CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Yao Yang,Yanli Shi,Junjing Duan,Kailei Lu,Gang Cheng,Yiding Zhao,Zhangyi Huang,Peitong Li,Nian Wei,Xinghua Zhu,Jianqi Qi,Tiecheng Lu
The exploration of new red phosphors is important for the development of white light-emitting diodes (w-LEDs), as existing red phosphors exhibit low efficiency and low performance. This work aims to enhance the photoluminescence characteristics of a red-emitting Gd 2 Zr 2 O 7 :Eu 3+ phosphor by co-doping with Al 3+ . Eu 3+ single-doped and Eu 3+ and Al 3+ co-doped Gd 2 Zr 2 O 7 nanophosphors that could be efficiently pumped by commercial near-UV LED chips were prepared by a modified liquid–solid–solution phase-transfer method. X-ray diffraction data revealed that the synthesized phosphors were well crystallized with single-phase fluorite structure. Scanning electron microscopy images showed that the particle size ranges from 15 to 25 nm. In addition, the optical performance of the samples was characterized by fluorescence spectroscopy and lifetime spectroscopy. The effect of Al 3+ on the luminescence performance of the Eu 3+ -doped Gd 2 Zr 2 O 7 phosphor was studied in detail. The emission intensity of the Gd 1.93 Zr 1 · 97 O 7 :Eu 3+ 0.07 Al 3+ 0.03 phosphor was found to be 620% stronger than that of the single-doped Eu 3+ phosphor. These results unambiguously show that the Gd 1.93 Zr 2- x O 7 :Eu 3+ 0.07 Al 3+ x phosphors are promising candidates for application in w-LEDs.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
ACS Applied Electronic Materials
·
2019
·
IF 0
Wei Yan,Shuoting Chen,Yixin Liu,Zhiyu Gao,Yi Wei,Guogang Li
High-performance and thermally stable phosphors play an important role in high-quality white light-emitting diode (pc-WLED) lighting. In this work, we proposed a cation substitution strategy to improve the luminescence performance of blue-emitting Bi3+-doped Ca4ZrGe3O12 (abbreviated as CZGO) phosphor. As expected, the introduction of Sr2+ and Si4+ can improve photoluminescence intensity and thermal stability. The photoluminescence intensity can be increased by 6.7 times. The internal quantum efficiency (IQE) can achieve 88.1%. Based on Rietveld refinement results, the corresponding enhancement mechanism is ascribed to the local lattice modification and the improved structure rigidity. In addition, controllable color tuning from blue to red light is successfully realized through designing Bi3+ → Eu3+ energy transfer. The energy transfer efficiency (ηT) is 0.55 in CZGO:2% Bi3+, 15% Eu3+ phosphor. The energy transfer mechanism is discussed in detail. The prototype pc-WLEDs with blue/red dual-emitting CZGO:2% Bi3+, 10% Eu3+ possess a high color rendering index (CRI = 90.8) and low correlated color temperature (CCT = 4372 K). The above investigations indicate that CZGO:Bi3+ and CZGO:Bi3+, Eu3+ are promising blue-to-red tunable phosphor candidates for pc-WLED applications.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Yuanjing Wang,Yayun Zhou,Hong Ming,Yifei Zhao,Enhai Song,Qinyuan Zhang
Mn4+ non-equivalent doped fluorides with high color purity red emission and relatively short decay time are crucial for wide color gamut displays and emerging applications, whereas the low quantum efficiency (QE) restrains their further applications. Herein, the luminescence of Mn4+ non-equivalent doped fluoride K2NaAlF6:Mn4+ (KNAF:Mn4+) is significantly enhanced via a heterovalent co-doping strategy, where the luminescence intensity is obviously increased by ∼85%, but the decay time is almost unchanged. The experimental characterization and density functional theory (DFT) calculations provide an understanding of the luminescence enhancement mechanism of heterovalent co-doping, which is enabled by simultaneously improving the stability of Mn4+ and reducing the number of quenching centers (defects and impurities). Combining the short-decay-time (τ = 4.03 ms) emission KNAF:Mn4+, Mg2+ and long-decay-time (τ = 9.23 ms) emission K2SiF6:Mn4+, a novel monochromatic multiplexing mode in the millisecond order is presented, which can be decoded not only in high-efficiency by a digital camera but also with a high security. This work provides a new optical multiplexing for the information security applications and also inspires the design of high-efficiency Mn4+-activated luminescent materials.
研究领域:
材料科学
·
光学
·
信息科学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·Vol. 106
·期 8
·4818-4830
·
IF 3.9
Qianwen Cao,Liang Li,Jing Xie,Yuan Feng,Wenming Wang,Yan Pan,Xiantao Wei,Yong Li
Phosphors doped with Mn 4+ ions have strong emission in the red and far-red light regions and are therefore used as red phosphors for indoor plant cultivation light-emitting diodes (LEDs) and white LEDs (w-LEDs). This paper introduces La 2 Mg(Mg 1/3 Ta 2/3 )O 6 : Mn 4+ (Mg 2 La 3 TaO 9 : Mn 4+ ) red phosphors prepared by conventional high-temperature solid-phase method. The broad excitation band of Mg 2 La 3 TaO 9 : Mn 4+ phosphor is effectively excited by ultraviolet and blue light in the range of 250–600 nm, with the emission of 707 nm centered on far-red light. The phosphor has a high color purity of 99.07% and an internal quantum efficiency of 59.87%. To further enhance the performance of the phosphor, a cation substitution method was adopted in this paper to synthesize La 2 Mg(Al 1/2 Ta 1/2 )O 6 : Mn 4+ phosphor by replacing [1/3Mg 2+ –2/3Ta 5+ ] in La 2 Mg(Mg 1/3 Ta 2/3 )O 6 : Mn 4+ with [1/2Al 3+ –1/2Ta 5+ ]. The luminescence intensity and thermal stability of the samples were enhanced. The emission spectrum of the Mg 2 La 3 TaO 9 : Mn 4+ samples matched well with the phytochrome P FR (phytochrome that absorbs far-red light) and is suitable for the preparation of LEDs for indoor plant cultivation. The concentration quenching effect of the samples was investigated, the main mechanism of which is the electric dipole–dipole interaction. Red LEDs and w-LEDs devices were prepared with the synthesized phosphors that produce light stably at different currents. The w-LEDs have a correlated color temperature of 5310 K and a color rendering index of 80.1. Therefore, these samples are expected to be used as red components for w-LEDs.
研究领域:
材料科学
·
光学工程
·
植物栽培技术
✓ 已验证
DOI
高影响因子
Advanced Optical Materials
·
2017
·Vol. 5
·期 20
·1700448
·
IF 6.875
Kai Zhang,Chong-Geng Ma,Jun-Ying Zhang,Bo-Mei Liu,Yang Zhou,Shao-Qiang Guo,Jia-Yue Xu,Jing-Shan Hou,Yong-Zheng Fang,Li-Rong Zheng,Hong-Tao Sun
Relaxing chemical pressure in phosphors with large-size-mismatched dopants, aiming at attaining high-efficiency luminescence and a higher dopant concentration, remains a challenging subject of continuous research effort. Originally seen as undesirable and detrimental to the performance of luminescent systems, this study demonstrates that the formation of a tiny amount of oxygen vacancies favors chemical pressure relaxation (CPR), resulting in topotactic transformation of poorly luminescent parent phases to highly luminescent cousins, as exemplified by a model system of Bi 3+ -doped Lu 2 O 3 . The integration of experimental observations with theoretical calculations reveals that the emergence of oxygen vacancies adjacent to Bi 3+ can expand its size of coordination geometry, thus releasing the chemical pressure and significantly influencing the emission characteristics. Importantly, it is illustrated that the concept of oxygen-vacancy-mediated CPR is sufficiently general to allow the optimization of luminescence from other classes of foreign-ion-doped phosphors plagued by size mismatch. It is suggested that this concept can be applied to an array of optical materials in various forms, and also provides unique opportunities for tuning other properties of functional materials that are sensitive to local coordination environments of dopants.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 9
·1453
·
IF 5.719
Chen Wang,Luyao Feng,Junxiao Liu,Jing Fu,Jinglin Shen,Wei Qi
Au nanocluster (AuNCs)-based luminescent functional materials have attracted the interest of researchers owing to their small size, tractable surface modification, phosphorescence lifetime and biocompatibility. However, the poor luminescence quantum yield (QY) of AuNCs limits their practical applications. Herein, we synthesized a type of AuNCs modified by 4,6-diamino-2-mercaptopyrimidine hydrate (DPT-AuNCs). Furthermore, organic acids, i.e., citric acid (CA) and tartaric acid (TA), were chosen for co-assembly with DPT-AuNCs to produce AuNCs-based luminescent materials with enhanced emission. Firstly, it was found that CA could significantly enhance the emission of DPT−AuNCs with the formation of red emission nanofibers (QY = 17.31%), which showed a potential for usage in I−detection. Then···π/π···π interaction between the CA and the DPT ligand was proposed as crucial for the emission. Moreover, chiral TA could not only improve the emission of DPT-AuNCs, but could also transfer its chirality to DPT-AuNCs and induce the formation of circularly polarized luminescence (CPL)-active nanofibers. It was demonstrated that the CPL signal could increase 4.6-fold in a ternary CA/TA/DPT-AuNCs co-assembly system. This work provides a convenient way to build AuNCs-based luminescent materials as probes, and opens a new avenue for building CPL-active materials by achiral NCs through a co-assembly strategy.
研究领域:
材料科学
·
光学
·
生物医学工程
✓ 已验证
DOI
高影响因子
Methods and Applications in Fluorescence
·
2022
·Vol. 10
·期 3
·035004
·
IF 3.849
Linli Xiong,Yong Zheng,Haibo Wang,Jiangyang Yan,Xuguang Huang,Hongyun Meng,Chunhua Tan
A novel fluorescence sensor for successive detection of Cu2+ and Fe3+ based on anti-B18H22 derivative which possesses 5-hydroxyisoquinoline as an ionophore was synthesized via a one-pot and its structure and photophysical properties were characterized by NMR, HRMS, FTIR, UV–vis, PL and theoretical calculation. The fluorophore displays two emission peaks at 460 nm and 670 nm in THF solution coming from the emission of the locally excited state and intramolecular charge transfer fluorescence, respectively. The complex exhibited obvious aggregation-induced emission enhancement (AIEE) characteristics in THF/H2O solution by increasing the aqueous concentration from 70% to 95%. The AIEE molecules showed a high selectivity towards Cu2+ over other metal ions by forming a 2:1 metal-to-ligand complex in THF/H2O (fw = 20%) solution, the fluorescence intensity increased as a linear function of the Cu2+ concentration at 460 nm due to the inhibition of PET effect. The fluorescent emission was quenched linearly by the addition of Fe3+, which provides a method for successive determination of Cu2+ and Fe3+ based on 'off-on-off' fluorescence of the fluorescent. The detection limit of Cu2+ and Fe3+ was 5.7 × 10−6 M and 7.2 × 10−5 M respectively. Morever, a rapid identification of Cu2+ in the aqueous solution by naked eyes can be realized. In addition, the molecules were pH-sensitive, the fluorescence quenching can be observed in strongly alkaline environment. The method has been applied to the determination of copper ions in water samples with satisfactory results.
研究领域:
化学
·
材料科学
✓ 已验证
DOI
高影响因子
ANALYST
·
2021
·Vol. 147
·期 3
·417-422
·
IF 4.616
Long Chuan Zhang,Yu Meng Yang,Ling Liang,Yong Jian Jiang,Chun Mei Li,Yuan Fang Li,Lei Zhan,Hong Yan Zou,Cheng Zhi Huang
Carbon dots have promising prospects for analytical and monitoring purposes, but are greatly hindered by the aggregation-induced luminescence quenching owing to the π–π interaction or the non-radiation-excited radical complex formation. Herein hydrothermally prepared orange-yellow fluorescent carbon dots (O-CDs) show an aggregation-induced fluorescence enhancement (AIFE) with Cu2+ owing to the complexation of Cu(II) and the O-CDs. Cu2+ was then sensitively and selectively detected in the linear range from 0.02 to 30 μM with the detection limit of 14 nM, making the detection of Cu2+ in fresh water and E. coli lysate successful, showing that the as-prepared O-CDs could be well applied to the environmental monitoring of heavy metals.
研究领域:
分析化学
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 5
·777
·
IF 5.719
Pei Zhou,Nirmal Goswami,Tiankai Chen,Xiaoman Liu,Xin Huang
The research of aggregation-induced emission (AIE) has been growing rapidly for the design of highly luminescent materials, as exemplified by the library of AIE-active materials (or AIEgens) fabricated and explored for diverse applications in different fields. Herein, we reported a relay luminescence enhancement of luminescent Au nanoclusters (Au NCs) through AIE. In addition, we demonstrated the emergence of reduced aggregation-caused luminescence by adjusting the temperature of the Au NC solution. The key to induce this effect is to attach a thermosensitive polymer poly(N-isopropylacrylamide) (PNIPAAm) on the surface of Au NCs, which will shrink at high temperature. More interestingly, the as-synthesized Au NCs-PNIPAAm can self-assemble into vesicles, resulting in an obvious decrease in the luminescence intensity in aqueous solution. The combination of relay luminescence enhancement (by AIE) and luminescence decrease (induced by thermosensitive polymers) will be beneficial to the understanding and manipulation of the optical properties of Au NCs, paving the way for their practical applications.
研究领域:
材料科学
·
光学
·
纳米技术
✓ 已验证
DOI
高影响因子
ACS Applied Optical Materials
·
2024
·
IF 0
Jiaxin Li,Yujiao Zhang,Pengli Wang,Dan Xiao,Cuisong Zhou
Alloyed upconversion nanoparticles (aUCNPs, NaYbF4:10% Er@NaYF4) with high Yb3+ doping were designed to brighten luminescence, exploring multicolor patterns of information encryption. The luminescence intensity of aUCNPs was 2.3 times higher than that of common doped UCNPs reported (dUCNPs, NaYF4:20% Yb, 2% Er@NaYF4). Furthermore, because of the high Yb3+ doping (90%), both green and red emissions of aUCNPs were enhanced, ∼4.2 and ∼17.2 times stronger than that of NaYF4:20% Yb, 10% Er@NaYF4, respectively. The reasons for the aUCNPs having a brightened luminescence were explored by synthesizing four UCNPs with different structures and comparing their luminescence. These are attributed to their unique features: (1) a larger absorption cross section for accumulating energy, (2) more efficient energy transfer between Yb3+ and Er3+, and (3) their inert shell inhibiting surface quenching. Eventually, three colors including yellow, orange, and red were obtained by combining aUCNPs and neutral red (NR) taking advantage of the inner filter effect (IFE), and aUCNPs were thus successfully applied in information encryption with multicolor patterns.
研究领域:
材料科学
·
光学
·
信息安全
✓ 已验证
DOI
JOURNAL OF APPLIED POLYMER SCIENCE
·
2016
·Vol. 134
·期 10
·
IF 1.866
Fei Fang,Fan Kong,Xueqin Zhang,Mengqi Lin,Yichi Zhang,Shounian Ding
A series of amphiphilic poly(N-vinyl carbazole) (PVK) block copolymers containing tris(8-hydroxyquinoline) aluminum (Alq 3 ) have been synthesized via reversible addition-fragmentation chain transfer (RAFT) radical polymerization with trithiocarbonate terminated polyethylene glycol (PEG) as a RAFT agent. The chemical structures of the block copolymers have been identified by 1 H nuclear magnetic resonance and Fourier transform infrared spectrometer. The analysis of gel permeation chromatography indicates that the polydispersity indices of the block copolymers are lower than 1.30. The results of thermogravimetric analysis show that the decomposition temperatures of the copolymers are higher than 330 ° C . The optical properties of the copolymers have been investigated and the obviously enhanced emission from Alq 3 has been found due to resonance energy transfer from PVK to Alq 3 . © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44573.
研究领域:
高分子化学
·
材料科学
·
光电子学
·
纳米功能材料
·
聚合物合成
·
荧光材料
·
能量转移
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
·
2020
·
IF 4.189
Pengfei Shen,Douglas A. Blom,Sen Shao,Jinhyuk Choi,Thomas Vogt,Yanming Ma,Lin Wang,Yongjae Lee
Tuning of physical properties opens up opportunities for new applications of known materials, as the changes induced by hydrostatic pressures can sometimes be mimicked by chemical pressures created by appropriate substitutions or at the interfaces. In contrast to bulk In2O3, where photoluminescence (PL) is reduced by pressure, pressure-induced photoluminescence enhancement (PIPE) by a factor of 4.4 was found in In2O3 nanowires (NWs). Density functional theory (DFT) calculations indicate that PIPE in NWs may be ascribed to the orbital overlap between oxygen-induced defect levels and the conduction band minimum (CBM), which does not occur in bulk In2O3. Both the PL intensity and absorption spectra of In2O3 NWs point to a discontinuity near 16 GPa. Rietveld refinements indicate that these changes in optical properties are concomitant with structural distortions, leading to strained bonds in the InO6 octahedra and trigonal prisms. The optical transmittance (T) of the NWs after compression up to 5.29 GPa is reversible after the pressure release. However, NWs compressed to 12.27 GPa and then reinvestigated at ambient pressure reveal that T increases. At compressions of up to 24.85 GPa, T at ambient conditions was enhanced by 8.29%. Synchrotron X-ray scattering and Raman spectra of NWs compressed to 24.85 GPa indicate that a local distortion of the cubic bixbyite structure is present at ambient conditions. This study establishes a correlation between changes in PL and T of In2O3 NWs and local structural distortions resulting in oxygen-induced defects, which overlap with the conduction band states as suggested by DFT calculations. Our work suggests that the optical properties of ternary metallic oxide NWs with bixbyite structure might be improved by appropriate substitutions.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）