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luminescence modulation of ultrasmall gold clusters by aromatic ligands

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Nano Research 2023年第8期16卷 11366-11374页

作者： Xue-Jing Zhai Jia-Hua Hu Jianxin Guan Yubing Si Xi-Yan Dong Peng Luo Fangfang Pan Zhihao Yu Runping Han Shuang-Quan Zang College of Chemistry Zhengzhou UniversityZhengzhou 450001China College of Chemistry and Chemical Engineering Henan Polytechnic UniversityJiaozuo 454003China College of Chemistry and Molecular Engineering Peking UniversityBeijing 100871China College of Chemistry Central China Normal UniversityWuhan 430079China

luminescence is one of the most important properties for metal nanoclusters;however,clearly revealing its origin remains *** different luminescence properties of the two prototypical 8e nanoclusters Au_(11)and Au_(13)remain elusive—Au_(11)is always nonluminescent,whereas Au_(13)is *** this work,by using a designed unique aromatic ligand(quinoline-2-thiol),we obtained new atomically precise phosphine-thiolate-protected neutral Au_(11)-SH and cationic Au_(13)-*** comparison with the classic phosphine-halide-protected Au_(11)-Cl and Au_(13)-Cl,the Cl-to-thiol alteration triggered room-temperature luminescence of the Au_(11)core and dramatically modulated that of the Au_(13)*** ultraviolet/infrared(UV/IR)spectroscopy,which is sensitive to organic aromatic groups,together with ultrafast transient absorption(TA)spectroscopy unprecedently revealed a relaxation process from the ligand to core state affecting the dynamics in excited states and some critical intermediate states favouring efficient room-temperature emission of these *** work provides some new insights into the origin of photoluminescence of metal nanoclusters and opens an avenue to modulate the dynamics of their excited states using aromatic ligands,which would have direct applications in lighting,light harvesting,and photocatalysis.

关键词： metal nanoclusters luminescence ligand modification

luminescence investigation of Dy2O2S and Dy2O2SO4 obtained by thermal decomposition of sulfate hydrate

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Journal of Rare Earths 2016年第8期34卷 814-819页

作者： R.V.Rodngues L.Marciniak L.U.Khan J.R.Matos H.F.Brito W.Strek Institute of Chemistry University of Sao Paulo Butanta 748 26077 Sao Paulo Brasil Institute of Low Temperature and Structure Research University of Wroctaw Oko1na 250-422 Wroclaw Poland

The yellow emitting dysprosium oxysulfide （Dy2O2S） and dysprosium oxysulfate （Dy202SO4） compounds were prepared from the thermal decomposition of hydrated dysprosium sulphate. The materials were characterized by using thermogravimetry （TG/DTG）, X-ray powder diffraction （XRD）, Fourier transform infrared （FTIR） and Raman spectroscopies. The thermal stability temperatures at around 1151 and 1313 K were determined for the Dy202S and Dy202SO4 materials, respectively. The photolumines- cence properties of the dysprosium oxysulfide were investigated, showing narrow emission bands assigned to the 4F9/2----＊6HJ intracon- figurational transitions of the Dy3＋ ion. The yellow emission color of this phosphor suggests that the Dy202S is a promising material for applications in LEDs.

关键词： Dy202S/Dy202SO4 sulfate thermal decomposition luminescence rare earths

luminescence characteristics of Dy^(3+) doped Gd_2O_3-CaO-SiO_2-B_2O_3 scintillating glasses

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Journal of Rare Earths 2016年第6期34卷 583-589页

作者： J.Kaewkhao N.Wantana S.Kaewjaeng S.Kothan H.J.Kim Center of Excellence in Glass Technology and Materials Science (CEGM) Nakhon Pathom Rajabhat University Department of Radiologic Technology Faculty of Associated Medical Sciences Chiang Mai University Department of Physics Kyungpook National University

Glasses were prepared from the compositions of 25Gd_2O_3-10 CaO-10 SiO_2-（55–x）B_2O_3-xDy_2O_3（where x is 0.0 mol.%–1.0 mol.%） by the conventional melt-quenching technique at 1400 oC. The results demonstrated the increase in the glass density with respect to the increase in the doping concentrations of Dy_2O_3. Nine absorption bands were observed. The emission spectra of the developed glass showed two strong peaks at 577 nm（~4F_（9/2）→~6H_（13/2）） and 482 nm（~4F_（9/2）→~6H_（15/2））. The highest emission intensity was observed from the developed glass prepared at 0.4 mol.% of Dy_2O_3, as the efficient energy transfer took place from Gd^（3＋） to Dy^（3＋）. From the X-ray induced optical luminescence, the emission spectra were identical to those from PL measurements, but with the highest intensity observed from the glass quenched at 0.45 mol.% of Dy_2O_3. Finally, the integral scintillation efficiency of the developed glass was determined at 27% of that of the commercially available BGO crystal.

关键词： amorphous materials glasses oxides optical properties luminescence rare earths

luminescence properties of rare earth complexes bonded to novel mesoporous spherical hybrid materials

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Journal of Rare Earths 2023年第1期41卷 60-66页

作者： Lin Huang Juan Wang Haipeng Zhang Guannan Zu Zhentao Wang Yonghong Fu Shaanxi Key Laboratory of Nanomaterials and Nanotechnology Xi'an University of Architecture and TechnologyXi'an 710055China

YVO_(4):Eu^(3+) phosphors have been widely used in optoelectronic integration fields of its chemical and thermal ***,the excitation spectrum band of VO_(4)^(3-) is too narrow for high-efficiency luminescence,restricting its further ***,flower-like and linear-like YVO_(4):Eu^(3+) hollow mesoporous spheres were synthesized and connected with Eu organic ligand,to obtain a new hybrid luminescent *** characterization shows that the pores of microspheres are in size of about 2-50 nm,sticked with regular morphology,well crystallized,and in uniform *** emission intensity of hybrid luminescent material is higher than that of single YVO_(4):Eu^(3+) and single Eu co mplexes realizing the purpose of mutually reinforcing luminesce *** paper provides a new idea to connect rare earth complexes for a new non-silicon-based mesoporous spherical matrix.

关键词： YVO_(4):Eu^(3+) Mesoporous spheres Hybrid material luminescence Rare earths

luminescence of Er^(3+) in Oxyfluoride Transparent Glass-Ceramics

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Journal of Rare Earths 2006年第6期24卷 699-705页

作者： Akira Ueda Steven H Morgan Richard Mu Department of Physics Fisk University NashvilleTN 37208 USA

Erbium doped silicate, germanate, and tellurium-germanate oxyfluoride glasses were prepared in a bulk form. Through appropriate heat treatment of the as-prepared glasses, transparent glass-ceramics （TGCs） were obtained with the formation of β-PbF2：Er^3＋ nanocrystals in the glass matrix were confirmed by X-ray ***-defined diffraction peaks were observed in the samples after heat-treatment. The average crystal diameter of these precipitated crystals from full-width at half-maximum （FWHM） of the diffraction peak was estimated to be between 8 and 13 nm. Optical absorption, photoluminescence, and upconversion luminescence were measured on as-prepared glass and glass-ceramics. luminescence spectra in the TGC samples revealed well-resolved, sharp stark-splitting peaks, which indicates that a majority of Er^3＋ ions has been incorporated into the crystalline phase of the nanocrystals. The intensity of the visible and near infrared luminescence mostly increases in TSG compared to that in the as-prepared glass. In 1.53 μm absorption and emission bands, the maximum absorption peak is blue-shifted from 1531 to 1507 nm, whereas the maximum emission peak is redshifted from 1535 to 1543 nm in TGC, as compared with that in glass. The bandwidth at half-maximum （BWHM） of the emission band is significantly broader in TGC than in glass, which is beneficial to the erbium-doped fiber amplifier （EDFA）. Upconversion luminescence was measured using 800 nm near-infrared light excitation. Drastically increased upconversion 1 was observed from the TGC as compared to that from their corresponding as-prepared glasses. In addition to a strong green emission centered at 545 nm because of ^4S3/2→^4I15/2 transition and a weaker red emission centered at 662 nm because of ^4F9/2→^4I15/2 transition, generally seen from the Er^3＋ doped glasses, two violet emissions centered at 410 nm because of ^2H9/2→^4I15/2 transition and centered at 379 nm because of ^4G11/2→^4I15/2 transition were also o

关键词： luminescence transparent glass-ceramics rare earths

luminescence properties of Eu^(3+):NaGd(WO_4_)2 nanoparticles and nanorods

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Journal of Rare Earths 2016年第2期34卷 118-124页

作者：王烨青唐界琴黄新阳江亮 School of Science East China Jiaotong University Institute of Research on the Functional Materials Jiangxi University of Finance and Economy

The NaGd(WO4)2:Eu3+ phosphors were prepared by the microemulsion mediated hydrothermal method. The morphology and size of the samples could be dependent on the pH in the initial solution. These phosphors obtained had a strong absorption at 395 nm matching with the popular emission of near-UV LED chips, and could emit intense red light at 616 nm. The small ellipsoid-like particles or short rods were provided with large parameters of oscillator strength?2 and asymmetry ratio. Compared to the ellip-soid-like phosphors, the rod-like phosphors took on stronger emission, longer lifetime and larger quantum efficiency. This work demonstrated that the one-dimension NaGd(WO4)2:Eu3+ phosphors might be a more favorable device than zero-dimension ones for photoluminescence.

关键词： microemulsion mediated hydrothermal method NaGd(WO4)2:Eu3+ red phosphors luminescence rare earths

luminescence study of europium(III) tris(β-diketonato)/phosphonate complexes in chloroform

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Journal of Rare Earths 2008年第2期26卷 185-191页

作者： Stefan Lis Zbigniew Piskula Krzysztof Staninski Sayaka Tamaki Masayuki Inoue Yuko Hasegawa Department of Rare Earths Faculty of Chemistry Adam Mickiewicz University Grunwaldzka 6 Department of Chemistry Faculty of Science Science University of Tokyo

The extraction of Eu（Ⅲ） with β-diketone, HA, and monodentate or bidentate Lewis bases, B, into chloroform and the luminescence properties of the extracted species were studied. Pivaloyltrifluoroacetone, Hpta, and 2-thenoyltfifluoroacetone, Htta, were used as the β-diketones. The Lewis bases, B, were tetraethyl methylene diphosphonate, POPO, which was bidentate, and diethyl benzylphosphonate, PhPO which was monodentate. Based on the extraction data, the stability constants, log β, of the first complexes between tfis（β-diketonato）Eu（Ⅲ） and the phosphonate, EuA3B, were determined to be 6.0 for the POPO complex and 3.40 for the PhPO complex. The Eu（Ⅲ） luminescence intensity in the EuA3POPO was larger than EuA3 where A was either pta or tta at similar concentrations of Eu（Ⅲ）, while that in Eu（pta）3PhPO was stronger than EuA3; however, in Eu（tta）3PhPO, it was weaker than Eu（tta）3. The POPO functions as a sensitizer, and the PhPO functions as a quencher for the tta chelate and as a sensitizer for the pta chelate. From the lifetime and quantum yield, φ, of the Eu（Ⅲ） luminescence in the complexes as well as the observation of the extractability of Eu（Ⅲ） with the Hpta and the phosphonates and of the luminescence spectra of the complexes, it was confirmed that the extraction of Eu（Ⅲ） was remarkably enhanced with a β-diketonate and a strong Lewis base, and also the ternary complex that was formed as the extracted species, showed luminescence enhancement. This phenomenon may be due the formation of a strong bond between the Eu（Ⅲ） and the strong Lewis base leading to more hydrophobicity in the extracted species and also to more effective energy transfer from the Lewis base to the Eu（Ⅲ）. It was not significant whether the donor atoms were N or O.

关键词： tris(β-diketonato)Eu(Ⅲ) extraction luminescence phosphonate ligands rare earths

luminescence of emission-tunable Na_(15.6)Ca_(3.84)Si_(12)O_(36):Ce^(3+),Tb^(3+),Na^+phosphors for near-ultraviolet light-emitting diodes

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Journal of Rare Earths 2016年第6期34卷 565-570页

作者：张佳俞阿龙华正和温世正 School of Physics and Electronic Electrical Engineering Huaiyin Normal UniversityHuai'an 223001China Jiangsu Provincial Key Laboratory of Mod-ern Measurement Technology and Intelligent System Huai'an 223001China

A series of Na_（15.6）Ca_（3.84）Si_（12）O_（36）：Ce^（3＋）,Tb^（3＋）,Na~＋（NCS：Ce^（3＋）,Tb^（3＋）,Na~＋） phosphors were prepared by conventional solid-state reaction method, and their photoluminescence properties under near-ultraviolet（NUV） excitation were studied. The excitation spectrum of Ce^（3＋）-single-doped NCS showed a broad excitation band from 250 to 400 nm, which could well match with the emission wavelength of the NUV LED chip. Upon 365 nm excitation, the NCS：Ce^（3＋）,Na~＋ phosphor demonstrated a blue emission in the range of 400–600 nm with the predominated peak at 443 nm. By co-doping Tb^（3＋） into NCS：0.04Ce^（3＋）,0.04Na~＋, tunable-emission was realized due to the energy transfer from Ce^（3＋） to Tb^（3＋）, and nearly white light was also obtained. The investigation also revealed that warm white light could be further generated by combining the NCS：0.04Ce^（3＋）,y Tb^（3＋）,（0.04＋y）Na~＋ with other red-emitting phosphors. Thus, the NCS：Ce^（3＋）,Tb^（3＋）,Na~＋ phosphors could be promising candidate for white LEDs.

关键词： luminescence phosphor light-emitting diodes rare earths

luminescence and magnetic properties of bifunctional nanoparticles composited by nitrogen-doped graphene quantum dots and gadolinium

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Journal of Rare Earths 2024年第4期42卷 716-723页

作者： Wanli Zhang Hao Zhou Meigui Ou Donghao Sun Chunlin Yang College of Materials and Metallurgy University of GuizhouGuiyang550025China National Local Co-construction Engineering Laboratory for High Performance Metal Structure Material and Manufacture Technology Guiyang550025 China College of Chemistry and Materials Engineering Guiyang UniversityGuiyang550003China

In this paper,nitrogen-doped graphene quantum dots(N-GQDs)were combined with gadolinium ions(Gd^(3+))by a surface modification to obtain magneto-optical dual-functional N-GQDs/Gd^(3+)*** morphology of obtained composite was characterized by field emission scanning electron microscopy and transmission electron *** and magnetic properties were measured by a fluorescence spectrophotometer and a vibrating sample magnetometer,*** indicate that well-dispersed spherical N-GQDs/Gd^(3+)nanoparticles have an average diameter of 7 nm.N-doping significantly increases the luminesce nce of particles with an optimal luminescence intensity at 20℃and pH=9.X-ray photoelectron spectroscopy results indicate that the N-doping introduces pyrrolic N as an electron donor,enhancing fluorescence by increasing the surface electron cloud density of *** addition,density functional theory calculation results reveal that N-doping reduces the band gap of NGQDs/Gd^(3+),enabling electronic transitions to higher energy levels and generating more activation sites,thereby enhancing *** to N-GQDs/Gd^(3+)prepared at 20℃,the saturated magnetization of particles prepared at 40℃is 0.85 emu/g,indicating a better magnetic *** above results suggest that bifunctional nanomaterials N-GQDs/Gd^(3+)with excellent optical properties and magnetism can be better used for fluorescence and magnetic resonance imaging.

关键词： Nitrogen-doped graphenequantum dots Gadolinium luminescence Magnetism Rare earths