sr /V O vacancies, and generating self-reduction ions (Bi 2+ ). For charge balance under the condition of temperature rising, both opposite process of self-oxidation (Bi 2+ to Bi 3+ ) and charge release from trap levels can compensate blue-PL loss. This phosphor is comparable to Eu 2+ /Ce 3+ -activated blue-emitting phosphors, and even boasts superior quantum efficiency (QE) and thermal stability. Via artificially codoping Na + for charge compensation, the QE of the SGB:Bi/Na can be further significantly enhanced. Color-tunable PL is achieved via cascade-connected energy transfer (ET) from Bi 3+ to Tb 3+ (green)/Eu 3+ (red) in SGB: Bi/Na/Tb/Eu that possesses high QE/stability than the case of blue/green/red tricolor phosphor blends adopted in warm white LEDs (wLEDs). Finally, the SGB: Bi/Na and SGB: Bi/Tb/Eu/Na are respectively, encapsulated with distinct encapsulants via either traditional or remote “capping” packaging strategy to form blue LEDs and wLEDs, showcasing splendid electroluminescence behaviors and luciferous application prospects.
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高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Dong Yi,Jiawei Fu,Fenzhong Long,Jin Han,Fangui Meng,Xinmin Zhang
To improve the quality of white LED and develop plant growth lighting, considerable efforts have been devoted to investigating red phosphor. Eu 3+ -activated phosphors are well-known red-emitting components due to their 5 D 0 - 7 F 1,2 transitions in various applications. It is also found that its 5 D 0 - 7 F 4 transition in the range of far-red wavelengths has potential applications in the fields of daily and agricultural lighting. In this study, two kinds of Eu 3+ -doped layered perovskite La 2 Ti 2 O 7 and A 2 La 2 Ti 3 O 10 (A = Li, Na, K) phosphors were synthesized by the solid-state method. The crystal structure, absorption, excitation, and emission spectra of all the samples were investigated in detail. Dissimilar luminescent behaviors of the studied samples were observed. Due to the different crystal structure and chemical composition of the host matrix, each compound exhibits a different emission spectrum. Specifically, Eu 3+ occupies a lower symmetric La 3+ site in A 2 La 2 Ti 3 O 10 (A = Li, Na, K) phosphors, resulting in an intense 5 D 0 - 7 F 4 far-red emission, while in La 2 Ti 2 O 7 :Eu 3+ , Eu 3+ gives a weak 5 D 0 - 7 F 4 emission. To the best of our knowledge, this is the first report that Eu 3+ exhibits a strong 5 D 0 - 7 F 4 far-red emission in the titanate host lattices with perovskite structure. Besides, A 2 La 2 Ti 3 O 10 :Eu 3+ (A = Li, Na, K) phosphors achieve higher photoluminescence efficiency than La 2 Ti 2 O 7 :Eu 3+ . Among them, the internal quantum efficiency of the optimized Li 2 La 2 Ti 3 O 10 :1.2Eu 3+ is about 84.7 %, and it has a better thermal stability (80 % at 125 °C). Furthermore, good photoelectric performances of red/white-LEDs fabricated by utilizing the representative Li 2 La 2 Ti 3 O 10 :1.2Eu 3+ as red/far-red components indicate that it has potential applications in indoor/outdoor lighting and plant growth lighting. This study provides a feasible way for developing efficient Eu 3+ -activated far-red optical materials.
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高影响因子
Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 34
·10471-10480
·
IF 6.641
Liangling Sun,Balaji Devakumar,Jia Liang,Shaoying Wang,Qi Sun,Xiaoyong Huang
Inorganic phosphors play an important role in realizing high-performance white light-emitting diodes (LEDs), and thus highly luminescent phosphors with excellent optical properties are urgently needed. In this paper, novel Ce3+/Tb3+ co-doped Ca2YZr2(AlO4)3 (abbreviated as: CYZA) green-emitting phosphors with broadband excitation and high quantum efficiency were synthesized for potential application in white LEDs, and their phase purity, crystal structure, morphology, photoluminescence properties, energy transfer mechanism, and thermal stability were systematically investigated. It was found that the CYZA:Ce3+,Tb3+ phosphors exhibited two broad excitation bands in the 300–470 nm wavelength range, due to the highly efficient energy transfer from Ce3+ to Tb3+ ions. Under the excitation wavelength of 408 nm, the CYZA:Ce3+,Tb3+ phosphors showed bright green emissions around 492, 543, 591, and 628 nm originating from the 5D4 → 7FJ (J = 6, 5, 4, and 3) transitions of Tb3+ ions. The optimal doping concentrations of Ce3+ and Tb3+ ions in CYZA:xCe3+,yTb3+ phosphors were determined to be x = 0.04 and y = 0.9, respectively. The CIE coordinates and the internal quantum efficiency of the composition-optimized CYZA:0.04Ce3+,0.9Tb3+ phosphors were measured to be (0.342, 0.545) and 56%, respectively. The full width at half-maximum (FWHM) of the dominant green emission band around 543 nm was only about 13.5 nm. Finally, a white LED lamp was fabricated using a 400 nm LED chip together with a phosphor blend of blue-emitting BaMgAl10O17:Eu2+, green-emitting CYZA:0.04Ce3+,0.9Tb3+ and red-emitting CaAlSiN3:Eu2+, which produced warm white light with color coordinates of (0.419, 0.392), excellent color rendering index of 91, correlated color temperature of 3233 K, and luminous efficacy of 30 lm W−1 when driven by a 40 mA current. The above results demonstrated that CYZA:0.04Ce3+,0.9Tb3+ can be a potential green-emitting color converter for white LEDs.
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高影响因子
Journal of Materials Chemistry C
·
2024
·
IF 5.7
Wenrui Zhang,Yayun Zhou,Ce Shi,Jiajun Ren,Liying Zhang,Haipeng Ji
Mn4+-activated fluoride phosphors are some of the crucial red-emitting phosphors for white lighting systems driven by light-emitting diodes (LEDs). In this study, we successfully synthesized high-quality K2Si1−xF6:xMn4+ (nominal x = 0.03–0.70, measured x of 0.22%–33.3%) crystals, measuring approximately 1 mm in size, through a new cooling-induced crystallization method. These crystals exhibit narrow line-type photoluminescence emission bands and exceptional optical properties, including a high absorption efficiency of up to 92.9% and an external quantum efficiency of up to 78.5%, which are among the record values for Mn4+-doped fluoride phosphors. Furthermore, they exhibit a notably elevated luminescence thermal quenching temperature (T1/2) exceeding 500 K. A comprehensive investigation into the phase transformation, zero-phonon line tuning, and fluorescence decay behavior as a function of increasing Mn concentrations was also conducted. Practical applications were demonstrated through the fabrication of warm white LEDs, integrating a blue LED with a garnet yellow phosphor and the as-synthesized K2Si1−xF6:xMn4+ (measured x of 2.94%) crystals as the red component. The white LEDs exhibit an impressive luminous efficacy of 192.1 lm W−1, a color rendering index of Ra = 87.5 and R9 = 62 under a 20 mA driving current. Our study highlights the outstanding properties of Mn4+-doped fluoride crystals with bulk size rather than conventional powdery form and the potential of the cooling-induced crystallization method for cultivating the crystals.
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高影响因子
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