CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Yuanyuan Liu,Jing Gao,Wen Shi,Xuyao Feng,Zijing Zhou,Jianxu Wang,Junlan Guo,Ruyi Kang,Bin Deng,Ruijin Yu
In this study, novel deep-red-emitting Mg 2 InSbO 6 :Mn 4+ phosphors were prepared through a high-temperature solid-state reaction. The as-prepared phosphors belong to the perovskite structure with the space group of R 3 ‾ (No.148). The calculated energy gap value of Mg 2 InSbO 6 is ~1.788 eV. Emission spectrum of the Mg 2 InSbO 6 :0.3%Mn 4+ was obtained under 301 nm excitation, which centered 665 nm due to the 2 E g → 4 A 2g transition. The optimum concentration of Mg 2 InSbO 6 : x Mn 4+ is confirmed to 0.3% mol, and the concentration quenching effect is ascribed to the dipole–dipole interaction. The relative temperature-dependent PL spectra demonstrate that phosphors possess commendable repeatability and high activation energy . The chromaticity shift diagram shows the phosphors have good resistance of color drifting. The Mg 2 InSbO 6 :0.3%Mn 4+ phosphor has a high color purity of 99.8%. Furthermore, a red light-emitting diode is fabricated with Mg 2 InSbO 6 :0.3%Mn 4+ phosphor and a 365 nm near-ultraviolet chip. The emission spectrum of the red LED is perfectly overlapped with plant pigments (chlorophyll a and chlorophyll b ) absorption spectrum . Thus, Mn 4+ -activated Mg 2 InSbO 6 :Mn 4+ phosphors have the potential to apply in plant-cultivation LEDs.
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高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
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2021
·
IF 3.498
Jinsheng Liao,Minghua Wang,Zhuo Han,Junxiang Huang,Guoliang Gong,Junxiang Fu,He-rui Wen
A new far-red/green dual-emitting phosphor La 2 ZnTiO 6 :Mn 4+ /Er 3+ (LZT:Mn 4+ /Er 3+ ) was successfully synthesized by the sol-gel method. Under 381 nm excitation, LZT:Mn 4+ /Er 3+ phosphor shows the strong far-red emission peak of 709 nm (Mn 4+ : 2 E g → 4 A 2g ) and weak green emission peak of 523/548 nm (Er 3+ : 2 H 11/2 / 4 S 3/2 → 4 I 15/2 ), which consistent with the requirement of plant growth for far-red and green light. A 1.5-fold enhancement of far-red emission intensity is found in LZT:Mn 4+ /Er 3+ phosphor compared with the Mn 4+ singly-doped counterparts. Moreover, the relative emission intensity of far-red and green can be easily controlled by changing temperature. Utilizing the optimal LZT:0.2%Mn 4+ /2%Er 3+ phosphor as plant lighting, a prototype near-UV-pumped LED device was fabricated. Upon 120 mA driving current, it demonstrated far-red/green dual emission. All the results indicated that the LZT:Mn 4+ /Er 3+ phosphor is a potential material for plant growth illumination with far-red/green light.
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高影响因子
OPTICAL MATERIALS
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2020
·
IF 2.779
Jinsheng Liao,Minghua Wang,Guoliang Gong,Yijian Sun,Haiping Huang,He-Rui Wen,Chaoyang Tu
In this paper, a novel far-red tantalate phosphor Ca 2 ScTaO 6 :Mn 4+ has been prepared by a high temperature solid state method. Upon 348 nm excitation, Ca 2 ScTaO 6 :Mn 4+ phosphor showed a high-purity far-red emission at approximately 692 nm and Ca 2 ScTaO 6 : 0.4%Mn 4+ with strongest luminescence performance was used as the optimum doping concentration. The concentration quenching process of Mn 4+ in the Ca 2 ScTaO 6 host is mainly due to quadrupole-quadrupole interactions. In addition, the activation energy (0.3686 eV) for the Ca 2 ScTaO 6 :Mn 4+ phosphor can be obtained according to the temperature-dependence luminescence spectra. Finally, Ca 2 ScTaO 6 : 0.4%Mn 4+ phosphor and a 365 nm light emitting diode (LED) chip are used to fabricate the LED device. The excellent luminescent properties of Ca 2 ScTaO 6 :Mn 4+ suggest that this material could be a promising far-red phosphor for plants growing lighting.
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高影响因子
Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 37
·12658-12666
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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.
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2019
·Vol. 30
·期 12
·11419-11428
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IF 2.195
Zhao Caiyue,Xu Yudong,Wang Lei,Chen Xinyi,Hu Wenjie,Dai Zhaoxiang,Hu Mengyuan,Liu Kai,Shi Min
In this study, Bi 3+ and Mn 4+ co-doped CaAl 12 O 19 phosphors were prepared via high-temperature solid-state reaction method, and their crystal structure, particle morphologies, luminescence properties, charge compensation mechanism and crystal field effect were investigated in detail. A most remarkable tuning effect can be achieved when the Bi 3+ concentration is 5% in CaAl 12 O 19 :Bi 3+ , 0.05% Mn 4+ and the electric multipolar interaction is inferred to be the main mechanism for concentration quenching effect. It is also found that, as charge compensators rather than sensitizers, Bi 3+ ions can effectively tailor the emissions in a wide range through partial reducing Mn 4+ to Mn 2+ . The charge compensation physics presumably involves the shift of Fermi energy level ( E F ) and variations of valence states of manganese ions after Bi 3+ introduction. Moreover, the authors calculated the splitting energy (Δ) and Racah parameters ( B and C ) for Mn 4+ in octahedral sites and Mn 2+ in tetrahedral sites by combining excitation spectra with Tanabe-Sugano diagram. The experimental results will be of certain helpfulness in developing phosphors used in white LED.
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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.
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高影响因子
MATERIALS RESEARCH BULLETIN
·
2016
·
IF 2.435
Miaomiao Du,Fei Tang,Jiaqi Long,Chaoyang Ma,Xuanyi Yuan,Jiantao Zhang,Zicheng Wen,Ran Ma,Yongge Cao
High efficient red phosphor K 2 TiF 6 :Mn 4+ was successfully prepared though a modified two-step co-precipitation method under room temperature. Pure phase of the K 2 TiF 6 powder, with various doping concentration of Mn 4+ range from 4 at.% to 9 at.%, was determined by the X-ray diffraction (XRD) analysis. The Mn 4+ ions were clearly detected by the X-ray photoelectron spectroscopy (XPS) measurement and the electron paramagnetic resonance (EPR). The average particle size, i.e. D50, is around ⿼30 μm scanned by laser particle size analyzer. The highest emission peak centered at about 633 nm was observed from the photoluminescence spectra. The 6 at.% concentration of Mn 4+ shows the best internal emission efficiency of around 99%, which also gives the excellent thermal quench performance. We demonstrated that the maximum color rendering index (CRI) was 85.1 with luminous efficiency as high as 143.82 lm/W, indicating that K 2 TiF 6 :Mn 4+ phosphors had a promising potential for white light-emitting diodes (WLEDs).
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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.
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高影响因子
ACS Applied Nano Materials
·
2025
·
IF 5.5
Yun Tang,Miao Wang,Yalou Xin,Xiaohu Ren,Hudie Yuan,Nan Yan
Perovskite quantum dots (PQDs) and K2SiF6:Mn4+ (KSF) phosphor, renowned for high color purity, are prime candidates for emitters in white light-emitting diodes (WLEDs) for wide color gamut displays. To enhance the luminous efficacy (LE) and working stability of PQDs and KSF-integrated WLEDs, intricate fabrication processes, involving multiple post-treatments of PQDs and their blending with KSF, are often necessitated, inevitably compromising the production efficiency of the device. Herein, we develop a facile in situ synthesis approach that not only effectively passivates surface defects in PQDs and enhances their stability but also simplifies the fabrication process of PQDs and KSF-integrated WLEDs. Specifically, the silica-coated PQDs/KSF (PQDs/KSF@SiO2) composite is synthesized via the in situ growth of MAPbBr3 on an ethanol-treated KSF surface followed by SiO2 encapsulation. The Pb–F coordination and SiO2 encapsulation enable high luminescence intensity and simultaneously enhanced photothermal stability of PQDs. Eventually, the WLED based on PQDs/KSF@SiO2 achieves a high LE of 83.11 lm·W–1 alongside a wide color gamut of 122.6% NTSC standard. Remarkably, the device exhibits excellent working stability, preserving its high LE virtually unaltered after 4 h of continuous operation. This work provides a facile approach to yield WLEDs with superior LE, wide color gamut, and exceptional working stability, positioning them ideally for practical display applications.
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高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Lulu He,Mingxin Zhang,Xiaoliang Dong,Liying Zhang,Ce Shi,Haipeng Ji
Macroscopic Mn 4+ -activated fluoride crystals can exhibit improved resistance to hydrolysis and higher quantum efficiency compared to their micro-sized powder counterparts. Among various Mn 4+ -doped fluorides, Na 2 SiF 6 :Mn 4+ is exceptional for its dominant photoluminescence at 627 nm, a notably short wavelength for this class of materials. While traditionally available only as micro-sized powder, this paper presents, for the first time, the growth of Na 2 SiF 6 :Mn 4+ in the form of millimeter-sized crystals. Utilizing a cooling-induced crystallization technique, we have obtained Na 2 SiF 6 :Mn 4+ crystals that exhibit columnar morphology with single-crystal-like characteristics and pronounced zero phonon line emission at 617 nm. The synthesis was meticulously optimized regarding the cooling protocol, cooling rate, and Mn 4+ doping concentration. With increasing dosage of K 2 MnF 6 in the precursor, a phase transformation from Na 2 SiF 6 :Mn 4+ to (Na,K) 2 SiF 6 :Mn 4+ and K 2 SiF 6 :Mn 4+ was observed for the product crystals. The incorporation of Mn 4+ was hindered during the cooling-induced crystallization of the crystals as the nominal Si/Mn concentration ratios significantly exceed the measured values. Comparison of the deterioration behavior in water suggests that the as-grown Na 2 SiF 6 :Mn 4+ crystals displayed significantly improved stability against water attack compared to the Na 2 SiF 6 :Mn 4+ powder phosphor. This work may inspire the development of more durable phosphor crystals for long-lasting white light LED technologies.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Mufan Wang,Shiying Fan,Shaomin Liu,Xinyong Li
5-Hydroxymethylfurfural (HMF) serves as a key platform molecule for producing high-value chemicals via green and efficient photocatalytic oxidation. Transition metal oxides, particularly spinel substances, are promising heterogeneous catalysts due to their ability to promote interfacial electron transfer. However, the impact of interfacial electron transfer in HMF photocatalytic oxidation on spinel catalysts remains largely unexplored. In this study, we engineered Mn 4+ -O V -Co 2+ active sites in cobalt-based spinel by in-situ (MCO 4-δ -1) and post-doping (MCO 4-δ -2) strategies to investigate their impact on photocatalytic HMF oxidation. The microstructure morphology, chemical valence states, and band structure of prepared catalysts were systematically characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectra (DRS) techniques. The results revealed that the post-doping catalyst (MCO 4-δ -2) exhibited a higher density of surface oxygen vacancy (Ov), significantly enhancing charge transfer and HMF photocatalytic conversion activity. Specifically, MCO 4-δ -2 achieved an outstanding HMF oxidation product yield of 356.55 μmol g −1 under visible light over 4 h. Furthermore, density functional theory (DFT) calculations provided mechanistic insights, revealing that the oxygen in the aldehyde group of HMF preferentially occupies surface Ov sites at Mn 4+ -Ov-Co 2+ interfaces, thereby facilitating selective HMF oxidation pathways. This study not only expand the application scope of cobalt-based spinel photocatalysts in biomass valorization but also provides an insight on the effects of doping-induced interfacial electronic effects in photocatalytic oxidation reactions.
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高影响因子
Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 12
·3016-3025
·
IF 5.976
Chunyan Jiang,Mikhail G. Brik,Lihua Li,Liyi Li,Jie Peng,Jianan Wu,Maxim S. Molokeev,Ka-Leung Wong,Mingying Peng
Recently, as a key red component in the development of warm white light-emitting diodes (WLEDs), Mn4+-doped fluorides with narrow red emission have sparked rapidly growing interest because they improve color rendition and enhance the visual energy efficiency. Herein, a red nanophosphor, K2NaGaF6:Mn4+, with a diameter of 150–250 nm has been synthesized using a simple co-precipitation method. Rietveld refinement reveals that it crystallizes in the space group Fmm with the cell parameter a = 8.25320(4) Å. The exchange charge model (ECM) has been used to calculate the energy levels of Mn4+ ions in K2NaGaF6, which match well with the experimental spectra. The as-synthesized phosphor exhibits a narrow red emission at around 630 nm (spin-forbidden 2Eg → 4A2 transition of Mn4+ ions) when excited at 365 nm (4A2g → 4T1g) and 467 nm (4A2g → 4T2g), with a quantum efficiency (QE) of 61% and good resistance to thermal quenching. Based on the structure, the formation mechanism of ZPL has been discussed. In addition, the concentration-dependent decay curves of Mn4+ in K2NaGaF6 were fitted using the Inokuti–Hirayama model, suggesting that the dipole–dipole interactions determine the concentration quenching. Finally, encouraged by the good performance, a warm LED with a CRI of 89.4 and CCT of 3779 K was fabricated by employing the title nanophosphor as the red component. Our findings suggest that K2NaGaF6:Mn4+ can be a viable candidate for the red phosphor used in warm WLEDs.
研究领域:
材料科学
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光电子学
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固态照明
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发光材料
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荧光粉
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无机化学
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高影响因子
危险品化学品经营许可证（带存储）