JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2017
·Vol. 28
·期 13
·9464-9470
·
IF 2.019
Xing Yangyang,Zhu Yingchun,Chang Chengkang,Wang Yunli,Wang Yang
Eu 2+ -doped β-Sialon phosphors with a composition of Eu
x
Si 5 Al 1− x
O z+ x
N 8−z− x
( x = 0.05, 0.06, 0.07) were synthesized in a new synthetic route using novel raw materials, such as nano-silicon dioxide (SiO 2 ), nano-carbon (C), and aluminum (Al). This is different from the prevailing method using Si 3 N 4 , AlN, and Al 2 O 3 to obtain β-Sialon phosphors. Compared with the conventional method, lower cost raw materials, simpler pretreatment and a relatively shorter reaction time are achieved. The phosphors show a high purity. All the phosphors exhibit green emission under ultra violet (UV) radiation. A broad band of excitation spectra implies the promising application in UV ray based green light-emitting diode (LED). Chromaticity coordinates of the β-Sialon: Eu 2+ phosphors demonstrate that it is accessible to obtain different green emissions from single phase of Eu 2+ -doped β-Sialon through adjusting Eu 2 O 3 concentration. Furthermore, the Eu
x
Si 5 Al 1− x
O 1 + x
N 7 − x
( x = 0.05) shows a better thermal stability than the commercial green-emitting silicate phosphor. These results indicate a promising prospect for this efficient and economic route in preparing β-Sialon: Eu 2+ phosphors, and the phosphors are a highly promising candidate for LED applications.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Zelong Jiang,Tao Hu,Fanchao Men,Hong Yang,Wei Lv,Dawei Wen,Qingguang Zeng,Yan Gao
The pursuit of efficient red emitting Eu 2+ doped oxide is endless, aiming to replace the state-of-the-art CaAlSiN 3 :Eu 2+ nitride counterpart to achieve cheaper and more stable warm illumination. Herein, we identify a hitherto unreported CaLuGaO 4 olivine compound. The crystal structure of the compound is belong to orthorhombic Pnma . Phonon dispersion relations have no imaginary frequency, verifying thermodynamic stability of the crystal structure. It structurally contains an octahedral Ca 2+ site that definitely has strong crystal field splitting energy, which motivates us to incorporate it with Eu 2+ to realize red emission through 4 f 6 5 d 1 → 4 f 7 transition of the octhdedral Eu 2+ ion. This goal is achieved as found the divalent Eu 2+ is necessarily stabilized in this site under CO sintering atmosphere rather than H 2 /N 2 . The as-designed CaLuGaO 4 :Eu 2+ exhibits impressively appealing properties, i.e., intense red emission at 650 nm (λ ex = 450 nm), with high PLQY up to 86 % and good thermal stability in temperature range 10–500 K, marking it as a promising and formidable red phosphor in warm illumination. The excellent emission properties are theoretically revealed to associate with the closed-packed dimensional crystal structure with high Debye temperature equals 440 K, which reduces the non-radiative recombination loss. The investigations in electron-vibrational interaction in the Eu 2+ :5 d state disclosing the interaction is intermediate coupling regime with Huang-Rhys factor of 4.3. As a proof-of-concept experiment of the red phosphor for illumination, a prototype WLED possession of low CCT = 3917 K, high Ra = 92.2, and excellent luminous efficiency = 110 lm/W is constructed, and a portable rechargeable LED flashlight is assembled, by utilizing CaLuGaO 4 :Eu 2+ phosphor as a key red convector. Moreover, we have also demonstrated the phosphor synthesized under H 2 /N 2 can apply for latent fingerprint visualization.
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
DALTON TRANSACTIONS
·
2022
·Vol. 51
·期 11
·4414-4422
·
IF 4.569
Zhi Wang,Xu Li,Mingyang Li,Jinxing Zhao,Zhenyang Liu,Dawei Wang,Li Guan,Fenghe Wang
With the increasing demand for new inorganic functional materials, more and more attention is paid to rare earth ion doped luminescent materials. In this work, an Eu2+ doped Ba4La6O(SiO4)6 phosphor was synthesized by the high temperature solid-phase method. In the phosphor, two Ba2+ sites could be occupied by Eu2+ cations to provide two different kinds of coordination environments, resulting in broad emitting bands in the range of 450–630 nm and ultra-wide excitation bands in the range of 250–500 nm. The presence of two different Eu2+ emitting centers is verified by measuring the photoluminescence spectra and decay curves in Ba4La6O(SiO4)6 phosphors. The temperature dependence of emission intensity and full width at half maximum of Eu2+ in the range of 293–453 K were investigated systematically. The substitution of Ba2+ by Sr2+ can adjust the crystal field; thus, the luminous intensity was improved by 2.07 times and T50 was increased from 380 K to 453 K. Due to the Sr2+ ion doping, some of the Eu3+ ions cannot be reduced and remain in the trivalent state. In addition, by integrating the as-prepared Ba1.42Sr2.5La6O(SiO4)6:Eu phosphor, commercial blue and red phosphors, and a 385 nm LED chip, a white-LED lamp was made, which realized an applicable color rendering index (Ra = 94.6). For the Ba0.42Sr3.5La6O(SiO4)6 phosphor, the emission can be shifted from yellow to green and to yellow by excitation wavelength variation from 250 to 360 and 480 nm, which proves that the phosphor is a promising candidate for anti-counterfeiting applications.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry C
·
2022
·Vol. 10
·期 25
·9636-9643
·
IF 8.067
Kuangnan Lyu,Enhai Song,Zhiguo Xia
Doping engineering in lead-free all-inorganic halide perovskites plays an important role in their performance modulation for emerging photonics applications. Benefiting from the weak electron phonon coupling effect, and the distorted site occupied by Eu2+, chloride perovskite phosphor KCaCl3 : Eu2+ is prepared and demonstrated herein, which shows high-efficiency (internal quantum efficiency, IQE = 96.1%) blue emission peaking at ∼430 nm as well as good thermal stability (74%@ 423 K of the initial integrated intensity at 298 K). This phosphor also has high radiation luminescence intensity (∼7.1 times that of commercial Lu3Al5O12 : Ce3+) upon X-ray excitation and a low detection limit (483.5 nGyair s−1), exhibiting good potential in X-ray detection and imaging. This work provides new insights into the design of Eu2+ activated halide perovskite luminescent materials for versatile optoelectronic 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
Scientific Reports
·
2017
·Vol. 7
·期 1
·1-14
·
IF 4.259
Wang Baochen,Liu Yan-gai,Huang Zhaohui,Fang Minghao,Wu Xiaowen
Discovery of novel phosphors is one of the main issues for improving the color rendering index (CRI) and correlated color temperature (CCT) of white light-emitting diodes (w-LEDs). This study mainly presents a systematic research on the synthesis, crystal structure variation and photoluminescence tuning of novel (oxy)nitride solid solution Ca 3 Si 3− x
O 3+ x
N 4−2 x
: Eu 2+ phosphors. XRD refinements show that lattice distortion occurs when x value diverges the optimum one ( x = 1). The lattice distortion causes a widening of emission spectrum and an increase of Stokes shift (ΔSS), which leads to a bigger thermal quenching. With decrease of x value, the emission spectrum shows an obvious red-shift from 505.2 to 540.8 nm, which is attributed to the crystal field splitting. The enhanced crystal field splitting also broadens the excitation spectrum, making it possible to serve as the phosphor for near ultraviolet (n-UV) LEDs. A 3-phosphor-conversion w-LED lamp was fabricated with the as-prepared phosphor, which exhibits high CRI (Ra = 85.29) and suitable CCT (4903.35 K). All these results indicate that the Ca 3 Si 3− x
O 3+ x
N 4−2 x
: Eu 2+ phosphor can serve as the green phosphor for n-UV w-LEDs, with a tunable spectrum by controlling the crystal structure and morphology.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
Advanced Optical Materials
·
2022
·Vol. 10
·期 6
·2102373
·
IF 10.05
Zhiyu Yang,Gaochao Liu,Yifei Zhao,Yayun Zhou,Jianwei Qiao,Maxim S. Molokeev,Hendrik C. Swart,Zhiguo Xia
The discovery of Eu 2+ -doped high-efficiency red phosphors remains a vital challenge for white light-emitting diode (WLED) applications. It is therefore urgent to find effective strategies managing the oxidation state to help reduce Eu 3+ to Eu 2+ and accordingly increase the photoluminescence quantum yield (PLQY). Herein, a new red-emitting SrLaScO 4 :Eu phosphor is designed, and the PLQY is enhanced from 13% to 67% under 450 nm excitation by employing (NH 4 ) 2 SO 4 -assisted sintering. Combined structural analysis, optical spectroscopy, and theoretical calculation reveal that predominant Eu 2+ prefers to occupy the Sr 2+ sites in the SrLaScO 4 enabling red emission, and a competitive site occupation of Eu 3+ in La 3+ can be restrained, and the reduction mechanism of Eu 3+ to Eu 2+ originating from the (NH 4 ) 2 SO 4 addition is analyzed. The fabricated WLED device using red-emitting SrLaScO 4 :Eu and yellow-emitting Y 3 (Al,Ga) 5 O 12 :Ce 3+ exhibits a high color-rendering index of 86.7 at a low correlated color temperature of 4005 K. This work provides a feasible reduction strategy for guiding the development of high-efficiency Eu 2+ -doped red phosphor for WLED applications.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2020
·
IF 4.825
Dan Zhao,Shi-Rui Zhang,Yan-Ping Fan,Bao-Zhong Liu,Rui-Juan Zhang
The relationship between the structure and properties is always a hot topic in the luminescent material field. In this work, a new phosphor KBa2(PO3)5:Eu2+ (KBP:Eu) was prepared by a high-temperature solid-state reaction method and characterized by X-ray diffraction, energy-dispersive X-ray spectroscopy, photoluminescence (PL), and electroluminescence studies. The polyphosphate host KBP offers three lattice environments (K1, Ba1, and Ba2) for Eu2+ ions to realize broad-band emission from 380 to 700 nm under 345 nm excitation. The distributions of Eu2+ in the three lattice sites can be proven by low-temperature PL and transient fluorescence spectroscopy. Furthermore, temperature-dependent luminescence studies for phosphor KBP:0.02Eu reveal that its luminescence intensity at 150 °C retains about 97% of the initial value at 25 °C. By composing a 365 nm UV chip and KBP:0.02Eu, CaAlSiN3:Eu2+ phosphors, a warm white-light-emitting diode (WLED) was obtained with a correlated color temperature of 5146 K and chromaticity coordinates (0.3404, 0.3384). Therefore, KBP:Eu phosphor is a potential cyan-emitting phosphor used for high-power WLEDs.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
ACS Materials Au
·
2022
·
IF 0
Shunqi Lai,Ming Zhao,Yifei Zhao,Maxim S. Molokeev,Zhiguo Xia
Regulation of Eu2+ dopants in different cation sites of solid-state materials is of great significance for designing multicolor phosphors for light-emitting diodes (LEDs). Herein, we report the selective occupation of Eu2+ for multiple cationic sites in KSrScSi2O7, and the tunable photoluminescence from blue to cyan is realized through Eu2+ doping concentration-dependent crystal-site engineering. Eu2+ preferably occupies the K and Sr sites in KSrScSi2O7 at a low doping concentration, resulting in a 440 nm blue emission. As the Eu2+ concentration increases, a new Eu2+ substitution pathway is triggered, that is, Eu2+ enters the Sc site, leading to the red-shifted emission spectra from 440 to 485 nm. The doping mechanism and photoluminescence properties are corroborated by structural analysis, optical spectroscopy study, and density functional theory calculations. The optical properties of the as-fabricated white LEDs are studied, which demonstrates that these phosphors can be applied to full-spectrum phosphor-converted LEDs. This study provides a new design strategy to guide the development of multicolor Eu2+-doped oxide phosphors for lighting applications.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Yongsheng Sun,Xinquan Zhou,Zhenjie Lun,Kai Han,Puxian Xiong,Zhiguo Xia
Multi-mode luminescence tuning through in situ crystallization of topological glass holds significance for photonics applications. Here, NaAlSiO 4 :Eu 2+ -based glass ceramics are presented as stable persistent luminescence (PersL) materials by controlling the phase transformation in Eu 2+ doped Na 2 O-Al 2 O 3 -SiO 2 from amorphous glass to crystalline nepheline phase. X-ray and UV excited PersL colors from blue to yellow are realized by adjusting the crystallization duration time, and trap statuses reveal the dynamic PersL process with a trap redeployment from 0.83 to 1.09 eV during the transformation. Optical information storage model is constructed with a structure of stacked emitting layers to enhance storage capacity. X-ray excited luminescence time-lapse imaging is further demonstrated with optical memory longer than 5 days. These findings advance the development of superior stable PersL glass ceramics and offer optical manipulation tactics for multi-mode optical information storage 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
CHEMICAL PHYSICS
·
2024
·
IF 2
Xuan Gu,Zheng He,Xao-Yu Sun
Eu 2+ -doped Sr 2 LaGaO 5 phosphors were prepared using a high-temperature solid-state route in a furnace at 1450 °C. Their phase, microstructure, and luminescent performance were thoroughly investigated. The XRD measurements indicate that the prepared phosphors exhibit a tetragonal phase. Upon excitation at 450 nm, the Sr 2 LaGaO 5 :Eu 2+ phosphors demonstrate a broad red emission ranging from 475 to 850 nm, with a peak at 620 nm. At a doping concentration of 6 %mol Eu 2+ , the phosphors exhibit the highest emission intensity, characterized by CIE coordinates of (0.536, 0.453) and a color purity of 65.53 %. The temperature-dependent emission analysis reveals that the phosphors possess excellent thermal stability. The emission intensity of the Sr 2 LaGaO 5 :0.06Eu 2+ phosphor at 420 K is about 53.9 % of the initial intensity measured at 300 K, with a thermal activation energy of 0.393 eV. The pc-WLED device was constructed via the combination of an LED chip, yellow Y 3 Al 5 O 12 :Ce 3+ and the prepared Sr 2 LaGaO 5 :Eu 2+ phosphors, resulting in the emission of warm white light with a CCT value of 4985 K.
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
·
2021
·Vol. 9
·期 19
·2100337
·
IF 9.926
Dan Zhang,Xiangting Zhang,Baofeng Zheng,Qi Sun,Zhibo Zheng,Zhan Shi,Yanhua Song,Haifeng Zou
A series of Eu 2+ single doped Ca 9 Na 1– x Li x Sc 0.667 (PO 4 ) 7 phosphors with full-spectrum emission have been synthesized. Under the 385 nm excitation, the Eu 2+ single doped Ca 9 NaSc 0.667 (PO 4 ) 7 without Li + doping displays a broad cold white light emission with the peaks at about 480 and 610 nm. With the introduction of Li + ions, the Eu 2+ ions selectively occupy the Ca1, Ca2/Ca3, and Na sites. The variation of local environment of Eu 2+ ions caused by Li + ions enhances the luminous intensity, solves the problem of the lack of a red light component, and realizes the emission color tuning from cold white via warm white to orange. A special charge compensation method caused by Li + migration avoids the generation of defects and is beneficial to the improvement of luminescence properties. Eventually, a warm white light-emitting diode device is prepared by combining the white emitting Ca 9 Na 0.8 Li 0.2 Sc 0.667 (PO 4 ) 7 :2%Eu 2+ phosphors with 385 nm LED chip, which exhibits a high color-rendering of 92.9, low correlated color temperatures of 4529 K, and excellent color stability under working temperature. The as-reported warm white emitting Eu 2+ -doped phosphors have potential applications in full-spectrum solid-state lighting. The site engineering strategy provides an extensive guide for optimizing and designing novel single-composition white-emitting phosphor materials.
研究领域:
材料科学
·
光学工程
·
固态照明
✓ 已验证
DOI
高影响因子
Materials Advances
·
2022
·Vol. 3
·期 16
·6529-6538
·
IF 0
Shuqin Chang,Jipeng Fu,Kaina Wang,Xuan Sun,Yingying Ma,Guangcan Bai,Guoquan Liu,Yonggang Wang,Mingxue Tang
Although near-infrared phosphors have been widely reported, discovering efficient red-emitting phosphor materials with superior photophysical properties and high color quality is still a challenge for optimizing white light-emitting diodes (wLEDs). In this regard, a series of Eu2+ and Ce3+ doped SrS phosphors were synthesized via a one-step solid-state method at 1100 °C. The SrS:(Eu2+)n and SrS:(Ce3+)0.01,(Eu2+)n powders show substantial spectral broadening (∼80 nm) along with a significant thermal quenching resistance. The phosphor of SrS:(Eu2+)0.002 exhibits the most intense luminescence with a high color purity of 99.94% and an afterglow luminescence lasting several seconds. The luminescence intensity and peak position were modulated by the resonance-type energy transfer from Ce3+ to Eu2+ ions, which is proposed to follow the dipole–dipole interaction mechanism by Dexter's energy transfer theory and Reisfeld's approximation. The outstanding photoluminescence properties of Eu2+ are attributed to the nephelauxetic effect and crystal field splitting of rock-salt. The wLED device of SrS:(Eu2+)0.05 packaged with a blue chip and (Sr,Ba)2SiO4:Eu2+ shows a super-high color rendering index of 87.9, suggesting great potential for superior luminescence and promising wide applications.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
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