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Highly fluorescence Ta_(4)C_(3) MXene quantum dots as fluorescent nanoprobe for heavy ion detection and stress monitoring of fluorescent hydrogels

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Chinese Chemical Letters 2022年第4期33卷 1850-1854页

作者： Shouzhen Li Junfei Ma Xuelin Zhao Peide Zhu Meng Xu Yingchun Niu Dixian Luo Quan Xu State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development National Energy Shale Oil Research and Development CenterChina University of Petroleum(Beijing)Beijing 102249China Department of Musculoskeletal Tumor Senior Department of Orthopedicsthe Fourth Medical Center of PLA General HospitalBeijing 100142China Department of Laboratory Medicine Huazhong University of Science and Technology Union Shenzhen Hospital(Nanshan Hospital)Shenzhen 518000China

Compared with other transition metal Mxene derived quantum dots(MQD_(S)),Ta-based Mxene quantum dots have good functionality,but Ta-based Mxene quantum dots and their applications have not been studied so *** this paper,we report for the first time the synthesis of high fluorescence quantum yield(QY) N-doped Ta_(4)C_(3) quantum dots(N-MQDs) using Ta_(4)C_(3) quantum dots in acid reflux damaged Ta_(4)C_(3) nanosheets as precursors and ethylenediamine as nitrogen *** prepared N-MQDs have excellent blue photoluminescence(PL) properties,particle size is only 2.60 nm,QY is up to 23.4%,and good *** addition,it has been reported that N-MQDs can be used as fluorescent probe for detection of Fe;and remote force sensing analysis In liquid ion sensing,N-MQDS shows a unique selective quenching of Fe;with a detection limit as low as 2 μmol/L,and has great potential as a fast and super-sensitive fluorescent probe for the detection of heavy *** importantly,in solid mechanics sensing,the introduction of N-MQDs into self-healing hydrogels can be developed into a fluorescent hydrogel that can be used for accurate remote force measurement and applied in the field of mechanical sensing ***,Ta-based N-MQDs show excellent potential in the field of fluorescence sensing,which provides a door for multi-dimensional sensing of new materials in the future.

关键词： MXene quantum dots Fluorescent probe Fluorescent hydrogel Hydrothermal method quantum yield

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Emission tunable of Mg_(0.695)Si_(0.695)Al_(1.39)O_(3.65)N_(0.35):Eu^(2+),Mn^(2+) oxynitride phosphors via energy transfer for WLEDs

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Journal of Rare Earths 2021年第6期39卷 643-650,I0002页

作者： Yijun Yu Yi Chen Liang Chen Yuyu Shen Xiao Liu Degang Deng Shiqing Xu College of Optical and Electronic Technology China Jiliang UniversityHangzhou 310018China Institute of Optoelectronic Materials and Devices China Jiliang UniversityHangzhou 310018China

A series of Eu^(2+)doped and Eu^(2+)/Mn^(2+) co-doped Mg_(0.695)Si_(0.695)Al_(1.39)O_(3.65)N_(0.35)(MSAON) phosphors were synthesized by solid-state reaction at a lower temperature of 1500℃.The crystal morphology and structure of MSAON host were characterized by SEM,TEM and *** quantum yield(QY) for Eu^(2+)doped MSAON phosphors was measured as high as 62%,indicating the excellent luminous *** the Eu^(2+)/Mn^(2+)co-doped MSAON phosphor,the photoluminescence spectrum and delay curves reveal the efficient energy transfer(ET) process from Eu^(2+)to Mn^(2+)***,the corresponding energy transfer efficiency,critical distance and mechanism are discussed in ***-dependent emission spectrum shows the thermal and color *** emission color of MSAON:Eu^(2+),Mn^(2+)phosphors could be tuned from blue through white to red via varying the concentration of Mn^(2+) ***-light-emitting diodes(WLEDs) were successfully fabricated by encapsulating the phosphors in nUV LED(365 nm) devices obtaining white light with color rendering index(CRI) as high as *** results reveal that the MSAON:Eu^(2+),Mn^(2+)phosphors could have potential application in the field of n-UV WLEDs.

关键词： Mg_(0.695)Si_(0.695)Al_(1.39)O_(3.65)N_(0.35):Eu^(2+) Mn^(2+) Emission tunable quantum yield Photoluminescence Energy transfer Rare earths

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Improvement of photoemission performance of a gradient-doping transmission-mode GaAs photocathode

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Chinese Physics B 2011年第11期20卷 534-540页

作者：张益军牛军赵静熊雅娟任玲常本康钱芸生 Institute of Electronic Engineering and Optoelectronic Technology Nanjing University of Science and Technology

Two types of transmission-mode GaAs photocathodes grown by molecular beam epitaxy are compared in terms of activation process and spectral response, one has a gradient-doping structure and the other has a uniform-doping structure. The experimental results show that the gradient-doping photocathode can obtain a higher photoemission capability than the uniform-doping one. As a result of the downward graded band-bending structure, the cathode performance parameters, such as the electron average diffusion length and the surface electron escape probability obtained by fitting quantum yield curves, are greater for the gradient-doping photocathode. The electron diffusion length is within a range of from 2.0 to 5.4μm for doping concentration varying from 10^19 to 10^18 cm^-3 and the electron average diffusion length of the gradient-doping photocathode achieves 3.2 μm.

关键词： transmission-mode photocathode gradient-doping Cs-O activation quantum yield

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Preparation, characterization and luminescence behavior of some samarium complexes

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Rare Metals 2021年第9期40卷 2618-2626页

作者： Archana Chauhan Ritu Langyan Department of Chemistry Kurukshetra UniversityKurukshetra 136119India

The synthesis of luminescent complexes of Sm(III) with the general formula [Sm(L)_(3)·(X)] was done in powder form. In the formula, L is 6-methyl-4-oxo-4 H-1-benzopyran-3-carboxaldehyde and X represents 2H_(2)O(C1), 1,10-phenanthroline(C2), 2,20-bipyridine(C3);bathophenanthroline(C4) and neocuproine(C5). The complexes were characterized by using various analytical and spectroscopic tools like elemental analysis, electrospray ionization mass spectrometry(ESI–MS+), Fourier transform infrared spectroscopy(FTIR), ultraviolet–visible(UV–Vis) spectroscopy, thermo-gravimetric analysis/differential thermal gravimetric analysis(TGA/DTG), field emission scanning electron microscopy(FESEM), powder X-ray diffraction(XRD), and photoluminescence(PL)studies. TGA/DTG showed high thermal stability of synthesized complexes. Powder XRD depicts that the average particle size lies in the nano-range. On monitoring at the excitation wavelength of 370 nm, the complexes display characteristic luminescence peaks of Sm(III) at ~564,~600 and ~647 nm assigned to^(4)G_(5/2)→^(6)H_(5/2),^(4)G_(5/2)→^(6)H_(7/2), and ^(4)G_(5/2)→6H9/2 transitions, respectively, with the most intense transition at ~600(orange emission) and~647 nm(bright red emission) in liquid and powder state, respectively. The investigations demonstrate that the synthesized novel complexes might be practically useful in electroluminescent devices, bio-assays, and liquid lasers due to their attractive photoluminescent properties.

关键词： Samarium complexes Luminescence Thermal analysis quantum yield

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Synthesis and luminescent properties of terbium complex containing 4-benzoylbenzoic acid for application in NUV-based LED

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Journal of Rare Earths 2016年第2期34卷 130-136页

作者：孙乃群赵希瑾杨亚敏李利平张爱琴贾虎生刘旭光 Key Laboratory of Interface Science and Engineering in Advanced Materials of Taiyuan University of Technology Ministry of Education College of Materials Science and Engineering Taiyuan University of Technology College of Textile Engineering Taiyuan University of Technology College of Chemistry and Chemical Engineering Taiyuan University of Technology

A novel Tb(III) ternary complex Tb(p-BBA)3MAA was synthesized with 4-benzoylbenzoic acid (p-BBA) and methacrylic acid (MAA) as ligands. The complex was characterized by IR, UV-visible, thermogravimetric analysis and fluorescence spectroscopy. Monitored at 544 nm, the complex displayed wide and strong excitation band at 300–400 nm, which matched well with the 365 nm-emitting UV chip. The complex exhibited excellent green emission at 544 nm (5D4→7F5 transition of Tb3+) under an excitation at 365 nm. Besides, the complex showed high thermal stability. Its intramolecular energy transfer process was further discussed. Fur-thermore, the complex also had higher fluorescence lifetime (1.38 ms) and higher quantum yield (0.372). Finally, electroluminescent properties indicated that when used to fabricate LED with 365 nm UV chip (power efficiency is 18.6 lm/W), the complex remained its favorable optical performance. These results implied that Tb(p-BBA)3MAA could be used as a green phosphor for NUV-based white LED.

关键词： 4-benzoylbenzoic acid Tb(III) complex fluorescence quantum yield lifetime rare earths

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Optical properties of wavelength-tunable green-emitting color conversion glass ceramics

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Chinese Physics B 2017年第12期26卷 596-599页

作者：李杨胡丽丽杨波波石明明邹军 Key Laboratory of Materials for High Power Laser Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China University of Chinese Academy of Sciences Beijing 100049 China School of Materials Science and Engineering Shanghai Institute of Technology Shanghai 201418 China School of Science Shanghai Institute of Technology Shanghai 201418 China

Color conversion glass ceramics are prepared by cosintering borosilicate glass frits and green 0.06Ce：Y2.94（Al1-xGax）5O12 phosphors. The crystal structures, the influence of Ga concentration on the photoluminescence （PL）, and reliability properties of the color conversion glass ceramics are investigated. The PL emission wavelengths of 0.06Ce：Y2.94（Al1-xGax）5O12 glass ceramics show blue shift from 545 nm to 525 nm with increasing Ga content （x value） under excited at 460 nm. Reliability test results show that the quantum yield （QY） of 0.06Ce：Y2.94（Al1-xGax）5O12 glass ceramics decreases from 70.60% to 59.06% with x value increasing from 0.15 to 0.35 under the ambient condition of 85℃/RH85% for the exposure time of 168 h. And the quantum yield （QY） of 0.06Ce：Y2.94（Al1-xGax）5O12 glass ceramics decreases from 65.13% to 52.23% after being soaked into boiled water for 4 h. The finding reveals that the addition of Ga can deteriorate the reliability of the color conversion glass ceramics.

关键词： color conversion glass ceramic photoluminescence wavelength quantum yield reliability property

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Fluorescence of Nanosized Composite of Mesoporous Molecular Sieve and Europium (Ⅲ) Complex

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Journal of Rare Earths 2004年第S1期22卷 1-7页

作者：尹伟 Department of Chemistry Guangdong Education Institute Guangzhou 510310 China

Rare earth complexes Eu(Phen)_2(TTA)(Bipy)(NO_3)_3 and Eu(L)_x(TTA)_(4-x)(NO_3)_3 (L=Phen or Bipy; x=4, 3, 2, 1, 0) solutions (1×10^(-3) mol·L^(-1)) were prepared in EtOH. The luminescent experimental results show that the synergy effect of Phen and TTA exists in Eu^(3+) complexes. But when the ligands of Bipy and TTA coexist in europium complex, the synergy effect does not exist. If a solution of a europium complex has a specific electron configuration of excited state, the solution of the complex has an intensity of fluorescence and a quantum yield. 2.5×10^(-5) mol·L^(-1) Eu(Phen)_2(TTA)_2(NO_3)_3 solution (λ_(ex)=347.0 nm) possesses a maximal quantum yield (0.25) and the strongest fluorescent intensity. The nanosized mesoporous molecular sieves possess spherical cage structure that is fit for preparation of composite materials with encapsulation method. The research results of XRD and IR show that the guest molecule is encapsulated into the channels of the host. The thermostability of the guest molecule in the channels of the host (CH_3)_3Si-MCM-41 is enhanced. The fluorescent intensity and the half-life of nanosized composites of (CH_3)_3Si-MCM-41 and Eu^(3+) complexes are stronger and longer than those of encapsulation products of MCM-41 and Eu^(3+) complexes. Supramolecular encapsulation products emit characteristic radiation of Eu^(3+) ion, vesting in the transitions of (()~5D_0→()~7F_J) (J=0, 1, 2, 3, 4), respectively; each excitation peak of fluorescent spectra of the composites is assigned to an excited electron configuration of Eu^(3+) ion. The host with lipophilic channels is more favourable to fluorescence of the rare earth complex than hydrophilic mesoporous molecular sieve; The fluorescent intensity of (CH_3)_3Si-MCM-41-Eu(Phen)(TTA)_3(NO_3)_3 can match with that of Eu(Phen)(TTA)_3(NO_3)_3 powder sample. These results could be assumed to result from strong radiation absorption of the guest complex molecule (blue shift of maximum excitation wavelength)

关键词： nanosized composite MCM-41 (CH_3)_3Si-MCM-41 supramolecular encapsulation luminescence quantum yield rare earths

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A photolysis coefficient for characterizing the response of aqueous constituents to photolysis

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Frontiers of Environmental Science & Engineering 2016年第3期10卷 428-437页

作者： David R. HOKANSON Ke LI R. Rhodes TRUSSELL Trussell Technologies Inc. Pasadena CA 91101 USA College of Engineering University of Georgia Athens GA 30602 USA

UV photolysis and UV based advanced oxidation processes （AOPs） are gaining more and more attention for drinking water treatment. quantum yield （Ф） and molar absorption coefficient （ε） are the two critical parameters measuring the effectiveness of photolysis of a compound. The product of the two was proposed as a fundamental measure of a constituent＇s amenability to transformation by photolysis. It was shown that this product, named the photolysis coefficient, kp, can be determined using standard bench tests and captures the properties that govern a constituent＇s transformation when exposed to light. The development showed the photolysis coefficient to be equally useful for microbiological, inorganic and organic constituents. Values of kp calculated by the authors based on quantum yield and molar absorption coefficient data from the literature were summarized. Photolysis coefficients among microorganisms ranged from 8500 to more than 600000 and are far higher than for inorganic and organic compounds, which varied over a range of approximately 10 to 1000 and are much less sensitive to UV photolysis than the microorganisms.

关键词： UV photolysis disinfection advanced oxidation N-nitrosodimethylamine quantum yield absorption coefficient

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Photoluminescence from Silicon Nanocrystals in Encapsulating Materials

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Journal of Materials Science & Technology 2013年第3期29卷 221-224页

作者： Z.Deng X.D.Pi J.J.Zhao D.Yang State Key Laboratory of Silicon Materials and Department of Materials Science and Engineering Zhejiang University

Naturally oxidized freestanding silicon nanocrystals （Si NCs） are incorporated in commonly used encapsulating materials to explore the photoluminescent application of Si NCs in device structures such as solid-state lighting light-emitting diodes （LEDs） and solar cells. The quantum yield of Si NCs before the incorporation has reached about 45% at the excitation wavelength of 370 nm without any special surface modification. It is found that medium Ioadings, e.g., 5 wt% of Si NCs in encapsulating materials help to obtain high external quantum efficiency （EQE） of the mixtures of Si NCs and encapsulating materials. The curing of encapsulating materials significantly reduces EQE. Among all the encapsulating materials investigated in this work, silicone- OE6551 enables the highest EQE （21% at excitation wavelength λex = 370 nm） after curing. Based on current findings, we have discussed the continuous efforts to advance the photoluminescent application of Si NCs.

关键词： Photoluminescence Silicon nanocrystals Epoxy Silicone quantum yield External quantum efficiency

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Photonic properties of novel Yb3＋ doped germanium-lead oxyfluoride glass-ceramics for laser cooling applications

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Frontiers of Optoelectronics 2018年第2期11卷 189-198页

作者： Lauro J. Q. MAIA Jyothis THOMAS Yannick LEDEMI Kummara V. KRISHNAIAH Denis SELETSKIY Younes MESSADDEQ Raman KASHYAP Instituto de Fisica Universidade Federal de Goias Av. Esperanga 1533 Campus Samambaia Goiania GO 74690-900 Brazil Department of Electrical Engineering Ecole Polytechnique de Montrral P.O. Box 6079 Station Centre-ville Montreal QC H3C 3A7 Canada Department of Engineering Physics Ecole Polytechnique de Montrral P.O. Box 6079 Station Centre-ville Montreal QC H3C 3A7 Canada Centre d'Optique Photonique et Laser 2375 Rue de la Terrasse Universite Laval Qurbec QC G1V 0A6 Canada

Abstract In recent years, our research group has developed and studied new rare-earth doped materials for the promising technology of solid-state laser cooling, which is based on anti-stokes fluorescence. To the best of our knowledge, our group is the only one in Canada leading the research into the properties of nanoparticles, glasses and glass-ceramics for optical refrigeration appli- cations. In the present work, optical properties of 50GeO2- 30PbF2-18PbO-2YbF3 glass-ceramics for laser cooling are presented and discussed as a function of crystallization temperature. Spectroscopic results show that samples have near infrared photoluminescence emission due to the 2F5/2 - 2F7/2 Yb3＋ transition, centered at -1016 nm with an excitation wavelength of 920 nm or 1011 nm, and the highest photoluminescence emission efficiency occurs for heat-treatment for 5 h at 350℃. The internal photolumi- nescence quantum yield varies between 99% and 80%, depending on the temperature of heat-treatment, being the most efficient under 1011 nm excitation. The 2F5/2 lifetime increases from 1.472 to 1.970 ms for heat treatments at 330℃ to 350℃, respectively, due to energy trapping and the low phonon energy of the nanocrystals. The sample temperature dependence was measured with a fiber Bragg grating sensor, as a function of input pump laser wavelength and processing temperature. These measure- ments show that the heating process approaches near zero for an excitation wavelength between 1020 and 1030 nm, which is an indication that phonons are removed effectivelly from the glass-ceramic materials, and they can be used for optical laser cooling applications. On theother hand, the temperature increase as a function of input laser power into samples remains constant between 920 and 980 nm wavelength excitation, a temperature variation of 36 K/W （temperature of 58℃/W） was attained under excitation at 950 nm, showing a possible use for biomedical applications to be explored.

关键词： optical refrigeration oxyfluoride glass-cera-mics Yb3+ doping quantum yield infrared emission lifetime

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