MATERIALS RESEARCH BULLETIN
·
2018
·
IF 2.873
Ming Gu,Yue Tian,Cai’e Cui,Ping Huang,Lei Wang,Qiufeng Shi
A novel red-emitting Ba 2 ZrF 8 : Mn 4+ phosphor was prepared by two-step method at low temperature, where critical precursor K 2 MnF 6 was prepared first by the reduction of KMnO 4 using H 2 O2 as reducer. The crystal structure and morphology of the phosphor was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS), showing single phase product. Luminescent properties of the phosphor were investigated by photoluminescence spectroscopy (PL) and decay curves. The molar ratio of KMnO 4 : KHF 2 was confirmed to play the key role in improving the luminous efficiency. More importantly, the phosphor exhibits a broadband excitation from 300 to 520 nm due to 4 A 2g → 4 T 1g and 4 A 2g → 4 T 2g transition of Mn 4+ , matching well with blue LED chips. Under 465 nm excitation, intense red emission at around 630 nm with high color purity is achieved, suggesting the red-emitting phosphor has great potential for white light-emitting diodes (wLEDs).
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 79
·50396-50402
·
IF 3.108
Shijie Qiu,Hengwei Wei,Mengmeng Wang,Shuai Zhang,Yang Zhou,Ling Xu,Xiaoming Wang,Huan Jiao
A novel ternary-alkaline red emitting fluoride phosphor K2NaGaF6:Mn4+ was successfully synthesized through co-precipitation method. The crystal structure, morphology, electronic band structure and luminescence properties of K2NaGaF6:Mn4+ phosphors were investigated in details by using Rietveld refinement of X-ray diffraction data, scanning electron microscopy (SEM), density functional theory (DFT) calculation and different reaction parameters. The K2NaGaF6 host has a cubic unit cell with the space group Fmm and lattice parameters of a = 8.2577 (4) Å, Z = 4, Vcell = 563.08 (8) Å3. Under blue light excitation, Mn4+ activated K2NaGaF6 exhibits a bright narrow-band red emission. The PL properties of the K2NaGaF6:Mn4+ red phosphors were optimized with different Mn4+ concentrations and aging times. A warm-white LED device was fabricated using a blue LED chip combined with commercial yellow YAG:Ce3+ phosphor and synthesized K2NaGaF6:Mn4+ red phosphor. The color rendering index (CRI, Ra = 81.6) and corresponding color temperature (CCT = 3643 K) easily reached the commercial warm white light LED standards (Ra > 80 and CCT < 4000 K). All these results indicate that K2NaGaF6:Mn4+ phosphor would be a suitable red phosphor candidate for warm-white LED applications.
研究领域:
材料科学
·
光学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2021
·
IF 3.599
Renping Cao,Yanshu Zhao,Zuofu Hu,Wenhua Shao,Fen Xiao,Guotai Zheng,Pan Liu,Ting Chen
In this work, we successfully synthesize La(Mg 1-x Nb x )O 3 :Mn 4+ ( x = 0.296 and 0.384) deep-red emitting phosphors by using high-temperature solid state method in air and investigate their crystal structures, morphologies, and luminescence properties. A broad excitation spectral band of La(Mg 1-x Nb x )O 3 :Mn 4+ phosphors monitored at 705 nm can be observed in the region from 220 nm to 580 nm. La(Mg 1-x Nb x )O 3 :Mn 4+ phosphors show a deep-red emission in the range of 640–760 nm with a peak at ~705 nm due to 2 E → 4 A 2 transition of Mn 4+ ions and the corresponding chromaticity coordinates are (0.7316, 0.22684). The concentration dependent emission spectra indicate that their optimal Mn 4+ doping concentration is ~0.6 mol%. Their lifetime values decrease with increasing the Mn 4+ doping concentration from 0.2 mol% to 1.0 mol%. The experimental results are helpful for the research on luminescence property of Mn 4+ ions.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Communications
·
2022
·
IF 3.662
Bingjie Han,Xinghua Yang,Yuhan Jiang,Zhiang Li,Yu Shen,Xinyu Chang,Jing Ren,Shuai Gao
Nowadays, more and more attention has been paid to artificial lighting sources for plant growth. In this paper, transition metal Mn 4+ activated CaGdMgNbO 6 (CGMNO:Mn 4+ ) red phosphor was prepared high temperature solid state method. The crystal structure and cell parameters of novel CGMNO host were analyzed. The experimental results indicated that CGMNO:Mn 4+ phosphor exhibit an emission band (701 nm), which belongs to the 2 E g → 4 A 2g transition of Mn 4+ . The concentration quenching occurs when Mn 4+ doping concentration is greater than 0.5 mol%. The variable temperature emission spectra proved that the emission intensity of CGMNO:0.005Mn 4+ at 423 K maintained 75.2 % of that at 298 K. The CIE color coordinates and IQE of CGMNO:0.005Mn 4+ are (0.7136, 0.2863) and 49.45 %, respectively. Finally, a LED device was packaged with CGMNO:0.005Mn 4+ phosphor and a high-power chip (440 nm), the LED device shows stable electroluminescence intensity under different currents driving. All the results indicate that phosphors are suitable for lighting contemporary plant growth.
研究领域:
材料科学
·
植物学
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2021
·
IF 5.165
Zhaowu Wang,Xiuyuan Wang,Haipeng Ji,Jian Xu,Zongtao Zhang,Deliang Chen
Due to the low solubility of BaF2, the BaTiF6:Mn4+ phosphor for whitelight-emitting diodes application has been generally synthesized by the hydrothermal route, during which process the valence of the manganese dopant is difficult to be controlled as tetravalent. In this paper, a new synthesis method that proceeded at room temperature was reported. This method uses BaTiOF4 as the precursor and allows for the control of the phase transformation rate from BaTiOF4 to BaTiF6 in the K2MnF6/HF acid solution. Benefitting from that, we successfully prepared red-emitting BaTiF6:Mn4+ elongated crystals with a single-crystal nature up to a record-breaking length of 200–300 μm. The effects of the crystallinity of the BaTiOF4 precursor on its phase transformation rate into BaTiF6 and on the optimal Mn4+ doping concentration were studied. The BaTiF6:Mn4+ single-crystal phosphor exhibits relatively excellent hydrolysis-resistant behavior after being immersed in water for 3 h, at which condition the commercial K2SiF6:Mn4+ has become brown. This study may inspire the room-temperature preparation of other hydrolysis-resistant alkali earth fluorotitanate or fluorosilicate phosphors with stable tetravalent manganese doping.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2018
·Vol. 47
·期 16
·5614-5621
·
IF 4.099
Luqing Xi,Yuexiao Pan,Shaoming Huang,Hongzhou Lian,Jun Lin
Herein, a novel red phosphor based on seven-coordinated Mn4+ ion-doped tridecafluorodizirconate, Na5Zr2F13 (NZF), has been synthesized by stirring a mixture of K2MnF6, NaF, and H2ZrF6 at room temperature. The crystal structure and morphology of the as-obtained phosphor NZF:Mn have been determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The composition and distribution of Mn4+ ions in NZF have been confirmed by energy-dispersive spectroscopy (EDS) and element mapping via transmission electron microscopy (TEM). The phosphor NZF:Mn exhibits a strong zero phonon line (ZPL) at 616 nm under excitation of blue light from a GaN light-emitting diode (LED) chip; this is attributed to the low symmetry of Mn4+ ions occupied in a seven-coordinated environment. The luminescence intensity of NZF:Mn has been optimized by controlling the synthesis procedure and synthetic parameters. The luminescence mechanism of the red phosphor NZF:Mn has been investigated according to the detailed experimental results. A warm white light has been produced by a WLED fabricated with the red phosphor NZF:Mn and the commercial yellow phosphor Y3Al5O12:Ce3+ (YAG:Ce) on a GaN LED chip.
研究领域:
材料科学
·
无机化学
·
发光材料
·
固态照明
·
晶体化学
✓ 已验证
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2023
·
IF 5.4
Xixiang Pan,Di Wu,Songbin Liu,Qiang Zhou,Biqing Song,Lu Wen,Li Luo,Jie Wang,Xinyu Ye
Recently, Mn 4+ doped fluoride phosphors have been considered as ideal candidate materials employed in white light-emitting diodes (WLEDs). However, the extremely serious performance deterioration in a wet environment has affected their practical commercial applications. Herein, we developed a novel thiourea loading strategy for greatly improving the moisture resistance of typical K 2 SiF 6 : Mn 4+ (KSF) red phosphors through treated by thiourea ethanol solution evaporation. The luminescent properties and moisture resistance have been discussed in detail, and the underlying moisture resistance mechanism was further proposed. The results show that the moisture resistance of KSF phosphor treated by thiourea significantly increased approximately sevenfold than that of untreated counterpart, exhibiting a potential application in the WLEDs backlight with high gamut display. These works brings up a promising alternative strategy for enhancing moisture resistance and provides a deeper understanding on the performance degradation mechanism for a variety of Mn 4+ doped fluoride phosphors system.
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 LUMINESCENCE
·
2022
·
IF 4.171
Yi Zhang,Cuiping Zhou,Qifeng Zhang,Pengfei Yin,Xiyuan Sun,Kaiming Wang,Jian Wang,Xing Feng
In this paper, a synthesized material change from perovskite-layer-structured La 2 Ti 2 O 7 to perovskite type LaTiO 3 induced by Li 2 CO 3 addition was observed. The [TiO 6 ] octahedral site symmetry and particle uniformity showed an obvious variation with the change from La 2 Ti 2 O 7 to LaTiO 3 . A broadband far-red emission from 670 to 780 nm emerged when Mn 4+ , Li + ions were co-doped. Furthermore, (Mn 4+ , Li + ) co-doped LaTiO 3 phosphor can be effectively excited by near-UV and blue lights, which is suitable for combining with commercial InGaN LED chips. The LaTiO 3 :0.4%Mn 4+ , 150%Li + phosphor exhibited a high quantum efficiency of 71.1% and a good thermal stability with emission intensity retained 65% at 423 K. Finally, a LED device was fabricated with the LaTiO 3 :0.4%Mn 4+ , 150%Li + phosphor, which matches well with the absorption of photochrome of P FR and shows a good potential for use in agricultural cultivation fields.
研究领域:
材料科学
·
农业科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2016
·
IF 3.014
Cheng Yang,Zhongfang Zhang,Guangcai Hu,Rui Cao,Xiaojuan Liang,Weidong Xiang
Currently, the non-rare-earth Mn 4+ -activated oxide red phosphor is of great interest as color converter for warm white light-emitting diodes (W-LEDs), owing to its admirable luminescent properties and low price. Herein, a novel blue-light activated Ca 14 Zn 6 Ga 10 O 35 :Mn 4+ (CZG:Mn 4+ ) phosphor, exhibiting strong red emission attributed to Mn 4+ : 2 E g → 4 A 2g spin-forbidden transition in region of 650–750 nm under 462 nm excitation, is successfully synthesized through a traditional solid-state reaction route in air. Subsequently, the microstructure and luminescent performance of this red-emitting phosphor are discussed in detail. The crystal field strength ( Dq ) and the Racah parameters ( B and C ) are carefully calculated to estimate the nephelauxetic effect of Mn 4+ suffering from the CZG host lattice. In addition, the concentration quenching and thermal quenching characteristics are also systematically investigated. After incorporating CZG:Mn 4+ and commercial Y 3 Al 5 O 12 :Ce 3+ (Ce:YAG) phosphors into a blue LED device, warm white light with high color rendering index and low correlated color temperature is successfully achieved. Therefore, the CZG:Mn 4+ phosphor can serve as color converter for use in warm W-LED 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
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2020
·Vol. 103
·期 12
·6901-6912
·
IF 3.502
Qiyun Wu,Chenxing Liao,Jinquan Pan,Xinyu Ye,Weixiong You,Libin Xia
It has been one of the hot issues to prepare the red-emitting Mn 4+ -doped fluoride phosphors with highly efficient and waterproofness for warm white-light-emitting diodes (WLEDs) by the green and environmentally friendly method. Herein, we design a novel green molten salt route to synthesize K 2 SiF 6 :Mn 4+ red powder using molten NH 4 HF 2 salt instead of HF liquor as the reaction medium. The results show that KMnO 4 and MnF 2 could produce Mn 4+ in NH 4 HF 2 molten salt through a reduction reaction, and the resulting Mn 4+ -doped K 2 SiF 6 exhibited a bright red emission peaked at 632 nm under blue light excitation. The luminescence intensity of the as-obtained product after immersing into water for 24 hours maintain nearly 100% of that before soaking and emission peak shape remains unchanged. The thermal stability of the sample was evaluated by temperature-dependent luminescence spectral intensity during heating and cooling. Furthermore, a warm white-light-emitting diodes (WLEDs) with an excellent color rendering index (Ra = 87.1), lower correlated color temperature (CCT = 3536K), and high luminous efficacy (116.99 lm·W −1 ) was fabricated based on blue chip and K 2 SiF 6 :Mn 4+ and commercial yellow phosphor (Y 3 Al 5 O 12 :Ce 3+ ).
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2020
·Vol. 8
·期 18
·6299-6305
·
IF 7.059
Xinlong Dong,Yuexiao Pan,Yajun Jia,Rongjing Liu,Hongzhou Lian,Jun Lin
Mn4+-activated red phosphors have recently attracted tremendous attention for their fascinating performance in white light emitting diode (WLED) applications, achieving warm white light, while the thermal stability of fluorides is still considered as a drawback. Herein, we report a novel red phosphor composed of Ba3Sc2F12:Mn4+ (BSF:Mn), in which the emitting centers of Mn4+ ions are located in the sites of Sc3+ ions. The photoluminescence of BSF:Mn varies with the concentration of K2MnF6, reaction temperature, and the concentrations of NH3·H2O in the reaction system. Partly substituting Ba2+ with Ca2+ decreases the luminescence intensity of BSF:Mn. By employing the as-prepared phosphor BSF:Mn as a red component, a high-performance WLED with a correlated color temperature (CCT) of 4796 K and a color rendering index (CRI) of 85.2 was obtained. The phosphor BSF:Mn remains undecomposed up to 800 °C; therefore, this work provides a strategy to explore a novel Mn4+-doped fluoride with particularly good thermal stability.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2023
·Vol. 52
·期 17
·5587-5596
·
IF 4
Zhijian Liao,Yan Li,Jiaxing Zuo,Guang Chen,Heng Liang,Shihao Wu,Jiaqing Peng,Xinyu Ye
For high-efficiency lighting and wide color gamut backlight display, high-quality narrow-band red phosphors for WLEDs are still in high demand. Herein, a novel red-emitting fluoride phosphor Cs2NaGaF6:Mn4+ was successfully synthesized by a simple two-step co-precipitation method and exhibits ultra-intense zero-phonon lines (ZPLs) and long wavelength phonon sidebands under 468 nm blue light irradiation. The ZPL emission peak of Cs2NaGaF6:Mn4+ was located at 627 nm, which is much stronger than its υ6 vibration peak, more matchable with the eye-sensitive region of humans, and beneficial for obtaining higher luminous efficiency of WLEDs. Interestingly, the υ6 vibration peak of this red phosphor is at 636.5 nm, which is larger than that of the common fluoride phosphor A2BF6:Mn4+ (usually at about 630 nm, represented by K2SiF6:Mn4+) at about 6.5 nm. Thanks to the longer wavelength of the υ6 vibration peak, the chromaticity coordinates (0.7026, 0.2910) with a larger x-coordinate value were realized, leading to a potentially wider color gamut of WLEDs. In addition, this phosphor has high thermal stability and its emission intensity at 423 K remains 93.7% of the initial intensity at room temperature. The lumen efficiency of WLED1 packaged with a mixture of Cs2NaGaF6:Mn4+ and YAG:Ce3+ on the InGaN blue chip is 115.7 lm W−1 with the color temperature (Tc) = 3390 K and the colour rendering index (Ra) = 92.5 under 20 mA driving current. The chromaticity coordinates of WLED2 packaged with Cs2NaGaF6:Mn4+ and β-SiAlON:Eu2+ on the InGaN blue chip are (0.3149, 0.3262) and the calculated color gamut is up to 118.4% (NTSC). These results indicate that Cs2NaGaF6:Mn4+ red phosphors have promising applications in the high-quality lighting and display fields.
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
危险品化学品经营许可证（带存储）