CRYSTAL RESEARCH AND TECHNOLOGY
·
2022
·Vol. 57
·期 4
·2100162
·
IF 1.599
Yanli Ding,Zhaohan Li
The low luminous efficiency of upconversion materials limits their practical applications in various fields. The present study focuses on the efficient upconversion enhancement of β-NaYF 4 :Yb,Er induced by Bi 3+ doping. The XRD and SEM results show that introducing Bi 3+ into the matrix lattice changes the microstructure and particle size of the crystal. The photoluminescence spectra show that at 6% Bi 3+ doping, the red and green emission intensities are enhanced by 12 and 8 times, respectively. The reason could be the lattice distortion caused by Bi 3+ doping, breaking the partial forbidden transition of rare-earth ions. The fluorescence lifetime measurement reveals that the Bi 3+ doping changes the environment around erbium ions, affecting the energy level lifetime of erbium ions, explaining the luminescence dynamics law. The present study provides a facile route to achieve nano/microstructures with intense upconversion luminescence with potential applications in optoelectronic devices.
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
·
2023
·
IF 6.2
Shaokun Ling,Xiaoyan Qin,Chang chen,Kai Meng,Yifeng Yan,Junyun Ming,Sen Liao,Yingheng Huang,Lei Hou
Despite long-term development of LEDs, problems urgent to resolve is still existing. The most outstanding problem to tackle is luminescent stability at high temperature working situation. In this study, a novel type of β-NaYF 4 based phosphor incorporated with Eu 3+ and Tb 3+ is reported. A series of β-NaYF 4 :0.065Eu 3+ , x Tb 3+ ( x = 0.001, 0.002, 0.003, 0.004, 0.005) phosphors were synthesized by hydrothermal method . The sample β-NaYF 4 :0.065Eu 3+ ,0.002Tb 3+ possesses optimal luminescent property at room temperature. The mechanism of energy transfer from Tb 3+ to Eu 3+ ion is quadrupole-quadrupole interactions. The sample β-NaYF 4 :0.065Eu 3+ ,0.002Tb 3+ demonstrates zero thermal quenching (ZTQ) property at 303 K to 383 K. According to XRD and XPS characterizations, nonequivalent replacement between intrinsic ion Na + and Y 3+ were discovered, which finally leads to production of crystal defects. According to electron paramagnetic resonance (EPR) characterization and density functional theory (DFT) calculation, the type of crystal defect of β-NaYF 4 :0.065Eu 3+ ,0.002Tb 3+ is confirmed to be V Y vacancies which are the predominant defect of crystal. The depths and densities of defects were calculated according to data of thermoluminescence spectra (TL spectra). Crystal defects play the role of electrons traps that could store electrons. Electrons stored in traps will be excited to excitation state of Eu 3+ under the thermal stimulation to offset undesirable impact of thermal quenching (TQ), which leads to ZTQ property of the sample β-NaYF 4 :0.065Eu 3+ ,0.002Tb 3+ . The CRI and CCT of fabricated WLED are 3830 K and 84.1, respectively.
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 Physical Chemistry C
·
2020
·
IF 4.189
Yue Hu,Yanmin Yang,Xuefeng Zhang,Xin Wang,Xiaoxiao Li,Yunqian Li,Tianyi Li,Hongwu Zhang
Here, an X-ray-excited super-long afterglow phosphor β-NaYF4:Tb3+ has been discovered for the first time. After X-ray irradiation, the green emission can persist for more than 240 h. After 120 h, the power density of afterglow reached 3.76 × 10–6 W·m–2, which can be clearly observed by the naked eye under dark vision. Also, combined with the results of thermoluminescence and photoluminescence, the super-long afterglow emission of β-NaYF4:Tb3+ can be ascribed to the tunneling model associated with F centers. More importantly, the super-long green afterglow emission of β-NaYF4:Tb3+ has been successfully used as an in vivo light source to activate g-C3N4 for photodynamic therapy and bacteria destruction. Furthermore, super-long persistent luminescence of β-NaYF4:Tb3+ could be repeatedly charged by X-rays for many cycles, which indicates that the phosphors have high photostability under repeated cycles of alternating X-ray irradiation.
研究领域:
材料科学
·
医学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2014
·
IF 2.726
Chuanying Wang,Xianhua Cheng
Using a facile hydrothermal method , hexagonal β-NaYF 4 :Yb 3+ 20 mol%, Er 3+ 1 mol% crystals with predictable size and morphology were synthesized and the upconversion (UC) luminescence properties were investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectra were used to characterize the samples. The results indicated that the size and morphology of the crystals can be precisely controlled by tuning the pH values of the initial reaction solution and the molar ratio of NaNO 3 to RE 3+ (RE = Y + Yb + Er), and the mechanism was proposed. The UC luminescence properties of β-NaYF 4 :Yb 3+ /Er 3+ crystals were found to strongly depend on the crystal morphologies and sizes. The peak area ratio of green to red (R/G) increased from 0.29 to 1.03 with pH values increasing from 3 to 10, and increased from 1.03 to 1.26 with the increase of molar ratio of NaNO 3 to RE 3+ from 0 to 90. The emission colors were tuned from pure green to orange yellow. This study provides a facile way to synthesize β-NaYF 4 :Yb 3+ /Er 3+ crystals with predictable morphology and size, and tunable luminescence properties, which can be applicable for other rare earth fluoride compounds.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2016
·Vol. 3
·期 8
·1082-1090
·
IF 4.532
Min Li,Xiaoyang Liu,Li Liu,Bing Ma,Benxian Li,Xudong Zhao,Wenming Tong,Xiaofeng Wang
A series of Yb3+/Tm3+ co-doped β-NaYF4 (β-NaYF4:Yb,Tm) crystals have been successfully synthesized via the molten salt synthesis (MSS) method. A unique strong green emission of Tm3+ was observed, which cannot be obtained by any other method. The red, green and blue (RGB) light emissions have been obtained simultaneously in the presence of a single activator (Tm3+). The influencing factors of crystal growth have been studied in detail, in order to understand the change of the transition probabilities of Tm3+. Subsequent studies indicate that the RGB light emissions of Tm3+ can be effectively tuned by varying the concentration of sensitizers (Yb3+ and Mn2+) and the reaction time. Consequently, the effective multicolor upconversion (UC) luminescence was obtained, especially a strong white light, which was not obtained in the β-NaYF4:Yb,Tm system earlier. To our knowledge, it is the first time that the UC properties in the β-NaYF4:Yb,Tm system have been investigated by altering the transition probabilities at the same energy level of Tm3+.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
ACS Omega
·
2018
·
IF 0
Wen Qi,Qian Wu,Joseph G. Shapter,Meng Duan,Sheng Yang,Guo Gao
Chirality, universal characteristics of nature, introduces asymmetry in synthetic materials. Revealing the microscopic asymmetry of macroscopically symmetric materials is the key to control the growth of chiral materials and give full play to their application potential. Materials for photon upconversion (UC) are of great interest for many applications owing to their anti-Stoke luminescence process, especially for chiral UC materials. For the preparation of UC materials, a tiny change in reaction parameters will lead to variations in morphology, phase components, and fluorescence intensity, as well as its chirality. Because of the strict reaction conditions for the formation of chiral UC materials, there are no reports of the successful synthesis of chiral UC materials. Therefore, a facile method for the controllable synthesis of chiral UC materials is highly desired. Herein, chiral-assembled hexagonal prisms of β-NaYF4:Er3+/Yb3+ microcrystals were synthesized to realize the smart manipulation of their morphology as well as a great improvement of the fluorescence efficiency. We proposed a three-stage doped β-NaYF4 crystal growth mechanism on mesoscale regulation, where the fluorescence enhancement principle of chirality was revealed. The enhancement of fluorescence efficiency of chiral UC materials endows their promising application in luminescent displays.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
MATERIALS RESEARCH BULLETIN
·
2018
·
IF 2.873
Zhangxu Chen,Ming-Lai Fu
To extend the activities of TiO 2 to the near infrared (NIR) region and to separate and recycle photocatalysts easily is vital for the high harvest of solar energy for sustainable society. The magnetic NIR activated Fe 3 O 4 @SiO 2 /β-NaYF 4 :Yb 3+ ,Tm 3+ /TiO 2 (FS/UC/T) composites have been synthesized by using the solvothermal method by adding Fe 3 O 4 @SiO 2 and Degussa P25 into the mixed solution of NaOH, ethanol, oleic acid, Re(NO 3 ) 3 and NH 4 F. Moreover, the obtained composites were explored for photocatalytic applications. It was found that FS/UC/T emit UV–vis light under irradiation of 980 nm laser and efficient energy transfer from β-NaYF 4 :Yb 3+ ,Tm 3+ to TiO 2 was verified. The photodegradation experiments for treating methylene blue (MB), rhodamine B (RhB), methyl orange (MO) and colorless phenol were carried out to evaluate the photocatalytic activities of the samples. The photodegradation rates reach 76.62%, 68.48%, 30.05% and 27.16% for MB, RhB, MO and phenol under irradiation of 980 nm laser, respectively, which suggested magnetic FS/UC/T composite is an advanced NIR-driven photocatalyst. Moreover, the magnetic photocatalyst showed easy separation and good stability in the recycled tests. It suggested a promising system to utilize the NIR energy for photocatalysis based on TiO 2 and to utilize the magnetic for separation of photocatalysts, which will contribute to practical environmental remediation in the future.
研究领域:
材料科学
·
环境科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Materials Express
·
2018
·Vol. 8
·期 3
·199-210
·
IF 1.597
Yang Ling,Wang Zhengxiang,Zhao Tian,Zhong Yunfei,Liu Yuejun
Due to unique optical properties and high information concealment, upconversion materials, with excellent luminescent properties and good water dispersibility, have received significant attention in many fields recently, particularly for packaging anti-counterfeiting. In a vast majority
of parameters, chelating ligands played an essential role in controlling the phase structure, morphology and surface characteristics of the upconversion materials, thus produced an effect on photoluminescent properties. Herein, we demonstrated a facile hydrothermal synthetic strategy of β-NaYF4
upconversion microcrystals using waterborne polyurethane (WPU) prepolymer as the ligand. In order to achieve high intensity, the WPU polymer was prepared through molecular design and optimized preparation process, and the influence of WPU prepolymer with different ammonia contents on the luminescence
property of the crystals was investigated thoroughly. The results of powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) indicated that the as-prepared NaYF4
crystal possessed hexagonal phase structure, a forked rod shape, high crystallinity and excellent crystal quality. Interestingly, the crystal capped with WPU prepolymer possessed good water dispersibility and its fluorescence intensity at 540 nm was 10∼15 times as higher as that of the
crystal chelated with trisodium citrate (TSC) or ligand-free. The possible reasons have been proposed. It was demonstrated that the β-NaYF4 (Er3+/Tm3+, Yb3+/Er3+ or Yb3+/Tm3+ co-doped) crystals capped
with WPU prepolymer would be promising candidates to prepare waterborne RGB anti-counterfeit inks which were eco-friendly and suitable for stamping designable patterns and handwriting on flexible packaging substrates. The patterns and handwritings were invisible under ambient conditions, while
displayed bright multicolor fluorescence upon 980 nm irradiation, which confirmed that the as-prepared crystals exhibited high potential in packaging anti-counterfeiting.
研究领域:
材料科学
·
光学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2016
·Vol. 52
·期 2
·869-877
·
IF 2.302
Fan Shaohua,Wang Shikai,Xu Wenbin,Li Meng,Sun Hongtao,Hu Lili
Efficient upconversion (UC) microcrystals are important for the development of novel photonic markers, solid-state lasers, displays, etc. Herein, we report on greatly enhanced UC emission in β-NaYF 4 :20Yb,2Er microcrystals via a simple ion-exchange reaction. The ion exchange accompanying with an ionic redistribution process is demonstrated. By simply controlling the amount of NaF (0–8.0 mmol), reaction temperature (140–220 °C), and duration (0–144 h), enormous enhancement of the UC emission up to ~4200 times is obtained compared with the pre-synthesized β-NaYF 4 :20Yb,2Er microcrystals. The decrease of body defects and change of local structure around lanthanide may account for the UC emission enhancement. This method may apply to other UC materials to increase the UC emission efficiency.
研究领域:
材料科学
·
光子学
·
纳米技术
·
无机化学
·
发光材料
✓ 已验证
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2013
·Vol. 15
·期 35
·14681-14688
·
IF 3.829
Xingyuan Guo,Weiye Song,Changfeng Chen,Weihua Di,Weiping Qin
A novel near-infrared (NIR)-responsive photocatalyst, β-NaYF4:Yb3+,Tm3+@ZnO composites, was prepared by a two-step high temperature thermolysis method. In the NIR-responsive photocatalysis, β-NaYF4:Yb,Tm served as a NIR-to-UV upconverter and provided “UV light” or “necessary energy” to the ZnO catalyst. The energy transfer in the composites and the mixtures of β-NaYF4:Yb,Tm and ZnO was studied by using steady-state and dynamic fluorescence spectroscopy. The NIR photocatalytic activities were investigated by the decomposition of Rhodamine B. It was found that the energy transfer processes dominated the overall photocatalytic activities, and the generation of hydroxyl radicals was the origin of organic pollutant decomposition under NIR irradiation.
研究领域:
材料化学
·
光催化
·
纳米材料
·
环境化学
·
无机化学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 38
·10226-10232
·
IF 5.976
M. Yuan,R. Wang,C. Zhang,Z. Yang,W. Cui,X. Yang,N. Xiao,H. Wang,X. Xu
Exploiting new transitions in the visible light range is important in the development of advanced color displays, superior laser materials, and novel optical devices. Here, for the first time, we observed several intensive upconversion (UC) emission bands at 382, 472, 506, 560, and 618 nm from a single β-NaYF4:Yb/Er microcrystal via saturated excitation. Compared to the traditional red (650 nm) and green (545 nm) UC emissions, these new emission bands intensify rapidly as the excitation intensity increases, which leads to full-color UC luminescence in the visible region. Nearly white luminescence was elicited from a single microcrystal with a relatively high excitation power. Moreover, the mechanism of these newly observed UC emissions was elucidated by examining the energy migration. It was also found that these microcrystals exhibit waveguide-transmission characteristics and are transparent to their own UC emissions. These findings provide a basis for further exploration of the silent transitions of other rare-earth-ions and demonstrate the potential for using β-NaYF4:Yb/Er microcrystals in a variety of applications in color display and waveguide-based optical devices.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Materials Science and Engineering B-Advanced Functional Solid-State Materials
·
2020
·
IF 4.706
Hao Tang,Ying Xu,Xianhua Cheng
To investigate the optical properties of rare earth upconversion particle, the Cr 3+ and alkaline-earth ions (Mg 2+ or Ca 2+ ) co-doped β-NaYF 4 :Yb 3+ /Er 3+ upconversion microparticles (UCMPs) were synthesized via a facile hydrothermal method . The influences of co-doping ions and their concentrations on crystal structure, particle morphology and optical properties were thoroughly investigated by XRD , SEM , FT-IR spectra, UV–VIS-NIR absorption spectra and photoluminescence spectra. And the effects of the two kinds of impurity ions co-doping on the UC particle growth were studied. We found that luminescence quenching could be inhibited by using Cr 3+ and Mg 2+ co-doping due to the asymmetrical ion arrangement around activator. However, the Cr 3+ and Ca 2+ co-doping was found to quench the upconversion luminescence (UCL), and the possible mechanism was suggested. These discoveries lead to new insights into the quenching effect and new strategy to design UCMPs for better luminescence performance.
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）