JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Xin Chen,Linwen Jiang,Luhui Zhou,Mingyu He,Jiangtao Li,Anhua Wu,Hongbing Chen
The Er 3+ @Yb 3+ co-doped SrAl 2 B 2 O 7 phosphors were prepared by a sol-gel auto-combustion method. The components, microstructure and up-conversion (UC) properties of samples were investigated systematically. The phosphors emitted red light and green light under the excitation of 980 nm wavelength. The intensity of red emission and green emission nearly linearly decreased with increasing ambient temperatures. The red emission, green emission and their intensity ratio as a function of Er 3+ concentrations and Yb 3+ concentrations were studied in detail. The results show that 4.0% Er 3+ and 8.0% Yb 3+ doped samples can obtain the best luminescence intensity while the best light purity cannot be obtained simultaneously. The intensity of red and green emission was measured as a function of excitation power. It indicates that there was no photon avalanche mechanism for SrAl 2 B 2 O 7 : Er 3+ @Yb 3+ due to the absence of sharp change of n values. The UC luminescence corresponded to a two-photon absorption process which was illustrated by the energy transfer mechanism and the steady-state rate equations. Because of the controllable monochromatic luminescence and excellent temperature-dependent luminescence properties, the SrAl 2 B 2 O 7 : Er 3+ @Yb 3+ phosphors have potential application in the fields of non-contact temperature measurement and bio-polychromatic label.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2021
·Vol. 11
·期 12
·3310
·
IF 5.076
Yijie Xia,Shuaishuai Du,Pengju Huang,Luchao Wu,Siyu Yan,Weizhi Wang,Gaoyu Zhong
The temperature-dependent photoluminescence (PL) properties of an anti-perovskite [MnBr4]BrCs3sample in the temperature range of 78–500 K are studied in the present work. This material exhibits unique performance which is different from a typical perovskite. Experiments showed that from room temperature to 78 K, the luminous intensity increased as the temperature decreased. From room temperature to 500 K, the photoluminescence intensity gradually decreased with increasing temperature. Experiments with varying temperatures repeatedly showed that the emission wavelength was very stable. Based on the above-mentioned phenomenon of the changing photoluminescence under different temperatures, the mechanism is deduced from the temperature-dependent characteristics of excitons, and the experimental results are explained on the basis of the types of excitons with different energy levels and different recombination rates involved in the steady-state PL process. The results show that in the measured temperature range of 78–500 K, the steady-state PL of [MnBr4]BrCs3had three excitons with different energy levels and recombination rates participating. The involved excitons with the highest energy level not only had a high radiative recombination rate, but a high non-radiative recombination rate as well. The excitons at the second-highest energy level had a similar radiative recombination rate to the lowest energy level excitons and a had high non-radiative recombination rate. These excitons made the photoluminescence gradually decrease with increasing temperature. This may be the reason for this material’s high photoluminescence efficiency and low electroluminescence efficiency.Keywords:[MnBr4]BrCs3;temperature-dependent;photoluminescence;excitons
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED PHYSICS
·
2022
·Vol. 132
·期 3
·
IF 2.877
Guo Heng,Zhu Yizhi,Chen Jinping,Xie Xiaoyu,Jiang Qingsong,Xu Chunxiang,Cui Qiannan,Shi Zengliang
As an effective means to endow lead halide perovskite nanocrystals (NCs) with new properties, ion doping has been widely applied. Transition metal Mn-doped CsPbCl 3 is of particular interest, as the Mn doping introduces new emission bands, improves photoluminescence quantum yield (PLQY), and even enhances stability. However, it is still insufficient to catch insight of the energy transfer process and luminescence characteristics of these high defect tolerance NCs doped with Mn ion. Here, we systematically studied the energy transfer from exciton to Mn 2+ ions in Mn-doped CsPbCl 3 NCs by variable temperature steady-state fluorescence spectra and time-resolved spectra. The abnormal attenuation behavior of the exciton and Mn 2+ with the change of temperature was observed, from which we predict the existence of shallow traps near the conduction band and these shallow traps will affect the luminescence properties by influencing the energy transfer process. We show a simple physical model invoking only shallow trap states that uniquely describe the temperature-dependent energy transfer between the exciton and the Mn 2+ ion. The thermometric performance (30–290 K) was studied in terms of relative thermal sensitivity, in which the calculated relative sensitivity range is ∼0.12%–1% K −1 .
研究领域:
材料科学
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光学
✓ 已验证
产品关联
DOI
高影响因子
ACTA PHYSICO-CHIMICA SINICA
·
2013
·Vol. 29
·期 10
·2157-2161
·
IF 0.869
LI Chang-Ping,LI Zhuo,ZOU Ben-Xue,LIU Qing-Shan,LIU Xiao-Xia
The density, viscosity, and conductivity of protic ionic liquid (PIL) N,N-dimethylethanolammonium propionate (DMEOAP) were determined in the temperature range of 283.15-333.15 K. The influence of temperature on density, viscosity, and conductivity is discussed. The thermal expansion
coefficient, molecular volume, standard molar entropy, and lattice energy of DMEOAP were calculated using empirical and semiempirical equations. The molar conductivity of DMEOAP was determined fromdensity and conductivity data. The temperature dependence of viscosity and conductivity data
was fitted using the Vogel-Fulcher-Tammann (VFT) equation. The relationship between molar conductivity and viscosity was determined by the Walden rule.
研究领域:
化学
·
物理化学
✓ 已验证
DOI
PubMed
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2019
·Vol. 30
·期 6
·1906232
·
IF 15.621
Rudai Zhao,Nan Ma,Kai Song,Ya Yang
BiFeO 3 (BFO) is a potentially important Pb-free ferroelectric with a narrow bandgap and is expected to become a novel photodetector. The photocurrent in BFO 3 strongly depends on the temperature but only a few studies have investigated in detail the relationships between photocurrent and temperature. Here, the temperature-dependent photocurrent and the corresponding photosensing properties of a Ag/BFO/indiumtin oxide (ITO) photodetector based on an optimized planar-structured electrode configuration are investigated. The photocurrent and responsivity of the BFO 3 -based photodetector can first be increased and then be decreased with increasing temperature. The largest photocurrent and responsivity can reach 51.5 µA and 6.56 × 10 −4 A W −1 at 66.1 °C, which is enhanced 126.3% as compared with that at room temperature. This may be caused by the temperature-modulated bandgap and barrier height in Ag/BFO/ITO device. This study clarifies the relationship between photosensing performance and the operating temperature of BFO-based photodetector and will push forward the application of ferroelectric materials in photoelectric field.
研究领域:
材料科学
·
光电领域
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2019
·Vol. 48
·期 22
·7910-7917
·
IF 4.052
Xue-Ying Wu,Qi Zhao,Dong-Xue Zhang,Ya-Chuan Liang,Kui-Kui Zhang,Qian Liu,Lin Dong,Chong-Xin Shan
Luminescent hybrid materials based on nanodiamonds (NDs) and rare earth ions have been successfully synthesized by covalently modifying NDs with pyromellitic acid (PMA) which is capable of coordinating to Eu3+ and Tb3+ ions. With NDs acting as a host matrix, the PMA and rare earth ions serve as an organic sensitizer and activator, respectively, yielding a highly bright hybrid composite. Interestingly, for the co-doped hybrid composites ND-PMA-Eu/Tb, the intensity ratio of the two emissions, 5D4 → 7F5 transition (Tb3+) to 5D0 → 7F2 transition (Eu3+), is linearly related to temperature in the range from 77 K to 277 K. Therefore, the hybrid could be developed as a self-calibrated ratiometric luminescent thermometer due to its temperature-dependent luminescence performance.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Physical Chemistry C
·
2020
·
IF 4.189
Keisei Shibata,Jiyu Yan,Yuji Hazama,Shaoqiang Chen,Hidefumi Akiyama
This is the first study of lead halide perovskites (LHPs) that compares the coupling strengths between longitudinal optical (LO) phonons and free or localized excitons. In this research, we measured the excitation density and temperature dependence of the photoluminescence (PL) spectra in the range of 4-300 K in a CsPbBr3 single crystal. The PL peak energy of the free excitons monotonically blueshifts when the temperature increases, and so does the localized excitons until the temperature reaches 80 K. Above 80 K, however, the PL peak energy of the localized excitons redshifts when the temperature increases. We analyzed this unique temperature dependence using the configuration coordinate model, focusing on the exciton - LO phonon interaction. We showed that this unique temperature dependence can be exhibited as the localized excitons couple with the LO phonons with enhanced strength and have larger relaxation energy than the free excitons.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2025
·
IF 7.3
Changzu Zhu,Tao Jiang,Shilin Jiang,Xinyu Zhang,Ming Cheng,Wentao Zhou,Wei-qun Shi,Yafei Wang
Electrochemical separation of spent fuel utilizing molten salt as a medium is an efficient approach to achieve the sustainable development of nuclear energy. The Lewis acidity and basicity of molten salts are closely related to the local structure of the molten salt and significantly influence its properties. In this study, the acidity–basicity scales of LiCl–KCl–CsCl–LaCl3 molten salts have been quantitatively determined using in situ UV–vis spectrophotometry with Tl+ probes, and the relationship between the acidity–basicity scale and temperature was deduced. The influence of molten salt’s acidity–basicity scale on its structural evolution was investigated through Deep Potential Molecular Dynamics (DPMD) simulations and in situ Raman spectroscopy. As the acidity–basicity scale of molten salt increases, the short-range ordering of the melt diminishes, and the intermediate-range ordering enhances. Moreover, based on the accumulation of data at various temperatures, the relationships between the temperature-dependent acidity–basicity scale and the thermal transport properties were derived. The reduction potential of La was analyzed through electrochemical tests to evaluate the corrosiveness of the salt melt, and it was found that molten salt with a higher acidity–basicity scale exhibited greater corrosivity. This study elucidates the correlation of the acidity–basicity scale with salt structure and properties, providing an effective method for comprehensive assessment and real-time monitoring of salt structure and properties through the direct measurement of the salt acidity–basicity scale.
研究领域:
核能化学
·
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Qiang Xu,Wenyi Shao,Xinlei Zhang,Jun Liu,Xiaoping Ouyang,Xiaobin Tang,Wenbao Jia
Organic-inorganic halide perovskite (OIHP) has attracted tremendous attention due to its potential applications in optoelectronics such as light emitting device and photodetector . Here, we have grown high quality CH 3 NH 3 PbBr x Cl 3-x perovskite single crystals and investigated the luminescence mechanism of these materials. The results indicate that optical properties of CH 3 NH 3 PbBr x Cl 3-x perovskite materials are strongly depend on the temperature and the dope concentration. Free exciton recombination emission has dominant contribution to luminescence spectra of materials at orthorhombic structure, as bound exciton recombination emission to the spectra of materials at cubic structure. Based on temperature-dependent photoluminescence , the exciton binding energy of CH 3 NH 3 PbCl 3 and CH 3 NH 3 PbBr 0.3 Cl 2.7 are calculated as about 22.9 meV and 27.1 meV, respectively.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Chinese Physics B
·
2017
·Vol. 26
·期 6
·067804
·
IF 1.223
Qi Ding,Xiao-Song Zhang,Lan Li,Jian-Ping Xu,Ping Zhou,Xiao-Fei Dong,Ming Yan
Colloidal ZnAgInSe (ZAISe) quantum dots (QDs) with different particle sizes were obtained by accommodating the reaction time. In the previous research, photoluminescence (PL) of ZAISe QDs only could be tuned by changing the composition. In this work the size-tunable photoluminescence was observed successfully. The red shift in the photoluminescence spectra was caused by the quantum confinement effect. The time-resolved photoluminescence indicated that the luminescence mechanisms of the ZAISe QDs were contributed by three recombination processes. Furthermore, the temperature-dependent PL spectra were investigated. We verified the regular change of temperature-dependent PL intensity, peak energy, and the emission linewidth of broadening for ZAISe QDs. According to these fitting data, the activation energy (ΔE) of ZAISe QDs with different nanocrystal sizes was obtained and the stability of luminescence was discussed.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2017
·
IF 6.32
Yin Yu,Yongxin Tao,Baozhu Yang,Datong Wu,Yong Qin,Yong Kong
A quinine (QN)-based chiral sensing platform with alterable enantioselectivity is constructed for electrochemical chiral recognition of tryptophan (Trp) isomers. The electrochemical signals of l- and d-Trp on the QN modified electrode depend closely on temperature, and more particularly are reversed at certain temperatures, which could be attributed to the temperature-sensitive H-bonds and π–π interactions between QN and the Trp isomers. The mechanisms of the reverse chiral recognition are investigated by density functional theory (DFT), variable-temperature UV spectra, and variable-temperature 1H NMR spectra. In addition, the chiral recognition is highly specific to the isomers of Trp compared with other chiral amino acids. This study is the first example showing how temperature influences the reverse recognition of electrochemical chiral interfaces.
研究领域:
生物化学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF ANALYTICAL CHEMISTRY
·
2021
·
IF 1.134
Yong-Sheng NIU,Li-Xin SUN,Cong-Wei HU,Jin-Hao ZHOU,Qiang DOU,Qing-Nuan LI
The fluorination behavior of molybdenum (Mo) powder with NF 3 , such as temperature dependence of reactivity, reaction mechanism and kinetics were investigated on a homemade fluoride volatility process (FVP) research device. The in-situ Fourier transform infrared (FTIR) spectroscopy was applied to determine the beginning and the end of reaction. The research demonstrated that near 500 K or lower, the reaction between Mo power and NF 3 occurred, meanwhile, the temperature had an important influence on the average reaction rate and the utilization of NF 3 . When the temperature increased from 500 K to 700 K, the average rate increased from 1.04 × 10 –2 mol/h to 2.40 × 10 –2 mol/h and the utilization of NF 3 increased from 21.2% to 49.0%. The in-situ FTIR and XRD analysis assisted by thermodynamic calculation indicated that Mo power was converted to MoF 6 through an intermediate product MoF 3 : 2NF 3 (g) + 2Mo (s) = 2MoF 3 (s) + N 2 (g), then 2MoF 3 (s) + 2NF 3 (g) = 2MoF 6 (g) + N 2 (g). Based on a mathematical model with unreacted shrinking core, the calculated reaction rate constant increased from 1.77 × 10 –2 min –1 to 3.48 × 10 –2 min –1 in the temperature range of 500–700 K, and the activation energy was 10.13 kJ/mol.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
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