SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2013
·
IF 1.977
Renping Cao,Kaniyarakkal N. Sharafudeen,Jianrong Qiu
Red-emitting SrMgAl x O 17±δ : y Mn 4+ composite phosphors ( x = 10–100; y = 0.05–4.0 mol%) are synthesized by solid-state reaction method in air. Addition of Al 2 O 3 leads to the formation of two concomitant phases, i.e., SrMgAl 10 O 17 and Al 2 O 3 phases in the composite phosphor. Red emission from Mn 4+ ions in the composite phosphors is greatly enhanced due to multiple scattering and absorption of excitation light between SrMgAl 10 O 17 and Al 2 O 3 phases. SrMgAl x O 17±δ : y Mn 4+ composite phosphors would be a promising candidate as red phosphor in the application of a 397 nm near UV-based W-LED.
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
·
2016
·Vol. 4
·期 8
·1675-1684
·
IF 5.066
M. Wu,E. H. Song,Z. T. Chen,S. Ding,S. Ye,J. J. Zhou,S. Q. Xu,Q. Y. Zhang
Single-band red upconversion (UC) emission of Er3+ has been successfully achieved in Yb3+/Er3+ codoped KMgF3 nanocrystals via a nonequivalent substitution strategy, in which lanthanide ions probably aggregate, as evidenced by density functional theory calculations and upconversion dynamic processes. The aggregation of Yb3+/Er3+ would cause large cross-relaxation probabilities among the lanthanide ions when photo-excited, resulting in the disappearance of the green emission and the population of the red emitting level of Er3+. Interestingly, the single-band feature is independent of the dopant concentration and pump power. The possible UC mechanism is discussed in detail according to nanocrystal morphology, ion radii, lattice parameters and decay lifetime studies of the Yb3+–Er3+ doped analogous compounds (KMgF3, KZnF3 and KCdF3). It could be concluded that Yb3+/Er3+ ions tend to aggregate in KMgF3, resulting in the largest ratio of red to green UC emission. This research may give a perspective toward tuning the UC emission of lanthanide ions.
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 SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 6
·7026-7033
·
IF 2.478
Shen Menghan,Cheng Zhiyuan,Li Yongjin,Liu Tong,Peng Yan,Zhang Yueli
The single-band red upconversion (UC) emission of lanthanide-doped materials have attracted attention due to its great potential for versatile applications. In this work, YbOCl: x Er 3+ with super pure red UC emission had been successfully synthesized by conventional high temperature solid-state reaction. X-ray powder diffraction (XRD) confirmed the rhombohedral structure with space group R -3 m (166). Scanning electron microscopy (SEM) exhibited agglomeration morphology of smooth sheets with nanometer thickness. The UC emission spectra of YbOCl:Er 3+ manifested intense red emission and much lower green emission when pumped by 980 nm diode laser. The dominating red emission peaking at 670 nm was assigned to the electron transition 4 F 9/2 → 4 I 15/2 . The green emission at 521 nm and 547 nm were corresponding to 2 H 11/2 → 4 I 15/2 and 4 S 3/2 → 4 I 15/2 transition of Er 3+ , respectively. The CIE chromaticity coordinates showed the color of samples lain in red region and the purity of red emission could be tuned by the concentration of Er 3+ . The UC luminescence mechanism was proposed based on the relationship of UC intensity versus pump power density and their lifetime. Our research provided a new thought for realizing single-band red emission without any further modification.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
LUMINESCENCE
·
2018
·Vol. 33
·期 2
·438-442
·
IF 1.671
Ting Li,Zhijun Wang,Panlai Li,Shuchao Xu,Qiongyu Bai,Zhiping Yang
A novel tunable red emitting phosphor LiBaB 9 O 15 :Sm 2+ /Sm 3+ , Li + with broad excitation band was synthesized by a high temperature solid-state method. Luminescence properties were investigated in detail by luminescence, X-ray photoelectron spectroscopy (XPS) spectra and CIE chromaticity coordinates. XPS data confirmed that there were Sm 3+ in LiBaB 9 O 15 :Sm 3+ and Sm 2+ /Sm 3+ in LiBaB 9 O 15 :Sm 2+ /Sm 3+ , respectively. Spectral property of LiBaB 9 O 15 :Sm 3+ , LiBaB 9 O 15 :Sm 3+ /Sm 2+ and LiBaB 9 O 15 :Sm 2+ , Li + presented that the excitation band of Sm 3+ widened and the excitation band of Sm 2+ ranged from 350 to 450 nm. And the red light color is tunable with changing Li + concentration. The results indicated that LiBaB 9 O 15 :Sm 2+ /Sm 3+ , Li + may be promising red phosphor for white light emitting diodes.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 51
·29533-29540
·
IF 3.049
Dan Zhao,Xuemei Liu,Chunjin Wei,Yimo Qu,Xincai Xiao,Han Cheng
The synthesis of carbon dots (CDs) with long wavelengths, particularly the red-emitting ones, has always been the focus of researchers, and a carbon source is critical in this process. In this study, we report the synthesis of red-emitting CDs (CD-tetra) via a one-step solvothermal method with 1,2,4,5-benzenetetramine tetrahydrochloride as a novel carbon source and ethanol as a solvent, and the quantum yield (QY) of CDs is as high as 30.2%. Middle chromatography isolated gel (MCI Gel) column was used to obtain R-CDs, O-CDs and Y-CDs with emission wavelengths at 619, 608 and 554 nm, respectively. It was discovered that these CDs exhibited great differences in their particle sizes and elemental compositions. Moreover, the fluorescence of the CD-tetra could be efficiently quenched using methylene blue (MB). Under optimal conditions, a linear relationship between the decreased fluorescence intensity of the CD-tetra and the concentration of MB was established in the range of 0.05–9.5 μM. The limit of detection (LOD) is 10 nM, suggesting a promising assay for the detection of MB.
研究领域:
材料科学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry C
·
2017
·Vol. 5
·期 34
·8828-8835
·
IF 5.256
Yibo Chen,Kuanglun Wu,Jin He,Zhengbin Tang,Jianxin Shi,Yiqin Xu,Zhao-Qing Liu
The rational and delicate synthesis of Mn4+ activated red-emitting oxide phosphors with high photoluminescence quantum yield (PLQY) and photo-stability for developing high-quality w-LEDs still remains a great challenge. Herein, we demonstrate a simultaneous ion co-substitution design strategy to synthesize a red-emitting Lu3Al5O12:Mn4+,Mg2+ garnet phosphor delicately with the assistance of MgF2. The Mn4+ activated garnet phosphor exhibits superior moisture resistance properties and high PLQY (ca. 72.41%), which emits a bright and narrow-band red light peaking at ∼670 nm due to the 2E–4A2 spin-forbidden transition of Mn4+ upon UV excitation. Remarkably, MgF2 as a charge compensator & flux can not only accelerate the solid state reaction, but also greatly improve the emission intensity. Furthermore, by employing the as-prepared Lu3Al5O12:Mn4+,Mg2+ as a red component, we fabricate a warm w-LED with a high color rendering index (Ra = 81.4) and low color temperature (CCT = 4766 K) based on a UV chip and commercial blue and yellow phosphors.
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
·
2020
·
IF 3.28
Xiaokai Xu,Lifeng Cai,Guangqi Hu,Luoqi Mo,Yihao Zheng,Chaofan Hu,Bingfu Lei,Xuejie Zhang,Yingliang Liu,Jianle Zhuang
As a new type of carbon nanomaterial , carbon dots (CDs) have attracted more and more attention due to their excellent properties. Here, we developed a simple, green and environmentally friendly method for preparing red-emissive CDs from spinach. The emission color of the CDs under UV light changed from red luminescence to green luminescence after one to four weeks. This was due to the change of the aggregated molecules on the surface of CDs. It was demonstrated that the nitrogen content of the CDs gradually decreased with the increase of time, since CDs combined with oxygen to form aggregates to eliminate excess nitrogen. It was further found that CDs showed the increase intensity of the emission in 500 nm wavelength and decrease intensity of the emission in 665 nm wavelength, which could be attributed to their respective emission from different molecular structures. Compared with the CDs stored for one week, the agglomeration of the CDs particles after four weeks was obvious, indicating that its light stability depended on the agglomeration structure of CDs. Due to their special properties, the CDs could be used for visual detection of time.
研究领域:
材料科学
·
环境科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 37
·12658-12666
·
IF 6.4
Qiao Qu,Konglan Chen,Yayun Zhou,Jinsheng Li,Haipeng Ji
A K2SiF6:Mn4+ phosphor with narrow line-type red emission plays an important role in white light-emitting diode (WLED) backlights for liquid crystal displays, but this phosphor exhibits weak zero phonon line (ZPL) emission. The ZPL intensity of the Mn4+ 2Eg → 4A2g transition can be enhanced after relaxing the orbital selection rule. We dope Mn4+ into a host lattice with mixed-anions to introduce a distortion of local coordination octahedra around Mn4+ and relax the orbital selection rule. Remarkably, the Na2MoO2F4:Mn4+ phosphor with [MoO2F4] mixed-anion coordination exhibits a dominant luminescence peak at 625 nm (ascribed to the ZPL) and the ZPL to Stokes v6 intensity ratio reaches an unprecedented high value of 243% under 480 nm excitation. Density functional theory calculations indicate that the most energy-efficient pathway for maintaining charge balance during Mn4+-doping involves the substitution of [MoO2F4]2− by [MnF6]2−, which generates a strong crystal field with a high Dq/B value of 4.05 for Mn4+ in Na2MoO2F4. An optimal composition Na2MoO2F4:1.5%Mn4+ (nominal) exhibits a high color purity of 99.3% and a short luminescence lifetime of 0.62 ms, suggesting its potential in fast-response backlight display applications. When incorporated into WLEDs, the red-emitting Na2MoO2F4:Mn4+ phosphor contributes to a broad color gamut (∼108.3% NTSC). Comparative analysis of a series of Mo6+-based oxyfluoride phosphors demonstrates that Mn4+ more readily exhibits intense ZPL and fast luminescence decay occurs when Mo6+ is coordinated in an O/F ordered octahedron.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
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
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 102
·期 10
·5910-5918
·
IF 3.094
Renping Cao,Xinyan Lv,Yaqin Ran,Longxiang Xu,Ting Chen,Siling Guo,Hui Ao,Xiaoguang Yu
Li 5 La 3 Ta 2 O 12 :Mn 4+ (LLTO:Mn 4+ ) phosphors are prepared in air via high-temperature solid-state method and investigated for their crystal structures and luminescence properties. LLTO:Mn 4+ phosphor under excitation at 314 nm shows deep-red emission peaking at 714 nm due to the 2 E→ 4 A 2 transition of Mn 4+ ion. The excitation bands in the range 220 - 570 nm are attributed to the Mn 4+ - O 2- charge-transfer band and the 4 A 2g → 4 T 1g , 2 T 2g , and 4 T 2g transitions of Mn 4+ , respectively. The optimal Mn 4+ ion concentration is ~0.4 mol%. The concentration quenching mechanism in LLTO:Mn 4+ phosphor is electric dipole-dipole interaction. The luminous mechanism and temperature quenching phenomenon are explained by the Tanabe-Sugano energy level diagram and the configurational coordinate diagram of Mn 4+ in the octahedron, respectively. The experimental results indicate that LLTO:Mn 4+ phosphor has a potential application prospect as candidate of deep-red component in light-emitting diode (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
OPTIK
·
2021
·
IF 2.443
Kai Ye,Xiaoliang Yang,Siguo Xiao
Bi 3+ , Mn 2+ co-doped CaZnGe 2 O 6 red long afterglow materials were prepared by high temperature solid state reaction method. The phosphor has broad excitation band ranging from 220 nm to 350 nm with two peaks at 255 nm and 300 nm and can give blue, green and red emission band peaking at 448 nm, 530 nm and 645 nm, respectively. Due to the emission properties of Bi 3+ ions and the Bi 3+ →Mn 2+ energy transfer, the co-doped Bi 3+ ions can not only enhance the PL luminescence of the phosphor, but also adjust the emission color. After irradiation of 300 nm ultraviolet light , the phosphors exhibits long-persistent red phosphorescence. Thermoluminescence tests demonstrate that the introduction of Bi 3+ ions can increase the trap depth and trap concentration, greatly improving the afterglow time and brightness of the CaZnGe 2 O 6 : Mn 2+ phosphor. The present work might provide reference for designing new rare earth free red long afterglow materials.
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 ALLOYS AND COMPOUNDS
·
2016
·
IF 3.014
Zheng-Bin Tang,Cai-Li Xu,Xun-Rong Wei,Xin-Guo Zhang,Yi-Bo Chen
Developing high brightness, high color purity and thermal stable red phosphors has gained an increasing attention for enhancing the performance of white light emitting diodes (w-LEDs). Herein, a series of red-emitting KBaY 1−x Eu x Si 2 O 7 (0 < x < 1) solid-solution phosphors were designed and fabricated. The phosphors can be excited by 394 nm near-UV light and emit red light peaking at 612 nm due to the 5 D 0 → 7 F 2 transition of Eu 3+ . The increasing proportion of Eu 3+ in the solid-solution system can improve the photoluminescence intensity and thermal stability of the phosphors continuously until the Eu 3+ concentration comes to 100%, while no deformation of the crystal structure has been brought. The as-prepared KBaEuSi 2 O 7 phosphor shows excellent thermal photoluminescence stability, its emission integrated intensity can still maintain ∼90% of the initial value at room temperature when heating to 180 °C. The CIE coordinates (0.652, 0.348) of KBaEuSi 2 O 7 phosphor are very close to the NTSC (National television system committee) standard red chromaticity (0.67, 0.33), and the color shift at high temperature is very slight. The KBaEuSi 2 O 7 phosphor can be regarded as a promising red luminescence candidate for w-LEDs.
研究领域:
材料科学
·
光学
✓ 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）