JOURNAL OF RARE EARTHS
·
2015
·
IF 1.261
Mengting LI,Baoxiang JIAO
ZnTiO 3 :Eu 3+ phosphors were synthesized with different concentrations of Eu 3+ doping through sol-gel method. The samples were calcined at different temperatures for 2 h in air. The synthesized powders were characterized by X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), transmission electron microscopy (TEM), Raman and photoluminescence spectroscopy. The XRD results showed that the ZnTiO 3 :Eu 3+ phosphors doped with different concentrations of Eu 3+ ions calcined at 600 °C were of single phase, which indicated that the Eu 3+ ions had been successfully incorporated into the ZnTiO 3 host lattice and did not destroy the lattice structure of ZnTiO 3 host. The Raman spectrum, SEM and TEM also proved that the doping of Eu 3+ did not change the lattice structure of hexagonal ZnTiO 3 host. The photoluminescence (PL) of Eu 3+ ions with the main emission peak at 614 nm was observed to increase with Eu 3+ concentrations from 0.5 mol.% to 2.0 mol.% and decreased when the concentration was increased to 2.5 mol.%. The decrease in the PL intensity at higher Eu 3+ concentrations could be associated with concentration quenching effect. The CIE1931 chromaticity diagram ( x , y ) of ZnTiO 3 :2.0 wt.%Eu 3+ phosphors were located in the red region ( x =0.652, y =0.347). The luminescence properties suggested that ZnTiO 3 :Eu 3+ phosphors might be regarded as a potential red phosphor candidate for light emitting diodes (LEDs).
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
VACUUM
·
2021
·
IF 3.627
Tong Xue,Yiyi Shi,Jie Guo,Meixian Guo,Ya Yan
Water soluble AgInS 2 quantum dots (AIS QDs) were successfully prepared by an environmentally friendly one-pot water phase method using glutathione (GSH) as the stabilizing agent. The crystal structure, morphology, size, chemical states, and optical properties of as-prepared AIS QDs were characterized through X-ray diffraction (XRD), Scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometer (FTIR), Ultraviolet–visible spectrophotometer (UV–vis) and Photoluminescence spectrometer (PL). Factors affecting the fluorescence intensity of AIS QDs including reaction solution pH value, fluorescence test temperature and concentration of AIS QDs were investigated. The fluorescence stability of AIS QDs and the selectivity of AIS QDs toward Pb 2+ detection was also evaluated. Under optimized test conditions, three excellent linear relationships ( ( F 0 − F ) / F 0 = 27.938 C P b 2 + − 0.002 ( R = 0.998 ) , ( F 0 − F ) / F 0 = 10.362 C P b 2 + − 0.005 ( R = 0.997 ) , ( F 0 − F ) / F 0 = 6.554 C P b 2 + − 0.240 ( R = 0.9993 ) were achieved between the concentration of Pb 2+ and the relative fluorescence quenching amount of AIS QDs in the range of 9–96 nM, 48–434 nM and 193–530 nM, respectively. The detection limit was 4 nM and the recovery was in the range of 92.2%–102.6%. Our method had wide detection range, excellent selectivity, high sensitivity and easy operability, and could be applied for the content determination of Pb 2+ in water. The possible fluorescence quenching mechanism of AIS QDs by Pb 2+ was discussed in detail and the dynamic quenching mechanism of light-induced electron transfer was put forward.
研究领域:
材料科学
·
环境科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Leipeng Li,Feng Qin,Yuan Zhou,Yangdong Zheng,Hua Zhao,Zhiguo Zhang
In this field of luminescence ratiometric thermometry, it is long believed that those thermally coupled energy levels (TCELs) spaced by the approximate gaps own similar relative sensitivities ( Sr ), when the expression Sr = ΔE / kT 2 is taken into consideration, where ΔE is the gap between TCELs, k the Boltzmann constant , and T the absolute temperature. We demonstrate it is, however, inaccurate to some extent. The 653/678 nm emission bands and the 523/543 nm ones of Er 3+ , capable of enabling the thermal sensing over the temperature scope between 303 and 753 K, own similar practical gaps. However, the relative sensitivity for the 523/543 nm TCELs is much larger than that for the 653/678 nm ones. The former and the latter Sr are 0.88 and 0.18% K −1 at 303 K, respectively, which largely differs from the conventional conception. The intense thermal quenching effect imposed on the 4 F 9/2 state is verified to be responsible for this abnormal phenomenon. Due to the severe depopulation effect, the 653/678 nm TCELs’ emitting intensity ratio is confirmed to reflect more the thermal quenching mechanism but less the thermal effect. We then use the steady state rate equations to qualitatively show how the competition between the thermalization controlled by the Boltzmann distribution and the non-radiative relaxation mechanism plays a key role in determination of the final relative thermal sensitivity.
研究领域:
物理学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2017
·
IF 2.686
Xiaoming Xie,Jie Chen,Yanhua Song,Xiuqing Zhou,Keyan Zheng,Xiangting Zhang,Zhan Shi,Haifeng Zou,Ye Sheng
Zn 2 SiO 4 :Eu 3+ phosphors with diverse morphologies, including rice-like, hexahedron-like, and column-like, have been successfully prepared by means of a simple hydrothermal approach followed by a subsequent calcinations process. The results indicate that the morphologies of the products can be adjusted by altering the pH value of the reaction system. The formation mechanisms of different morphologies of samples have been investigated in detail. Furthermore, under near ultraviolet excitation, the Zn 2 SiO 4 :Eu 3+ exhibits strong red emission corresponding to the 5 D 0 → 7 F 2 transitions of the Eu 3+ ions, which have potential applications in optical and biological areas. Meanwhile, luminescent characteristics of different morphologies have been explored and the column-like Zn 2 SiO 4 :Eu 3+ sample presents an optimum red luminescence. The CIE chromaticity diagram and the symmetry of the different morphologies phosphors also have been explored. In addition, the concentration quenching effects and decay kinetics behaviors of Zn 2 SiO 4 :Eu 3+ microstructures with optimum red luminescence were investigated and the strongest luminescent intensity and the longest lifetime were both in the composition of 0.03 mol Eu 3+ .
研究领域:
材料科学
·
光学
·
生物应用
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2022
·
IF 5.436
Xibao Zhang,Liang Zhang,Yonghui Xu,Xiudi Wu,Shuwen Yin,Chuansheng Zhong,Hongpeng You
For inorganic luminescent materials with activators, the energy yield is usually observed to decrease with an increase in activator concentration, which is known as the concentration quenching effect. To inhibit this phenomenon, a common strategy is to increase the distance between activators. Most previous reports have focused on the three-dimensional crystal lattice, and there have been few reports about two-dimensional layered structure. Herein, we synthesized a novel Cr3+-activated near-infrared (NIR) phosphor Li2Sr2Al(PO4)3 (LSAPO) with layered structure, and in such a two-dimensional structure, we proved experimentally that the concentration quenching was suppressed. Under 460 nm excitation, LSAPO:Cr3+ gave a broad NIR emission band (700–1200 nm) centered at 823 nm with a full width at half-maximum (fwhm) of 178 nm and a broad absorption band, indicating its potential application in NIR spectroscopy. Moreover, by codoping Cr3+ and Yb3+ ions, we further widened the emission bandwidth to ∼230 nm of fwhm, the internal quantum efficiency increased from 54% to 61%, and the thermal stability was improved. The fabricated NIR device with a LSAPO:Cr3+,Yb3+ phosphor coupled with blue chips can be applied in night-vision technologies and medical fields.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2020
·
IF 3.408
Hanjun Zhang,Furong Tao,Yuezhi Cui,Hongtao Wu
Fluorescent conjugated polymers are widely used for trace detection of explosives due to their super-quenching effect. In this work, a hyper-branched conjugated polymer P2 and a linear conjugated polymer P1 were synthesized. Compared with P1, P2 showed the superior sensitivity toward 2,4,6-trinitrophenol (PA). The Stern-Volmer constants ( K sv ) of P2 (1.56 × 10 4 M −1 ) was 2.7 times higher than that of P1 (0.57 × 10 4 M −1 ), and the LODs to PA of P2 (8.8 μM) was 3.2 times lower than that of P1 (24 μM). These data indicated the enhanced super-quenching effect in P2. Due to the electrons transfer among the conjugated backbone of polymer, the super-quenching effect of P1 with one-dimensional (1D) configuration may be defined as “length quenching”, while that of P2 with two-dimensional (2D) configuration can be defined as “Area quenching”. The 2D conjugation nature of P2 provided multi migration channel for excitons , which resulted in the remarkably enhanced super-quenching.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
COLLOID AND POLYMER SCIENCE
·
2017
·Vol. 295
·期 12
·2383-2393
·
IF 1.723
Zhang Mengmeng,Si Xiaowei,Jiang Dehao,Yang Xinlin,Lu Yan,Shen Yinghua
Functional polymer microspheres with fluorescent carbazole unit and various functional groups, such as amide, pyridyl, and imidazole, were prepared by distillation precipitation copolymerization of divinylbenzene (DVB) as a crosslinker, N-vinylcarbazole (NVCz), together with acrylamide (AAm), 4-vinylpyridine (VPy), and 1-vinylimidazole ((VIM) as functional monomers in acetonitrile in the absence of any stabilizer. The resultant polymer microspheres were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy, photoluminescent spectroscopy, inductively coupled plasma (ICP), and X-ray photoelectron microscopy (XPS). The functional polymer microspheres acted as a “turn-off” chemical sensor with excellent stability for determination of copper cation (Cu 2+ ) in methanol via the quenching effect of fluorescence after adsorption of Cu 2+ from the solution through the capture ability of functional groups, such as pyridyl, imidazole, and amide on the surface of polymer microspheres. A good linear relationship was set up between the photoluminescence intensity at the emission peak of 352 nm and the Cu 2+ concentrations ranging from 0 to 1.0 μM with the presence of pyridyl group as a ligand. The effects of the functional groups were investigated on the fluorescent response for the microspheres as chemical sensors.
研究领域:
材料科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2021
·Vol. 17
·期 45
·2103424
·
IF 13.281
Huan Gao,Xuan Wei,Meize Li,Lei Wang,Tianxiang Wei,Zhihui Dai
Exploring new electrochemiluminescence (ECL) luminophores to construct high-efficiency sensing systems is always a hot direction for developing ECL sensors. Compared with other luminophores, metal–organic frameworks (MOFs) exhibit high mass transfer ability for accelerating the reactivity in its pore channels, which is conducive to improving the performance of ECL sensors. In this work, La 3+ -BTC MOFs (LaMOFs) are prepared as the highly active reactor and novel ECL luminophore. On this basis, a novel co-quenching effect mechanism is proposed based on double-stranded DNA (dsDNA) triggered cooperation between LaMOFs and crystal violet (CV) molecules. Under the confined pore channels of LaMOFs, CV can play an important role as the photon-acceptor due to the matched absorption spectrum with the ECL spectrum of LaMOFs, and the electron-acceptor on account of its lowest unoccupied molecular orbital level. Based on the proposed co-quenching effect mechanism, a constructed ECL gene sensor shows good assay performance toward p53 gene in the detection range of 1 p m to 100 n m with a detection limit of 0.33 p m . The co-quenching effect integrating LaMOFs with CV is expected to be a versatile approach in the construction of ECL gene sensor, which has good prospect in expanding the application range of ECL technology.
研究领域:
分析化学
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Haoli Ji,Xiaoru Dai,Wenyan Zheng,Chen Zhuang,Wenkun Dong,Dong Chen,Shisheng Ling,Xvsheng Qiao,Zhiyu Wang,Xianping Fan,Guodong Qian
Lanthanide-doped upconversion nanoparticles excel in many fields of applications due to their unique anti-Stokes spectroscopic properties, narrow emission bands, and high photochemical stability. Yb-based self-sensitized fluorides nanoparticles have higher absorption efficiency at 980 nm near-infrared laser than Y-based nanoparticles. This enhanced absorption makes NaYbF 4 an outstanding upconversion host material for pumping more photons to high-energy excited states of Tm 3+ that are rich in energy levels. For these purposes, NaYbF 4 :Tm nanoparticles seem to be more favorable for photoluminescence applications. In this study, size-adjustable NaYbF 4 :Tm nanoparticles were prepared using a high-temperature co-precipitation method. Under 980 nm excitation, the upconversion emission spectra appeared four emission bands in visible region. By increasing the size of nanoparticles, we well enhanced upconversion luminescence, indicating that surface quenching sites play a major role in inhibiting upconversion luminescence. In addition, the negative thermal quenching effect of NaYbF 4 :Tm nanoparticles was observed with temperature dependent luminescence spectra, and we found that smaller sized nanoparticles got stronger negative thermal enhancement and better temperature sensing performance. We fitted the luminescence intensity ratio (LIR) between the 1 D 2 → 3 F 4 (451 nm) and 1 G 4 → 3 F 4 (647 nm) transitions of Tm 3+ , where these nanoparticles exhibited both good absolute sensitivity S A (1.38% K −1 , at 453 K) and relative sensitivity S R (2.56% K −1 , at 293 K). These results suggested that NaYbF 4 :Tm nanoparticles could be a good candidate for thermometers even at high temperatures (up to 500 K).
研究领域:
材料科学
·
光学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2016
·
IF 4.758
Bing Zheng,Yan Li,Furong Tao,Yuezhi Cui,Tianduo Li
Carbazole-based linear conjugated polymer (P 1 ) and hyperbranched conjugated polymer (P 2 ), were successfully synthesized with high molecular weights and good solubilities through Sonogashira coupling reactions. Compared with P 1 , the charactyeristics of P 2 were remarkably changed by exhibiting outstanding thermal stabilities and different emission behaviors. In this work, a superquenching effect was observed in the TNT-detection process by using P 2. The calculated Stern-Volmer quenching constant revealed that P 2 was more sensitive than P 1 towards TNT in solution, owing to the hyperbranched structure of P 2 had multiple exciton migration channels and diffusion pathways via numerous branches in the two-dimensional (2D) space. Simultaneously, quenching efficiency of P 2 was higher than that of P 1 , due to hyperbranched structure of P 2 had multiple exciton migration channels.
研究领域:
材料科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2019
·Vol. 30
·期 12
·11419-11428
·
IF 2.195
Zhao Caiyue,Xu Yudong,Wang Lei,Chen Xinyi,Hu Wenjie,Dai Zhaoxiang,Hu Mengyuan,Liu Kai,Shi Min
In this study, Bi 3+ and Mn 4+ co-doped CaAl 12 O 19 phosphors were prepared via high-temperature solid-state reaction method, and their crystal structure, particle morphologies, luminescence properties, charge compensation mechanism and crystal field effect were investigated in detail. A most remarkable tuning effect can be achieved when the Bi 3+ concentration is 5% in CaAl 12 O 19 :Bi 3+ , 0.05% Mn 4+ and the electric multipolar interaction is inferred to be the main mechanism for concentration quenching effect. It is also found that, as charge compensators rather than sensitizers, Bi 3+ ions can effectively tailor the emissions in a wide range through partial reducing Mn 4+ to Mn 2+ . The charge compensation physics presumably involves the shift of Fermi energy level ( E F ) and variations of valence states of manganese ions after Bi 3+ introduction. Moreover, the authors calculated the splitting energy (Δ) and Racah parameters ( B and C ) for Mn 4+ in octahedral sites and Mn 2+ in tetrahedral sites by combining excitation spectra with Tanabe-Sugano diagram. The experimental results will be of certain helpfulness in developing phosphors used in white LED.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Zehua Tian,Beichen Liu,Yang Xiao,Zihao Wang,Lizhen Zhang,Shijie Xu,Honggang Ye,Kangzhen Tian,Xinming Nie,Fei Tang
In this study, we report a unique solution-combustion synthesis of Mn 4+ doped CaYAlO 4 microcrystals and demonstrate a narrow-band deep-red emission. Through the simulation of low-temperature photoluminescence (PL) spectroscopy and theoretical fitting on temperature-dependent PL intensity at T < 400 K, we obtained a dominant phonon mode with energy of 40 meV during the vibronic coupling process, with a small Huang-Rhys factor of S = 0.68. From the analysis of the measured PL lifetime evolution of Mn4 + doped CaYAlO 4 , it is found that luminescence thermal quenching effect was mainly attributed to four-dominant phonon interaction with Mn 4+ electronic states. More interestingly, the deviation of luminescence decay curve from the single-exponential mode at T > 400 K suggests that the occurrence of two radiative transitions is a consequence of ionically thermal excitation to the second excited state of 4 T 2 . These findings provide not only a general approach to identify the predominant phonon vibration, but also deep insights into the effect of weak electron-phonon coupling on PL properties of solid-state luminescent.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）