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991.
Fuqiang Ren 《Powder Technology》2009,194(3):187-113
Using urea, boric acid and polyethylene glycol (PEG) as auxiliary reagents, the novel red emitting phosphors (Sr0.85Zn0.15)3(PO4)2:Eu3+ have been successfully synthesized by a modified solid-state reaction. The material has potential application as a fluorescent material for ultraviolet light-emitting diodes (UV-LEDs). The dependence of the properties of (Sr0.85Zn0.15)3(PO4)2:Eu3+ phosphors upon urea, boric acid and the PEG concentration and the quadric sintered temperature were investigated. The crystallization and particle sizes of (Sr0.85Zn0.15)3(PO4)2:Eu3+ have been investigated by using powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). Luminescent measurements showed that the phosphors can be efficiently excited by ultraviolet (UV) to visible region, emitting a red light with a peak wavelength of 616 nm. The results show that the boric acid, urea and the PEG were effective in improving the fluorescent intensity of (Sr0.85Zn0.15)3(PO4)2:Eu3+ and the optimum molar ratio was 0.1, 8 and 0.021, respectively. 相似文献
992.
Li Chen Xiao-Ming Lin Yin Ying Qing-Guang Zhan Ze-Hong Hong Jun-Yong Li Ng Seik Weng Yue-Peng Cai 《Inorganic chemistry communications》2009,12(8):761-765
Three new two-dimensional 3d–4f isostructural heterometallic coordination polymers, namely [Ln2Zn(2,3-pydc)4(H2O)4·4H2O]n (Ln = Sm (1), Eu (2), Gd (3), 2,3-pydcH2 = pyridine-2,3-dicarboxylic acid) have been successfully synthesized by the hydrothermal reactions of Ln2O3, Zn(NO3)2·6H2O, H2pydc and H2O. X-ray diffraction analyses reveal that they possess a 2D heterometallic framework containing 1D lanthanide chains based on dimeric [Ln(2,3-pydc)2(H2O)2]2 unit. The Zn(II) ion, which is six-coordinated by four oxygen and two nitrogen atoms from four 2,3-pydc2− ligands, as a bridge, links the lanthanide chains to make the 1D chains further extend into 2D layer framework. Furthermore, the neighboring layers are assembled into three-dimensional supramolecular network through inter-layer O–HO and C–HO hydrogen-bond interactions. In addition, the solid-state luminescent property of complex 2 was investigated. 相似文献
993.
Kun-Jiao Chen Hai-Bing Xu Li-Yi Zhang Zhong-Ning Chen 《Inorganic chemistry communications》2009,12(8):744-746
The preparation, characterization and photophysical properties of heterobinuclear complexes {Pt(C^N^N)(CCbpy)}Ln(hfac)3 (C^N^N = 2-(6-(naphthalen-3-yl)-4-phenylpyridin-2-yl)pyridine; HCCbpy = 5-ethynyl-2,2′-bipyridine; Ln = Nd, Eu, Yb; hfac = hexafluoroacetylacetonate) are described. With excitation at 390 λex 500 nm which is the MLCT/LLCT absorption region of the Pt(C^N^N)(CCbpy) chromophore, lanthanide luminescence is successfully attained by Pt → Ln energy transfer from the platinum(II) antenna chromophore to the lanthanide center across the bridging CCbpy ligand. 相似文献
994.
Yu Zhou Chaofan Zhong Yan He Lifen Xiao Yuan Liu Hailiang Zhang 《Journal of Inorganic and Organometallic Polymers and Materials》2009,19(3):328-334
Abstract A novel ligand, 2,7-bis[2-(2′-Pyridyl)benzimidazole]- 9,9′-dioctylfluorene (BPDOF) and its polymeric complexes with copper(II)
and zinc(II) were successfully synthesized and characterized by 1H NMR, FT-IR, elemental analysis, UV-vis, conductivity measurements and gel permeation chromatography. The UV–vis absorption,
fluorescence spectra, and thermal properties of these complexes were investigated at room temperature. The experimental results
show that polymeric metal complexes BPDOF-Cu(II) and BPDOF-Zn(II) emit purple/green luminescence at 430 and 509 nm in DMF
solution and emit green luminescence at 495 and 527 nm in the solid state. Thermal properties measurement and analysis show
that they have good thermal stabilities.
Graphical Abstract Synthesis route: 2,7-bis[2-(2′-Pyridyl) benzimidazole]- 9,9′-dioctylfluorene (BPDOF) was synthesized using 2-(2′-Pyridyl)benzimidazole
and 2,7-dibromo-9,9′-dioctylfluorene by Ullmann condensation. Polymeric metal complexes of the corresponding were synthesized
with CuCl2 · 2H2O, ZnCl2.
相似文献
995.
Sung Wook Mhin Jeong Ho Ryu Kang Min Kim Gyeong Seon Park Han Wool Ryu Kwang Bo Shim Takeshi Sasaki Naoto Koshizaki 《Nanoscale research letters》2009,4(8):888-895
Cerium-doped Tb3Al5O12 (TAG:Ce3+) colloidal nanocrystals were synthesized by pulsed laser ablation (PLA) in de-ionized water and lauryl dimethylaminoacetic
acid betain (LDA) aqueous solution for luminescent bio-labeling application. The influence of LDA molecules on the crystallinity,
crystal morphology, crystallite size, and luminescent properties of the prepared TAG:Ce3+ colloidal nanocrystals was investigated in detail. When the LDA solution was used, smaller average crystallite size, narrower
size distribution, and enhanced luminescence were observed. These characteristics were explained by the effective role of
occupying the oxygen defects on the surface of TAG:Ce3+ colloidal nanocrystal because the amphoteric LDA molecules were attached by positively charged TAG:Ce3+ colloidal nanocrystals. The blue-shifted phenomena found in luminescent spectra of the TAG:Ce3+ colloidal nanocrystals could not be explained by previous crystal field theory. We discuss the 5d energy level of Ce3+ with decreased crystal size with a phenomenological model that explains the relationship between bond distance with 5d energy
level of Ce3+ based on the concept of crystal field theory modified by covalency contribution. 相似文献
996.
A novel Bi-doped P2O5-B2O3-Al2O3 glass was investigated, and strong broadband NIR (near infrared) luminescence was observed when the sample was excited by 445 nm, 532 nm, 808 nm and 980 nm lasers, respectively. The max FWHM with 312 nm, the lifetime with 580 μs and the σemτ product with 5.3 × 10− 24 cm2 s were obtained which indicates that this glass is a promising material for broadband optical amplifier and tunable laser. The effect of the introduction of B2O3 on the glass structure and Bi-ions illuminant mechanism were discussed and analyzed. It is suggested that the introduction of B2O3 makes the glass structure closer, and the broadband NIR emission derives from Bi0:2D3/2 → 4S3/2 and Bi+:3P1 → 3P0 transitions. 相似文献
997.
RongfangWangYilin Wang Quanlong FengLiya Zhou Fuzhong GongYuwei Lan 《Materials Letters》2012,66(1):261-263
A novel approach has been developed to synthesize cysteamine (CA)-CdTe quantum dots (QDs) in an aqueous medium. Compared with previous reports, the proposed method involves a one-step synthesis using TeO2 to replace Te or Al2Te3 as tellurium source. The influences of the precursor Cd/Te molar ratios and the pH of the original solution on the quantum yield (QY) of the obtained CdTe QDs were investigated systematically. Green- to orange-emitting CdTe QDs, with a maximum photoluminescence QY of 10.73%, were obtained. X-ray powder diffraction and transmission electron microscopy were used to characterize the crystalline structure and shape of the materials. CdTe QDs with CA modification exhibit a zinc-blended crystal structure in a sphere-like shape. 相似文献
998.
Eu3+-doped (1% and 3%) γ-Ca3(PO4)2 was synthesized by high-pressure and high-temperature experimental method and the samples were characterized by X-ray diffraction. The luminescence properties of samples were investigated by emission and excitation spectra. The excitation spectra of Eu3+-doped γ-Ca3(PO4)2 showed that samples were mainly attributed to Eu3+–O2− charge-transfer band at 270 nm, and some sharp lines were also attributed to Eu3+ f–f transitions in near-UV regions with the strongest peaks at 395 nm. Under the 395 nm excitation, the intense red emission peak at 611 nm was observed. The strongest line (395 nm) in excitation spectra of those phosphors matched well with the output wavelength of UV InGaN-based light-emitting diodes (LEDs) chip. The luminescent properties suggested that Eu3+-doped γ-Ca3(PO4)2 might be regarded as a potential red phosphor candidate for near-UV LEDs. 相似文献
999.
Zinc oxide (ZnO) is a versatile material that has been used in photocatalysis, solar cells, chemical sensors, and piezoelectric transducers. All these are directly related to its surface properties. Here ZnO nanorod arrays were successfully synthesized by electrochemical deposition method, the surface of which was modified by dopamine, a robust anchor. Compared with pristine ZnO sample, the surface modification can greatly enhance the ultraviolet and visible-light photoluminescence. This is due to the formation of polydopamine on the nanorod surface, which may act as a dye that can be photoexcited. The resultant photogenerated electrons can inject into the conduction band of ZnO and take part in the luminescent process. These results may provide a foundation for real applications of ZnO nanomaterials in optoelectronic devices and, especially, for the applications in biological field as both the dopamine and ZnO are biocompatible materials. 相似文献
1000.