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22 results on '"Qin, Jinlan"'

5. Rapid hydrothermal method for the preparation of carbon quantum dots in the presence of hydrogen peroxide

Author

Li Shanji, Chaofan Hu, Qin Jinlan, Bing-Fu Lei, Yuan Ningning, Chen Ying, and Yingliang Liu

Subjects
Photoluminescence, Materials science, Biomedical Engineering, Bioengineering, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Photochemistry, 01 natural sciences, Fluorescence, Hydrothermal circulation, 0104 chemical sciences, Nanomaterials, chemistry.chemical_compound, X-ray photoelectron spectroscopy, chemistry, Quantum dot, General Materials Science, 0210 nano-technology, Luminescence, Hydrogen peroxide
Abstract

Carbon quantum dots (CQDs) have been studied for years as one of the most promising fluorescent nanomaterials. Herein, CQDs were prepared rapidly by a simple, eco-friendly one-pot hydrothermal method in the presence of hydrogen peroxide. Different sizes of CQDs are obtained by changing the reaction time. X-ray photoelectron spectroscopy and Fourier transform infrared spectrometry demonstrated the existence of a large number of oxygen-containing groups on the surface of CQDs. The as-prepared CQDs exhibited bright yellow luminescence under UV light, they are applied for bioimaging of HeLa cells, and showed bright luminescence and excellent biocompatibility.

Published
2020

6. Synthesis, characterization and computational studies of Zn complex based on the 8-hydroxyquinoline group containing benzimidazole

Author

Yuan Ningning, Li Shanji, Xie Pengbo, Wang Zhengfang, Qin Jinlan, and Huawen Wen

Subjects
Benzimidazole, Materials science, Ligand, General Chemical Engineering, Infrared spectroscopy, chemistry.chemical_element, General Chemistry, Zinc, Fluorescence, Crystallography, chemistry.chemical_compound, chemistry, Excited state, Luminescence, Single crystal
Abstract

A novel fluorescent zinc complex with 8-hydroxyquinoline containing benzimidazole ligands has been designed and synthesized. Its emission, IR spectroscopy, thermo-gravimetric analysis as well as electrochemical properties have been studied. The solid-state structures were determined via single crystal X-ray diffraction and powder X-ray diffraction. It was found that the ligands around the Zn atoms are distorted by the constrained coordination environment. Computational studies have also been performed to provide insights into the electronic transitions, excited state origins and electrochemical properties of the complex. Based on the observed luminescence phenomena and the quantum chemical calculated results, it was also investigated that the energy transfer mechanism for the luminescence of the complex, which indicated that the ligand structural distortion could cause the blue shift in the emission profile of the complex.

Published
2020

16. Thermoluminescence and Temperature-Dependent Afterglow Properties in BaSi2 O2 N2: Eu2+.

Author

Qin, Jinlan, Zhang, Haoran, Lei, Bingfu, Hu, Chaofan, Li, Jinfang, Liu, Yingliang, Meng, Jianxin, Wang, Jing, Zheng, Mingtao, Xiao, Yong, and Hintzen, H.

Subjects
*PHOSPHORS, *PHOTOLUMINESCENCE, *THERMOLUMINESCENCE, *CHEMICAL stability, *LIGHT emitting diodes, *SPECTROPHOTOMETERS
Abstract

BaSi2 O2 N2: Eu2+ phosphor was successfully synthesized by using a simple solid-state reaction method. Its properties were systematically investigated utilizing XRD, photoluminescence, excited state decay curve, afterglow emission spectra, and thermoluminescence ( TL) glow curve. With increasing temperature, its emission intensity decreases with the broadening full widths at half maximum. Particularly, its temperature-dependent afterglow emission spectra were investigated for the first time. Based on the information from TL glow curve, temperature-dependent afterglow decay curves, and afterglow emission spectra, a model was constructed to explain the mechanism of afterglow. This study provides a new perspective to use the temperature-dependent luminescence properties for studying the afterglow processes of long-lasting phosphorescence phosphors. [ABSTRACT FROM AUTHOR]

Published
2013
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17. Thermoluminescence and Temperature-Dependent Afterglow Properties in BaSi2 O2 N2: Eu2+.

Author

Qin, Jinlan, Zhang, Haoran, Lei, Bingfu, Hu, Chaofan, Li, Jinfang, Liu, Yingliang, Meng, Jianxin, Wang, Jing, Zheng, Mingtao, Xiao, Yong, and Hintzen, H.

Subjects
PHOSPHORS, PHOTOLUMINESCENCE, THERMOLUMINESCENCE, CHEMICAL stability, LIGHT emitting diodes, SPECTROPHOTOMETERS
Abstract

BaSi2 O2 N2: Eu2+ phosphor was successfully synthesized by using a simple solid-state reaction method. Its properties were systematically investigated utilizing XRD, photoluminescence, excited state decay curve, afterglow emission spectra, and thermoluminescence ( TL) glow curve. With increasing temperature, its emission intensity decreases with the broadening full widths at half maximum. Particularly, its temperature-dependent afterglow emission spectra were investigated for the first time. Based on the information from TL glow curve, temperature-dependent afterglow decay curves, and afterglow emission spectra, a model was constructed to explain the mechanism of afterglow. This study provides a new perspective to use the temperature-dependent luminescence properties for studying the afterglow processes of long-lasting phosphorescence phosphors. [ABSTRACT FROM AUTHOR]

Published
2013
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18. Preparation of SrSi2 O2 N2: Eu2+ Phosphor by SrSi Alloy Precursor and Its Long-lasting Phosphorescence Properties.

Author

Zhang, Haoran, Lei, Bingfu, Qin, Jinlan, Li, Jinfang, Liu, Yingliang, Liu, Xiaotang, ZhENg, Mingtao, Xiao, Yong, Dong, Hanwu, and HintzEN, H.

Subjects
PHOSPHORS, ALLOYS, PHOSPHORESCENCE, CHEMICAL precursors, X-ray diffraction
Abstract

Oxynitride long-lasting phosphorescence ( LLP) phosphor SrSi2 O2 N2: Eu2+ was prepared by a new method using SrSi alloy as a precursor. Its properties were systematically investigated utilizing XRD, photoluminescence, excited-state decay curve, long-lasting phosphorescence, and thermoluminescence spectrum. This phosphor was found to be well-crystallized by calcinations of the Sr1− x Eu x Si alloy and the SiO2 mixture at 1400°C for 3 h. After irradiation under the 280 nm UV light, the afterglow emission of Eu2+ (4 f65 d1 → 4 f7) was obviously observed for at least 2 h in the limit of light perception of dark-adapted human eyes (0.32 mcd/m2). Furthermore, the possible mechanism for the LLP of SrSi2 O2 N2: Eu2+ phosphor is also discussed in this article. [ABSTRACT FROM AUTHOR]

Published
2013
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19. Temperature-Dependent Emission Spectra of Ca2 Si5 N8: Eu2+, Tm3+ Phosphor and its Afterglow Properties.

Author

Li, Jinfang, Lei, Bingfu, Qin, Jinlan, Liu, Yingliang, Liu, Xiaotang, and Heo, J.

Subjects
NITRIDES, PHOSPHORS, PHOSPHORESCENCE, LUMINESCENCE, AFTERGLOW (Physics), SINTER (Metallurgy)
Abstract

The nitrides Ca2 Si5 N8:0.5% Eu2+, x% Tm3+( x = 0, 0.5, 1, 2, 4) ( CSN:0.5E, xT) phosphors were prepared via the high temperature solid-sintering method using CaH2 as calcium source. These phosphors exhibited strong orange long-lasting phosphorescence ( LLP) after turning off the activating light. Besides, the CSN:0.5E, 1T phosphor with an afterglow time of more than 200 min (0.32 mcd/m2). Furthermore, the temperature-dependent emission spectra of CSN:0.5E, 1T were investigated from temperature 80-500 K and an anti-quenching phenomenon that the emission intensities increased then decreased under excitation at increased temperature was found. Ultimate, the proposed mechanism on temperature dependence of luminescence was analyzed. This study provides a new perspective for the impact of temperature-dependent problem as a consequence of heating processes in luminescent materials. [ABSTRACT FROM AUTHOR]

Published
2013
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20. Temperature-Dependent Luminescence Characteristic of SrSi2O2N2:Eu2+ Phosphor and Its Thermal Quenching Behavior.

Author

Qin, Jinlan, Hu, Chaofan, Lei, Bingfu, Li, Jinfang, Liu, Yingliang, Ye, Shuiping, and Pan, Miaozhu

Subjects
TEMPERATURE effect, LUMINESCENCE, RARE earth ions, QUENCHING (Chemistry), PHOSPHORS, CHEMICAL synthesis, SOLID state chemistry
Abstract

The yellow SrSi2O2N2:Eu2+ phosphor has been synthesized by using a simple solid-state reaction method with Sr2SiO4:Eu2+ as the precursor. It shows a broad excitation band extending from 250 to 520 nm and an asymmetric emission band with a main peak at about 550 nm. The emission intensity of the SrSi2O2N2:Eu2+ is about 1.2 times higher than the commercial yellow phosphor YAG:Ce3+ (P46-Y3). The temperature-dependent luminescence characteristic of SrSi2O2N2:Eu2+ has been investigated in this paper. With increasing temperature, the emission band of SrSi2O2N2:Eu2+ shows anomalous blue-shift along with decreasing emission intensity and the broadening full width at half maximum (FWHM). Particularly, compared with YAG:Ce3+ (P46-Y3), the yellow SrSi2O2N2:Eu2+ phosphors exhibit higher thermal stability due to their weaker electron-phonon coupling strength (1.1), lower stokes shift (0.0576 eV) and larger activation energy (0.288 eV). All these results indicate that SrSi2O2N2:Eu2+ yellow phosphors have potential application for white light-emitting diodes (LEDs). What's more, an energy level scheme is constructed to explain the anomalous blue-shift phenomenon. [Copyright &y& Elsevier]

Published
2014
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21. Luminescence Properties of High-Quality Ca2Si5N8: Eu2+ Phosphor: CaH2-Raw Material

Author

Li, Jinfang, Zhang, Haoran, Wang, Peng, Lei, Bingfu, Qin, Jinlan, Liu, Yingliang, Xiao, Yong, Zheng, Mingtao, and Meng, Jianxin

Abstract

Using cheaper CaH2 as calcium sources and an efficient reductant, red emitting phosphors (Ca1-xEux)2Si5N8 (x = 0.002, 0.005, 0.008, 0.01, 0.02 [?] 0.09) were prepared under 1540degC via the traditional solid-state reaction method. The photoluminescence characteristics with various Eu2+-doping concentrations were investigated. A broad excitation spectrum is full with a range of 200[?]600 nm. Broad band emissions and a high absorption were achieved and the emission peaks shifted from 603 to 617 nm with increased Eu2+ concentration. A large emission tunability and a high solubility of activators (a 14 nm red-shift at x = 0.09) make the obtained phosphors excellent candidates for LED conversion phosphors. With increasing Li3N concentration, the small particles gradually grow into well-crystallized and well-dispersed particles with a mean size of 5 um. The additive of Li3N is helpful to improve the uniformity and coarsening of Ca2Si5N8: Eu2+ particle.

Published
2013

22. Luminescent properties of green long-lasting Ca8Mg(SiO4)4Cl2:Eu2+, from Ca2SiO4:Eu3+ and MgCl2 at low temperature.

Author

Li, Jinfang, Zhang, Haoran, Lei, Bingfu, Qin, Jinlan, Liu, Yingliang, Xiao, Yong, Zheng, Mingtao, and Sha, Lei

Subjects
*LUMINESCENCE, *LOW temperatures, *EUROPIUM, *DOPED semiconductors, *METAL ions, *MAGNESIUM chloride, *DIOPSIDE
Abstract

Abstract: Eu2+-doped calcium magnesium chlorosilicate, Ca8Mg(SiO4)4Cl2:Eu2+ (CMSC:Eu2+), exhibited excellent green long-lasting performance, was synthesized via a modified solid-state reaction method using a precursor Ca2SiO4:Eu3+ and MgCl2. The effect of excess amount of MgCl2 on the crystal structure and the effects of a flux CaF2 on enhancing luminescence have been investigated. The thermoluminescent (TL) glow curve of CMSC:Eu2+ can be decomposed into three Gaussian profiles with peaks centered at 350K, 370K, and 432K, indicating that there are at least three different traps in CMSC:Eu2+ phosphor. The temperature-dependent emission spectra of CMSC:Eu2+ were also investigated. The quenching temperature of CMSC:Eu2+ is 400K and its activation energy can be calculated to be 0.3eV, which is close to the general value. Additively, the mechanism about the temperature-dependent PL was discussed. This study continued our research to provide a new perspective for the impact of temperature-dependent problem as a consequence of heating processes in luminescent materials. [Copyright &y& Elsevier]

Published
2013
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