Journal of Materials Chemistry C
·
2017
·Vol. 5
·期 47
·12422-12429
·
IF 5.256
T. T. Deng,E. H. Song,Y. Y. Zhou,L. Y. Wang,Q. Y. Zhang
Three isotypic double perovskites A2BAlF6:Mn4+ (A = Rb, Cs; B = K, Rb) were synthesized via a facile co-precipitation method at room temperature. XRD Rietveld refinements and Raman spectra indicate that the neighboring smaller A-site or larger B-site cation in A2BAlF6:Mn4+ lowers structural stability, but suppresses the [AlF6] octahedron to increase the crystal field strength and bond strength of the Al–F bond. Cs2KAlF6:Mn4+ presents a sharp line red light and excellent moisture resistance, but experiences severe thermal quenching. In comparison, altering the A- or B-site cation to Rb, Rb2KAlF6:Mn4+ and Cs2RbAlF6:Mn4+ shows blue shifts in emission and declining water resistance, but enhancements in thermal stability. A combination of static and dynamic emission degradations demonstrates that the water resistance of Mn4+ emission mainly relies on the structural stability of the host matrix; meanwhile, the thermal stability highly depends on the rigidity of its local accommodation. The variations of the temperature-dependent white light-emitting diode (WLED) performances further evidence their sufficient thermal stability for LED applications. These findings suggest that neighboring-cation modulation might be a feasible guideline for exploiting stable Mn4+-activated fluoride red phosphors in warm WLED applications.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 23
·27513-27523
·
IF 2.478
He Youyi,Liu Jun,Gao Yalei,Yan Lijuan,Lv Fengzhen,Liu Fuchi,Long Lizhen
Mn 4+ -activated phosphors have become a hotspot in the development of inorganic red phosphors due to the fascinating photoluminescent properties. Herein, the synergetic manipulation of the flux effect and charge compensation was employed to improve the performance of Mn 4+ -activated CaAl 12 O 19 red phosphors. The crystallinity was improved by appropriate Zn 2+ -doping, while nonradiative transition between Mn 4+ ions is reduced by charge compensation of the formation of Mn 4+ –Mg 2+ pairs with Mg 2+ dopants. Thus, the emission of Mn 4+ -activated CaAl 12 O 19 red phosphors has been remarkably enhanced. The low probability of nonradiative transition between Mn 4+ ions was demonstrated by the thermal stability analysis. To depict the luminescent process, the crystal-field strength ( D q ), and Racah parameters ( B and C ) were calculated to determine the sequence of the energy levels. Meanwhile, the warm WLEDs with high CRI and low CCT were obtained using the prepared phosphors as red-emitting composition. Our results clearly suggested that the synergetic strategy by combining the flux effect and charge compensation is an effective method to enhance the luminescence of CaAl 12 O 19 :Mn 4+ , and CaAl 12 O 19 :Mn 4+ /Zn 2+ /Mg 2+ red-emitting phosphors, which have potential application value in warm WLEDs.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
·
2024
·
IF 3.3
Cimin Su,Donghao Xu,Kuangtong Li,Xiaoqin Xie,Yuhang Ren,Yifei Liu,Yahong Jin,Mingrun Du,Pengfei Shen
In scientific research and industrial applications, an accurate pressure measurement is essential for ensuring process control and safety. However, the pressure measurement range of high-sensitivity pressure measuring materials often fails to meet growing demands. Here, we report a new type of inorganic phosphor, Zn3Ga2GeO8:Mn4+, which offers higher sensitivity and a broader pressure measurement range. By employing in situ high-pressure photoluminescence (PL) measurement techniques, we conducted an in-depth analysis of the spectral characteristics of Zn3Ga2GeO8:Mn4+ under various pressures. The experimental results reveal a notable and consistent linear redshift of the luminescence peak center under pressure loading, exhibiting a pressure sensitivity of up to 0.844 nm/GPa, outperforming numerous current pressure sensing materials. Moreover, absorption spectral analysis indicates that the band gap decreases with increasing pressure, aligning with the phenomenon of redshift observed in PL. Meanwhile, Raman spectroscopy analysis confirms the stability of the material under high-pressure conditions. Our findings support the potential of Zn3Ga2GeO8:Mn4+ as a superior pressure sensor and contribute to the advancement of pressure sensing technology.
研究领域:
材料科学
·
光学工程
·
物理学
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2025
·
IF 3.6
Enjie He,Xiangxiao Chen,Yaqi Wu,Yinkang Cui,Tao Wang,Fangfang Li,Qingyan Han,Xuzhong Zuo,Nian Liu
This study presents the synthesis and characterization of efficient deep-red-emitting CaMg 2 La 2 W 2 O 12 :Mn 4+ , Nd 3+ (CMLW:Mn 4+ , Nd 3+ ) phosphors for application in light-emitting diodes (LEDs) designed for indoor plant cultivation. The phosphors were prepared via a high-temperature solid-state reaction and exhibited an orthorhombic structure with optimal luminescence properties at Mn 4+ (0.90 %) and Nd 3+ (0.60 %) doping concentrations. The enhanced performance of CMLW:0.90 %Mn 4+ , 0.60 %Nd 3+ over its Nd 3+ -free counterpart originates from three synergistic mechanisms: (1) Nd 3+ substitution for larger La 3+ induces lattice shrinkage, shortening the Mn 4+ -O 2- bond length and enhancing the crystal-field strength, thereby increasing the radiative transition probability of 2 E g → 4 A 2g emission at 708 nm; (2) Nd 3+ co-doping suppresses concentration quenching by increasing the critical distance between Mn 4+ ions, as evidenced by prolonged lifetime and higher optimal Mn 4+ concentration; (3) The optimal Nd 3+ concentration improves lattice rigidity while avoiding defect formation observed at higher doping levels. The resulting phosphor demonstrates intense deep-red emission matching the phytochrome P FR absorption band, excellent thermal stability (73.66 % intensity at 453 K), and a high internal quantum efficiency (IQE) of 86.80 %. A prototype LED device exhibits stable deep-red emission and a luminous efficacy of 0.10 lm/W under 365 nm excitation. These results position CMLW:Mn 4+ , Nd 3+ phosphor as a promising candidate for indoor plant cultivation LEDs.
研究领域:
材料科学
·
光学工程
·
农业光电子学
·
固体化学
·
光生物学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL PHYSICS
·
2023
·Vol. 158
·期 23
·
IF 4.4
Yu Yi,Shao Kai,Niu Chonghui,Dan Mingjie,Wang Zhibin,Wang Yingying,Chen Jie,Luo Jiani,Liu Shiying,Xie Zhi
Mn-based phosphors with the wavelength of 700–750 nm are an important category of far-red phosphors that have promising potential in the application of plant lighting, and the higher ability of the far-red light emitting of the phosphors is beneficial to plant growth. Herein, a series of Mn 4+ - and Mn 4+ /Ca 2+ -doped double perovskite SrGd 2 Al 2 O 7 red-emitting phosphors with wavelengths centered at about 709 nm were successfully synthesized by means of a traditional high-temperature solid-state method. First-principles calculations were conducted to explore the intrinsic electronic structure of SrGd 2 Al 2 O 7 for a better understanding of the luminescence behavior in this material. Extensive analysis demonstrates that the introduction of Ca 2+ ions into the SrGd 2 Al 2 O 7 :Mn 4+ phosphor has significantly boosted the emission intensity, internal quantum efficiency, and thermal stability by 170%, 173.4%, and 113.7%, respectively, which are superior to those of most other Mn 4+ -based far-red phosphors. The mechanism of the concentration quench effect and the positive effect of co-doping Ca 2+ ions in the phosphor were extensively explored. All studies suggest that the SrGd 2 Al 2 O 7 :0.1%Mn 4+ , 11%Ca 2+ phosphor is a novel phosphor that can be used to effectively promote the growth of plants and regulate the flowering cycle. Therefore, promising applications can be anticipated from this new phosphor.
研究领域:
材料科学
·
植物学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 20
·6077-6084
·
IF 6.641
Chunyan Jiang,Lihua Li,Mikhail G. Brik,Litian Lin,Mingying Peng
The poor moisture-resistant property of the commercial narrow band red-emitting K2SiF6:Mn4+ phosphor restricts its practical application in high performance warm WLEDs. Herein, we report epitaxial growth via simple ethanol-induced deposition to enhance the luminescence and moisture resistance of K2SiF6:Mn4+. Specifically, an appropriate amount of ethanol at the end of the synthesis leads to epitaxial growth of a K2SiF6:Mn4+ shell. The resultant K2SiF6:Mn4+@K2SiF6:Mn4+ presents higher photoluminescence intensity due to a high Mn4+ critical concentration in the K2SiF6:Mn4+ epitaxial shell. Furthermore, the epitaxial growth of the K2SiF6 shell on K2SiF6:Mn4+ is designed to conquer the moisture resistance. As expected, the formed K2SiF6:Mn4+@K2SiF6 retains 82% of the initial emission intensity after being immersed in water for 4 h and 90% after being exposed to high temperature and humidity (85 °C, 85%) for 10 days. By employing K2SiF6:Mn4+@K2SiF6 as a red phosphor, a packaged white LED exhibits excellent performance with a CRI of 96.5, a CCT of 2879 K and a luminous efficacy of 119.74 lm W−1. More importantly, this fabricated WLED device retains high luminous efficacy and undergoes minor chromatic coordinate changes when aged at high temperature and humidity (85 °C, 85%). Therefore, these findings not only illustrate the effect of ethanol addition on the photoluminescence intensity of Mn4+ doped phosphors in the synthesis process, but also provide a facile strategy to improve the moisture resistance of K2SiF6:Mn4+ for warm WLEDs in the future.
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
·
2021
·
IF 4.527
Sijin Zhang,Shujie Gai,Xiaojuan Zhang,Mao Xia,Zhi Zhou,Xiao Cheng,Maohai Yao,Maxim S. Molokeev,Qiuju Feng
Red and far-red emitting phosphors have been widely used in phosphor-converted light emitting diode (pc-LED) devices to provide lighting for indoor plant growth, thus achieving desired product qualities. Among the many ways to optimize phosphors’ optical performance, cationic substitution is one of the most effective methods. In this study, red phosphors (Li 2 MgTi 1- x - y O 4 : x Mn 4+ , y Ge 4+ ) were synthesized by high temperature solid state method and the optical performance of phosphors were improved with increasing Ge 4+ constituents. In particular, luminescence intensity of Li 2 MgTiO 4 : 0.002Mn 4+ , 0.1Ge 4+ increased by 152% under 468 nm excitation, and the thermostability of emission intensity increases from 22% ( y = 0) to 43% ( y = 0.1), which is about twice as much. Finally, pc-LED device was fabricated via the red phosphor Li 2 MgTiO 4 : 0.002Mn 4+ ,0.1Ge 4+ coated on a 470 nm ultraviolet chip. By changing the proportion of the phosphor, the electroluminescence spectra of pc-LED device could match well with the absorption regions of plant pigments. Therefore, Li 2 MgTiO 4 : 0.002Mn 4+ , 0.1Ge 4+ phosphor has potential application in plant lighting. Furthermore, this work can offer some helpful references for improving luminescent efficiency by simply modulating the chemical composition.
研究领域:
材料科学
·
光学
·
农业工程
✓ 已验证
DOI
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.
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
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.
研究领域:
材料科学
·
光学工程
·
显示技术
✓ 已验证
产品关联
DOI
高影响因子
Advanced Optical Materials
·
2024
·Vol. 12
·期 19
·2400250
·
IF 8
Wenyu Tang,Yuanjing Wang,Yayun Zhou,Chuang Zhang,Zhen Chen,Fanquan He,Enhai Song,Qinyuan Zhang
Mn 4+ -activated red-light fluorides are widely used in high-quality displays, due to the narrow-spectral emission. However, achieving exceptional chromaticity coordinates and appropriate quantum efficiency (QE) at the same time is a great challenge. Herein, a Li substitution strategy is proposed for enhancing QE and improving the thermal stability of red-light Mn 4+ -activated Cs 2 NaGaF 6 (CNGF). The external quantum efficiency (EQE) of optimal Cs 2 NaGaF 6 : Mn 4+ , Li + (CNGF: Mn 4+ , Li + ) is improved from 15.79% to 33.61% and thermal stability increases from 68.4% to 85.5% (intensity at 150 °C relative to room temperature). EQE enhancement mechanism on the strategy is explored that Li substitution increases the local structural distortion of Mn 4+ for relieving the parity forbidden, and promotes Mn 4+ doping in the host lattice, which provides new insights for improving the QE of Mn 4+ non-equivalent doped fluorides. Moreover, with exceptional chromaticity coordinates of (0.7029, 0.2970), optimal sample CNGF: 4.8 mol% Mn 4+ ,0.9 mol% Li + can be used to fabricate white light-emitting diode (w-LED) backlight, which obtains wide color gamut of 110.68% National Television Standards Committee (NTSC) and high luminous efficacy of 110.57 lm W −1 , indicating that CNGF: Mn 4+ , Li + is a promising candidate for the next generation of wide gamut and efficient displays.
研究领域:
材料科学
·
光学工程
·
显示技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2022
·Vol. 105
·期 6
·4230-4241
·
IF 4.186
Zhanglin Chen,Zhaobo Tian,Jie Zhang,Fei Li,Songmo Du,Shijia Zhang,Kaiming Zhu,Wei Cui,Xuanyi Yuan,Kexin Chen,Guanghua Liu
A novel deep-red-emitting phosphor Ca 2 ScNbO 6 :Mn 4+ is prepared via a high-temperature solid-state reaction and its luminescent properties are systematically investigated. The results show that Mn 4+ -activated Ca 2 ScNbO 6 phosphors have broad absorption in ultraviolet region, and show bright deep-red emission at 692 nm. The optimal doping concentration, crystal-field strength, internal quantum efficiency, and mechanism of concentration and thermal quenching effects are discussed in detail. Moreover, NaF flux is screened out to improve both luminescent intensity and morphology of the phosphor. Finally, a red light-emitting diode (LED) lamp is fabricated with as-prepared Ca 2 ScNbO 6 :Mn 4+ phosphors and a 365 nm LED chip. The electroluminescence spectra show a good overlapping with phytochrome P R and P FR absorbance. The results provided the as-synthesized Ca 2 ScNbO 6 :Mn 4+ phosphors a great potential in plant growth lighting.
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
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.
研究领域:
材料科学
·
催化化学
·
能源化学
✓ 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）