Materials Today Energy
·
2020
·
IF 5.604
Qi Sun,Shaoying Wang,Liangling Sun,Jia Liang,Balaji Devakumar,Xiaoyong Huang
At present, near-ultraviolet-pumped white light-emitting diodes (LEDs) based on tri-color (blue, green, and red) phosphors still suffer from insufficient color rendering index (CRI), due to the presence of cyan gap in the 480–520 nm spectral range. To solve this problem, it is urgent to develop an efficient cyan phosphor with emission peak around 490 nm and absorption band in the near-ultraviolet range of 380–420 nm. Herein, a highly efficient cyan-emitting Ca 2 GdHf 2 (AlO 4 ) 3 :Ce 3+ (CGHA:Ce 3+ ) garnet phosphor with internal quantum efficiency as great as 80% is reported. Impressively, the CGHA:1%Ce 3+ sample showed a broad excitation band ranging from 350 to 470 nm with a maximum at 408 nm, and upon 408 nm excitation it exhibited an intense broad cyan emission band in the 420–700 nm wavelength range with peak at 489 nm and a full width at half-maximum of 103 nm. Importantly, by applying the newly discovered cyan-emitting CGHA:1%Ce 3+ phosphors as color converter, the CRI value of the fabricated warm-white LED device is greatly enhanced from 80.5 to 91.6. This work demonstrates that the novel developed CGHA:Ce 3+ cyan phosphors could compensate for the cyan gap and realize full-visible-spectrum lighting, which have a bright prospect in high-quality solid-state white lighting.
研究领域:
材料科学
·
光学工程
·
固态照明
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2023
·
IF 3.9
Shen-Ao Hu,Bing Liu,Yu-Guo Yang,Qian Du,Yuan-Yuan Zhang,Hua-Jian Yu,Cheng-Cheng Qiu,Xu-Ping Wang,Qing-Gang Li,Ji-Yang Wang
In this paper, cyan BaLaGa 3 O 7 : Bi 3+ phosphors were synthesized by solid-state reaction method at 1400 °C. The crystal structure, elemental composition and optical properties were characterized and studied. The results of X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy and infrared spectroscopy indicate the successful synthesis of BaLaGa 3 O 7 : Bi 3+ phosphors with the pure phase. The BaLaGa 3 O 7 : Bi 3+ phosphors show wide band emission corresponding to the 3 P 1 → 1 S 0 transition of Bi 3+ when excited at 328 nm.
研究领域:
材料科学
·
光学
·
磷光技术
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Reziwanguli Yantake,Palidan Aierken,Aierken Sidike
The cyan emission band contains blue and green light regions, which can simplify the fabrication process of white light-emitting diodes and help promote the development of solid-state lighting. In this paper, a series of Eu 2+ singly doped and Eu 2+ and Li + co-doped cyan light-emitting KAlSiO 4 : x Eu 2+ , y Li + materials were synthesized using the high temperature solid-state method. It was found that the incorporation of 10% Li + could increase the emission intensity of the KAlSiO 4 :0.02Eu 2+ sample by up to a factor of ∼3. This also shifted the emission color of the sample from blue-cyan (472 nm) to cyan (485 nm), and the quantum yield was increased from 71.5% to 93.3%. When the temperature is increased to 150 °C, the peak emission intensity was increased from 75.9% to 92.7% of that at room temperature. DFT calculations were used to demonstrate that the KAlSiO 4 phosphor host possesses a wide bandgap of 4.86 eV and the experimentally-determined optical bandgap of the phosphor was 5.6 eV. The phosphor was combined with a commercial red phosphor, and these together were used as the emitting components in a white LED package. The characteristics of the white LED when using two representative samples of the phosphor (KAlSiO 4 : 0.02Eu 2+ and KAlSiO 4 : 0.02Eu 2+ , 0.1Li + ) were examined; these white LEDs had color rendering indices of 82 and 95, and color temperatures of 5656 K and 4126 K respectively. This work demonstrates the significant potential that KAlSiO 4 :0.02 Eu 2+ , 0.1 Li + phosphors have in the field of LED lighting.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2023
·
IF 3.8
Gaoliang Wang,Jian Li,Liuyang Xu,Honglei Yuan,Xianke Sun
Bi 3+ activated phosphors show potential applications in white light emitting diodes. Here, Bi 3+ activated SrBaGdGaO 5 phosphors with different Bi 3+ concentrations were prepared. The phase and oxidation states, absorbance/excitation/emission spectra, decay characteristics, and thermostability were researched. Depending on excitation of NUV light, the Bi 3+ activated SrBaGdGaO 5 phosphors emit cyan light originating from the radiative 3 P 1 → 1 S 0 transitions of Bi 3+ . On the basis of temperature-dependence emission spectra, the activation energy was calculated as 0.305 eV. The warm white light with a correlated color temperature of 4106 K and a color rendering index of 89.2 was emitted by the WLED device consisting of near ultraviolet LED chips, SrBaGdGaO 5 :Bi 3+ and CaAlSiN 3 :Eu 2+ phosphors. The luminescence performance of the cyan SrBaGdGaO 5 :Bi 3+ phosphors indicates that they can remedy the cyan absence for full spectrum white lighting emitting diodes.
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
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Zongliang Xiao,Weizhen Liu,Gan Wan,Jianlei Liu,Lu Yu,Qian Zhang,Lei Han
The quest for advanced full-spectrum lighting technologies has driven the development of W-LEDs, while challenges remain in finding effective cyan emitters and ensuring outstanding thermostability. This study detailed the synthesis of the europium-doped CaO-Al 2 O 3 -SiO 2 -YF 3 glass-ceramics (GCs), which demonstrated efficient cyan emission when irradiated by 419 nm light, with a spectacular internal quantum efficiency of up to 83.24 %, and outstanding thermal stability of 90.2 %@100℃ compared to room temperature intensity. In practical applications, this GC was integrated with a 420 nm LED chip, (Sr, Ca)AlSiN 3 : Eu 2+ red and Y 3 Al 5 O 12 : Ce 3+ yellow phosphor in a prototype full-spectrum W-LED device. The device achieved an excellent color rendering index (94), appropriate chromaticity coordinates (0.3789, 0.3950), and a well-defined correlated color temperature (4163 K). This study not only advances the application of GCs within W-LED technology but also reveals their potential in driving energy-saving and eco-friendly lighting solutions, thus providing a path to achieve superior full-spectrum lighting technology.
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
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Yue Yang,Rong Tang,Yuqi Lei,Di Gao,Houteng Zhao,Samra Jabeen,Yufeng Du,Ya Yang,Chenyi Wang,Xinyue Zhang,Ruijin Yu,Xianchao Du
To realize full-spectrum illumination systems for daily applications, the development of cyan-emitting phosphors capable of addressing the spectral deficiency in the 480-520 nm region (between blue and green emissions) has emerged as a critical research frontier in solid-state lighting technology. In this investigation, a scandium silicate phosphor, KSr 6 ScSi 4 O 16 :Eu 2+ , was initially synthesized via a high-temperature solid-state reaction under a reducing atmosphere. The target compounds crystallize in an orthorhombic system with a centrosymmetric space group of Pnma (No. 62). KSr 6 ScSi 4 O 16 :2 mol%Eu 2+ shows asymmetric broadband mainly at 481 nm under excitation of 359 nm. Based on Gaussian fitting and Van Uitert's equation, the Eu 2+ ion was confirmed to occupy two different coordination environments of Sr 2+ , producing two different luminescent centers at 477 nm and 528 nm. The optimal doping concentration of KSr 6 ScSi 4 O 16 : x Eu 2+ cyan phosphors was founded to be 2 mol%. Within the temperature range of 300 to 480 K, CIE coordinates remain stable during the heating process, and an activation energy of 0.35 eV has been determined. The color rendering index ( R a ) of the full spectrum WLED produced by KSr 6 ScSi 4 O 16 :Eu 2+ , reached 92.5, which is higher than the WLED packaged with commercial powder, effectively supplementing the cyan light component and closer to the full-spectrum lighting LEDs.
研究领域:
材料科学
·
固态照明技术
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Wei Li,Nan Ma,Balaji Devakumar,Xiaoyong Huang
In this work, novel highly efficient cyan-emitting Ce 3+ -activated CaLu 2 HfGaAl 3 O 12 (abbreviated as CLHGAO) garnet-structured phosphors were synthesized using the high-temperature solid-state reaction route. Rietveld refinement results demonstrate the as-prepared samples belong to cubic space group Ia 3 ‾ d . These CLHGAO: x Ce 3+ ( x = 0.5–8%) phosphors possessed a broad absorption band in the 320–450 nm wavelength range with a maximum at 408 nm. Upon 408 nm excitation, the CLHGAO:0.5%Ce 3+ sample showed a broad cyan emission band within 425–750 nm wavelength range (emission peak: 493 nm; bandwidth: 95 nm), along with CIE color coordinates of (0.1939, 0.3533) and a high internal quantum efficiency of 81.9%. It is observed that, with increasing Ce 3+ doping concentration from 0.5% to 8%, the emission peak position of CLHGAO: x Ce 3+ moves from 493 nm to 527 nm, and the corresponding emission color changes from cyan to green. Besides, the thermal stability and color stability of CLHGAO:0.5%Ce 3+ phosphor at high temperature are also studied. A white LED device was fabricated by utilizing a 395 nm LED chip with as-prepared CLHGAO:0.5%Ce 3+ cyan-emitting phosphor and commercial (Ba,Sr) 2 SiO 4 :Eu 2+ green-emitting phosphor and commercial CaAlSiN 3 :Eu 2+ red-emitting phosphor, and it demonstrates a high-color-quality white light with high color rendering index of 91, low color correlated temperature of 3547 K and good luminous efficacy of 58.71 lmW −1 .
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
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Halizati Abulimiti,Aierken Sidike,He Jiuyang
Highly efficient blue-cyan phosphors can fill the cyan gap in conventional white light-emitting diode (LED) devices to improve the spectral continuity while effectively increasing the white LED colour rendering index (Ra). In this study, Ba 0·94 Al 2- x Ga x Si 2 O 8 :0.06Ce 3+ , M + (Li, Na, K, x = 0–0.8) blue-cyan phosphors with a feldspar structure were prepared by a high-temperature solid-phase method using charge compensation and cation substitution strategies. The barium (Ba) vacancy due to the charge-imbalance substitution of Ce 3+ is compensated by the different charge compensators Li + , Na + , and K + . The charge compensators affect the luminescence performance of the samples, with the K + -compensated samples showing the greatest enhancement, with intensities up to 1.8 times that of the uncompensated samples. The cation substitution strategy using Ga 3+ to partially replace Al 3+ further improves the luminescence performance of the Ba 0·94 Al 2 Si 2 O 8 :0.06Ce 3+ , 0.04 K + sample, and the excitation band is also improved. In this case, the luminescence intensity of the Ba 0·94 Al 2 Si 2 O 8 :0.06Ce 3+ luminescent material is increased by a factor of 6, and a broadband blue-cyan phosphor with a full-width at half-maximum of 118 nm containing blue, cyan and green is obtained. The co-doping of charge compensators and partial cation substitution improved the luminescence performance of phosphors. The representative sample Ba 0·94 Al 1.6 Ga 0.4 Si 2 O 8 :0.06Ce 3+ , 0.04 K + has a luminescence intensity at a temperature of 150 °C that is 83.2% of that at room temperature and good thermal stability . The combination of 365 nm near-ultraviolet (NUV) LED chips with Ba 0·94 Al 1.6 Ga 0.4 Si 2 O 8 :0.06Ce 3+ , 0.04 K + and the commercial red powder (Ca, Sr)AlSiN 3 :Eu 2+ yields a white LED device with an Ra of up to 93 and a correlated colour temperature (CCT) of 4825 K. These results show that the blue-cyan phosphor complements the cyan component while simplifying the manufacturing process of white LEDs.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2023
·Vol. 33
·期 25
·2300583
·
IF 19
Min Peng,Shibin Sun,Bin Xu,Zhengtao Deng
Currently, the most popular way to manufacture white light-emitting diodes (WLEDs) is based on blue-emitting InGaN LED chips (440–460 nm) and yellow-emitting phosphor coating (520–700 nm) to produce white light lighting. However, because conventional white WLEDs lack the uniformly distributed continuous emission spectrum compared to natural sunlight: “blue overshoot” (extra 440–460 nm blue-light can cause damage to the retina) and “cyan gap” (470–520 nm wavelength range). Here, a novel strategy to “kill two birds with one stone” is reported: using the stable and bright polymer encapsulated perovskite nanocrystals (PNCs) composite films as the cyan color converters that efficiently absorb the “blue overshoot” and effectively emit the cyan light to fill the “cyan gap”. A series of polymer-encapsulated PNC films is achieved that can reach very high photoluminescence quantum yield (PL QY) of 90–95% under 450 nm blue-light excitation. Importantly, both 370 nm UV-excited WLED and 455 nm blue-excited WLED devices are constructed that exhibit smoothly and evenly distributed white light without blue overshoot and cyan gap, which was not achieved before for blue-excited cyan-emissive materials. This study paves the way toward the application of PNC color converters in the next generation full-visible-spectrum WLED lighting that mimic the natural daylight.
研究领域:
材料科学
·
光学工程
·
纳米技术
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Rong Zhang,Jian-Feng Sun
Along with the development of versatile trichromatic phosphors, the phosphors bridging the cyan gap between blue and green light have been an ongoing focus in simulating the full-visible-spectrum luminescence to satisfy the daily illuminating demands. Herein, an intriguing cyan-emitting phosphor Rb 2 CaPO 4 F:Eu 2+ belonging to the perovskite-type structural prototype was first time synthesized via the solid-state reaction. Structural analysis indicated that the typical Rb 2 Ca 0.90 PO 4 F:0.10Eu 2+ phosphor crystallizes in the orthorhombic structure with the space group of Pnma (62), and its cell parameters are equal to a = 12.913(5) Å, b = 5.989(4) Å, c = 7.440(1) Å, and V = 575.44(8) Å 3 . The fluorine-centered [FRb 4 Ca 2 ] octahedra interconnect with each other by sharing faces to build the one-dimensional perovskite-structure corrugated chains, which further connect with the [PO 4 ] tetrahedra to establish the structural framework of Rb 2 CaPO 4 F host. The electronic structure of Rb 2 CaPO 4 F matrix was studied by the first-principle calculation on the basis of the density functional theory, revealing an appropriate direct band of 4.76 eV. Pumped with the near-ultraviolet light, Rb 2 CaPO 4 F:Eu 2+ phosphor displayed a bright cyan emission covering from 400 to 600 nm with a broad FWHM of 142 nm. According to the Dexter theory, the concentration quenching mechanism of Eu 2+ -activated Rb 2 CaPO 4 F phosphor was classified as the dipole-dipole interaction. The Rb 2 CaPO 4 F:Eu 2+ phosphor not only exhibits a good thermal stability (I 443 K /I 298 K = 70%), but possesses a satisfactory internal quantum efficiency of 68% which is superior to most of the previously reported cyan-emitting phosphors. Consequently, it turns out that our perovskite-type Rb 2 CaPO 4 F:Eu 2+ phosphor can be considered as a promising candidate to fill the cyan gap toward the full-visible-spectrum light. The present work also demonstrates a great possibility for exploring the novel phosphors inspired by the mineral-type structural prototypes.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
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
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2022
·Vol. 9
·期 21
·5590-5596
·
IF 7.779
Yuhe Shao,Hao Cai,Fangyi Zhao,Shengqiang Liu,Zhen Song,Quanlin Liu
In order to realize full-spectrum lighting, excellent blue-cyan phosphors, which can be excited by violet LED chips, are particularly important to compensate for the spectral cyan gap. Herein, we report an efficient and thermally stable Eu2+-doped T-phase blue-cyan phosphor, Ba1.305Ca0.38Mg0.3SiO4:0.015Eu2+ (BCM0.3S:Eu2+) through structure design and composition optimization. The emission spectrum presents an asymmetric band peaking at 475 nm with a small Stokes shift under 400 nm excitation. The internal/external quantum efficiencies of this phosphor are up to 82.9%/66.2%, and the integrated emission intensity at 150 °C is maintained at 90% of that at room temperature. Due to the compensation of the blue-cyan gap, the fabricated white light-emitting diode (pc-WLED), made of BCM0.3S:Eu2+ combined with the 400 nm chip and other phosphors, shows an ultra-high color rendering index (Ra = 95.7). These prominent properties give BCM0.3S:Eu2+ potential applications in the field of full-spectrum healthy lighting.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）