JOURNAL OF LUMINESCENCE
·
2020
·
IF 3.28
Shijie Qiu,Hengwei Wei,Xiaoming Wang,Shuai Zhang,Mengmeng Wang,Yiying Wang,Ling Xu,Huan Jiao
A series of efficient red phosphors, K 2 SiF 6 :Mn 4+ (KSFM) particles with highly regular, uniform and anisotropic shapes, were successfully prepared by a two-step chemical co-precipitation method at room temperature without using surfactant and template. A morphological map for KSFM particles with five distinctive shapes was depicted by adjusting KF-HF precipitator dropping speed. Moreover, the photoluminescence , decay curves and Raman spectral dependence of the KSFM phosphors with different morphologies were investigated. Luminescence intensity of the KSFM phosphors is highly correlated with the morphology of KSFM particles, which gradually increased as the particle shapes changed from cube to octahedron . Whereas, Raman spectra and flame atomic absorption spectrophotometer results indicated that Mn 4+ concentration in a series of KSFM particles decreased gradually. Growth mechanism of particle is discussed base on reticular density and surface energy. White LED devices made of a blue GaN chip merged with yellow phosphor (YAG: Ce 3+ ) and the obtained KSFM red phosphor could produce warm white light. Drive current testing of the fabricated w-LEDs proved the KSFM phosphor in octahedron shape is more stable than that of the KSFM in cubic shape.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2019
·
IF 2.961
V. Naresh,Nohyun Lee
Mn 4+ -activated KGaP 2 O 7 red emitting phosphor was successfully synthesized via traditional solid-state reaction method in air. The structural features of KGaP 2 O 7 : x Mn 4+ material were investigated by means of powder XRD & Raman, morphology from SEM, and element analysis , corresponding mapping through EDAX . In conjunction, concentration and temperature dependent spectroscopic properties were analyzed from UV–Vis reflectance, excitation, emission and lifetime decay curves. Powder XRD and photoluminescence profiles revealed that GaO 6 polyhedra offer Mn 4+ ions to substitute the Ga 3+ sites in the crystal lattice resulting in a pure single phase structure with an efficient red emission at 702 nm (Mn 4+ : 2 E g → 4 A 2g ) under 452 nm excitation. The emission decay curves exhibited non-exponential nature with lifetimes shortening when Mn 4+ concentration is increased. Electric dipole-dipole interaction is identified to be responsible for the concentration quenching beyond 0.07 Mn 4+ via energy transfer between Mn 4+ ions. The temperature-dependent emission intensity for KGaP 2 O 7 :0.07Mn 4+ exhibited 66% at 423 K (150 °C) displaying good thermal stability and activation energy ( E a ) of ∼0.186 eV. From UV–Vis reflectance spectra using Tanabe-Sugano diagram, crystal splitting factor ( Dq ), two Racah parameters (B & C) , Dq/B , C/B and energy of states are calculated to evaluate nephelauxetic ratio ( β ). In addition, the effect of Mn 4+ content (concentration quenching) and temperature (thermal quenching) on emission intensity are discussed based on the Tanabe-Sugano energy diagram and configurational coordinate scheme of Mn 4+ . Therefore, KGaP 2 O 7 :Mn 4+ phosphor can serve as a potential red emitting phosphor under blue light excitation and can also be useful to enhance plants growth.
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 Materials Chemistry C
·
2019
·Vol. 7
·期 8
·2401-2407
·
IF 6.641
Yong Liu,Zhi Zhou,Lin Huang,Mikhail G. Brik,Shuaichen Si,Litian Lin,Tongtong Xuan,Hongbin Liang,Jianbei Qiu,Jing Wang
Narrow-band red-emitting fluoride phosphors for wide color gamut LED backlights have evoked considerable attention, due to their fascinating optical properties. Unfortunately, poor moisture resistance often restricts their further applications in optoelectronics. Herein we developed a Cs2SiF6:Mn4+ red phosphor using a low-temperature co-precipitation method and passivating it by using H2O2. The phosphor shows a very high external quantum efficiency (EQE) of ∼85% and exhibits excellent moisture stability retaining 74% of its emission intensity after being exposed to high temperature (85 °C) and high humidity (85%) (HTHH) for 168 h. Finally, the high brightness white LED devices combined with the passivated Cs2SiF6:Mn4+ exhibit high luminous efficacy of 133 lm W−1 and wide color gamut (∼84.7% NTSC). The results demonstrate that the passivated Cs2SiF6:Mn4+ with high EQE and excellent moisture-resistance is promising as a narrow-band red emitting phosphor for wide color gamut LED backlights.
研究领域:
材料科学
·
光电技术
·
光子学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2017
·Vol. 5
·期 36
·9255-9263
·
IF 5.256
Luqing Xi,Yuexiao Pan,Mengmeng Zhu,Hongzhou Lian,Jun Lin
A kind of red-emitting phosphor NaKSnF6:Mn4+ (NKSF:Mn) has been obtained from NaF and KF with a certain molecular ratio in HF solution at room temperature. The phosphor NKSF:Mn exhibits superior optical properties including high color purity with narrow-band emissions as well as better chromaticity coordinates compared to the red phosphors Na2SnF6:Mn4+ (NSF:Mn) and K2SnF6·H2O:Mn4+ (KSFH:Mn). The composition and structure of NKSF:Mn have been identified by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). The formation mechanism of NKSF:Mn is discussed and the morphology, thermal stability, and optical properties of NKSF:Mn have been investigated. The luminescence intensity of NKSF:Mn has been improved by optimizing synthetic parameters. A white light-emitting diode (WLED) fabricated using a blue GaN chip, a yellow YAG:Ce phosphor, and the as-prepared red phosphor NKSF:Mn exhibits superior warm white light with a color rendering index (CRI) of 90.3 at a correlated color temperature (CCT) of 3746 K.
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
·
2015
·
IF 2.605
Renping Cao,Qingqiang Xiong,Wenjie Luo,Donglan Wu,Xiao Fen,Xiaoguang Yu
A series of SrAl [4−(4 x )/3] O 7 : x Mn 4+ (0≤ x ≤1.4 mol%) and Sr (1−0.06/2) Al [4−(4×0.008)/3] O 7 :0.008Mn 4+ ,0.06R + (R + =Li + , Na + , and K + ) phosphors are synthesized by a conventional solid-state reaction method in air. The PLE bands peaking at~325, 395, and 470 nm and the strongest PL band peaking at~660 nm are assigned to the 4 A 2 → 4 T 1 transition of Mn 4+ ion and O 2− –Mn 4+ change transfer band, 4 A 2 → 2 T 1 , 4 A 2 → 4 T 2 , and 2 E → 4 A 2 transitions, respectively. The optimum Mn 4+ doping concentration is about 0.8 mol%. Li + , Na + , and K + ions used as charge compensator can improve observably the PL intensity of SrAl 4 O 7 :Mn 4+ phosphor with excitation 325 nm. The fluorescence lifetimes of SrAl [4−(4×0.008)/3] O 7 :0.008Mn 4+ and Sr [1−0.06/2] Al [4−(4×0.008)/3] O 7 :0.008Mn 4+ ,0.06 R + (R + =Li + , Na + , and K + ) are 0.958, 0.97, 1.113 and 0.965 ms, respectively. The luminous mechanism is explained by schematic energy level diagram of Mn 4+ ion. These experiment results indicate that SrAl 4 O 7 :Mn 4+ ,R + (R + =Li + , Na + , and K + ) phosphors can be used as red emitting phosphor candidate for white LEDs based on a UV (~325 nm) and near UV (~395 nm) bands of LEDs chip.
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 MOLECULAR STRUCTURE
·
2024
·
IF 4
Renping Cao,Xiaoshan Hu,Jingheng Nie,Bang Lan,JinRong Wang,Ting Chen,Yuyu Chen,Jing Wang
With the need of food safety and high yield, new luminescent materials with promoting plant photosynthesis have attracted more and more attention. In this research, we synthesize the far-red-emitting LaBaMg(Ti 0.5 W 0.5 )O 6 :Mn 4+ phosphor in air. We investigate the crystal structure and phase, particle morphology and size, and the luminescence properties. The samples show a broad excitation spectrum under monitored 704 nm due to the Mn 4+ - O 2− charge transfer (CT) and the transitions 4 A 2g → 4 T 1g , 2 T 2g , and 4 T 2g of Mn 4+ in the range of 300 – 600 nm. The far-red emission of sample is observed with the emission spectrum (650 – 790 nm) is attributed to the E g → 4 A 2g transitions. The chromaticity coordinates are (0.7329, 0.2671). The crystal field strength ( D q ), the Racah parameters ( B and C ), and D q / B values are ∼ 1972 cm −1 , 596 cm −1 , 3219 cm −1 , and 3.31, respectively. 0.2 mol% is the optimal Mn 4+ concentration. Emission spectra under excitation wavelength from 320 nm to 560 nm and time-resolved emission spectra confirm the only luminous center (Mn 4+ ) in LaBaMg(Ti 0.5 W 0.5 )O 6 :Mn 4+ . Lifetime reduces with added Mn 4+ concentration. The temperature-dependence emission spectra confirm that sample has a good thermo-stability. The thermal quenching phenomenon and luminous mechanism are analyzed. The luminescence properties of sample infer its application prospect in plant growth light-emitting diode (LED).
研究领域:
材料科学
·
植物学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Yufan Wei,Qianxing Huang,Shijie Yu,Qiyue Shao,Jianqing Jiang
The K2SiF6:Mn4+ (KSFM) phosphor featuring efficient ultranarrow red emissions is an outstanding candidate for white light-emitting diode (WLED) applications. However, poor moisture resistance seriously affects its application performance. In this study, a two-step surface reconstruction strategy is proposed to dramatically enhance the moisture resistance of commercially available KSFM phosphors, involving treatment with H2NbF7 and subsequent hydrothermal treatment. The modified KSFM phosphor exhibits a high internal quantum efficiency (IQE) of 98.9% after the two-step surface treatment. Meanwhile, nearly 100% of the initial emission intensity is retained for the modified KSFM phosphor even after aging in high temperature (85 °C) and high relative humidity (85% RH) environments for 6 days, in sharp contrast to only 18.6% retention for the original KSFM phosphor. The relative emission intensity of the modified KSFM remains at 98.9% even after being immersed in water for 6 h. Additionally, the phosphor-converted LED fabricated with the modified KSFM phosphor demonstrated excellent long-term stability, retaining up to 97.9% of initial luminous efficacy after aging under 85 °C and 85% RH conditions for 500 h. The moisture-resistance mechanism is elucidated on the basis of spectroscopic analysis as well as structural and compositional characterization of the phosphor surface layer, which can be attributed to the formation of a robust Mn4+-rare shell with high crystalline quality following this two-step surface treatment. The findings contribute to the performance improvements of KSFM phosphors for industrial applications.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 16
·9244-9252
·
IF 3.049
Mao Xia,Simin Gu,Cheng Zhou,Longhai Liu,Yuan Zhong,Yongli Zhang,Zhi Zhou
Plant growth LEDs have attracted broad attention in modern society, desperate for specific phosphors with a characteristic emission band. A novel Mn4+ and Dy3+ co-doped Y3Al4GaO12 phosphor were successfully prepared through a conventional high-temperature solid-state reaction. A three band emission including red (625–700 nm), orange (550–607 nm) and blue (462–490 nm) is observed in these phosphors when excited under a near-UV lamp, which is ascribed to 2E → 4A2 of Mn4+, 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 of Dy3+, respectively. The three emissions match the absorption spectra of chlorophyll A and chlorophyll B well. Meanwhile, the energy transfer from Dy3+ to Mn4+ was confirmed by the luminescence spectra and lifetime analysis. Finally, an LED device was fabricated that consisted of a 365 nm ultraviolet chip and the Y3Al4GaO12:Mn4+,Dy3+ phosphor. The excellent properties indicate that the synthesized phosphor has a promising application in the optical agricultural industry.
研究领域:
材料科学
·
农业光学
·
植物生理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF LUMINESCENCE
·
2022
·
IF 4.171
Xi Zhang,Song Qing,Yi Qin,Qiang Zhou,Jing Wan,Huaijun Tang,Zhenglian Wang
Searching for efficient Mn 4+ red phosphors for white lighting and display backlighting has drawn great attention. In this work, an efficient Mn 4+ -doped fluoroscandate, Rb 2 KScF 6 :Mn 4+ , with short fluorescence lifetime is prepared via a facile co-precipitation method. It was found that the nonequivalent occupation of Mn 4+ for Sc 3+ leads to the identifications of sharp red emissions, enhanced zero-phonon line, high quantum efficiency and short fluorescence lifetime upon blue light excitation. Thanks to the luminescent properties, good optical parameters of high color rendering index, low correlated color temperature, and acceptable color gamut were achieved by coating the red Rb 2 KScF 6 :Mn 4+ phosphor with yellow Y 3 Al 5 O 12 :Ce 3+ or green β -SiAlON:Eu 2+ phosphor in various white light-emitting diodes, demonstrating its potential role for white light illumination and backlight display applications.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2018
·Vol. 47
·期 46
·16516-16523
·
IF 4.099
Lei Zhang,Luqing Xi,Yuexiao Pan,Yajun Jia,Mingmei Wu,Hongzhou Lian,Jun Lin
A series of red-emitting phosphors composed of Li2ZrF6:Mn4+ (LZF:Mn) have been synthesized via an ionic-exchange reaction route at room temperature. The microstructure and optical characterizations have been investigated according to the detailed experiments. The morphology of the phosphor LZF:Mn changes with the concentration of HF, the reaction time and temperature. The uniform crystals of LZF:Mn with regular hexagonal tablets have been obtained in 30–40 wt% HF solutions by conducting the reaction at room temperature for about 8 h. The influences of reaction parameters on the morphology and photoluminescence properties of LZF:Mn have been systematically investigated. The luminescence intensity of LZF:Mn has been optimized by controlling the synthesis procedure and parameters. The white light-emitting diode (WLED) fabricated with LZF:Mn and Y3Al5O12:Ce3+ (YAG:Ce) on InGaN LED chip displays a warm white light with correlated color temperature (CCT) at 3789.4 K and color rendering index (CRI) of 91.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2022
·
IF 3.841
Bang Lan,Renping Cao,Ting Chen,Lan Li,Ru Liu,Xuehua Yi,Shuijing Nie,Jing Wang
LaSrRO 4 :Mn 4+ (R = Al and Ga) are prepared by the high-temperature solid-phase method in air. Their luminescence properties, crystal structure, concentration dependent spectra, time-resolved spectra, fluorescence lifetime, and luminous mechanism are systematically researched, respectively. Mn 4+ ion is the luminescence center of LaSrRO 4 :Mn 4+ (R = Al and Ga). The excitation spectra of LaSrRO 4 :Mn 4+ (R = Al and Ga) under monitored at 715 nm lie in the range 210 – 650 nm with two main excitation peaks at ∼360 nm and 520 nm. With the excitation at 360 and 520 nm, LaSrRO 4 :Mn 4+ (R = Al and Ga) emit far-red light and have the emission spectra covering the region from 650 to 800 nm due to the 2 E g → 4 A 2g transition of Mn 4+ ions. The ideal Mn 4+ concentration in LaSrAlO 4 :Mn 4+ and LaSrGaO 4 :Mn 4+ are ∼ 0.4 mol% and 0.6 mol%, respectively. The spectral properties of samples verify the crystal field s via the Tanabe-Sugano energy level diagram of Mn 4+ ion. LaSrRO 4 :Mn 4+ (R = Al and Ga) have the emission spectra match with the absorption spectra of the plant photosensitive pigments red light and far-red light, which infers their promising application in plant growth light-emitting diode (LED) lamp
研究领域:
材料科学
·
光学
·
植物学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2024
·
IF 5.3
Jun Zheng,Linglin Wang,Lei Feng,Yuhan Gao,Feiyao Ren,Siyu Liu,Ting Zhou,Xiaochun Wu,Xin Lai,Daojiang Gao
Recently, Mn 4+ -activated fluoride red phosphors have received intensive attention due to their excellent luminescence properties. However, poor moisture resistance hinders their commercial application. Herein, (K 1- x Cs x ) 2 NbF 7 :Mn 4+ phosphors were designed and synthesized. All the obtained samples are rod-like microcrystals with monoclinic phase structure, Cs + -doping concentration has little influence on the microstructure while significantly impacts their luminescence properties. Specially, the composition optimized (K 1- x Cs x ) 2 NbF 7 :Mn 4+ ( x = 0.3) phosphor has the color purity of 94.20 %, the quantum yield of 53.90 % and the decay lifetime of 3.59 ms. More importantly, the optimized phosphor can maintain 83.20 % of the initial emission intensity after being immersed in distilled water for 1440 min, showing the excellent moisture resistance. A warm WLED with high CRI of 85 and low CCT of 4362 K is achieved by coating the obtained optimized red phosphor in chip. Our work demonstrates that the (K 1- x Cs x ) 2 NbF 7 :Mn 4+ red phosphors possess a great potential application in warm WLEDs.
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
危险品化学品经营许可证（带存储）