ISRAEL JOURNAL OF CHEMISTRY
·
2015
·Vol. 56
·期 4
·242-248
·
IF 2.221
Junwei Zhao,Jian Wu,Junfei Xue,Qiannan Zhu,Weihai Ni
Graphical Colloidal superparticles (SPs) are nanoparticle (NP) assemblies in the form of colloidal particles. Assembling nanoscopic objects into mesoscopic or macroscopic composite architectures allows for the bottom-up fabrication of functional nanomaterials. In this study, a method for single-step self-assembly synthesis of Au/NaYF 4 : Yb,Er SPs was developed using oil-in-water (O/W) microemulsions to simultaneously encapsulate gold nanoparticles (AuNPs) and NaYF 4 : Yb,Er upconversion nanoparticles (UCNPs) via evaporation at room temperature. The synthesized Au/NaYF 4 : Yb,Er SPs possess good dispersibility and stability. When the number of AuNPs added is increased, the SPs exhibit decreased upconversion luminescence, which can be ascribed to the Förster resonance energy transfer (FRET) from the NaYF 4 : Yb,Er UCNPs to the AuNPs. Time-resolved measurements of the green emission further confirm the existence of a new decay route corresponding to the FRET process. Our research provides a facile and versatile strategy for the synthesis of novel multifunctional nanocomposites with tunable upconversion luminescence properties, which can be of great significance in biological applications.
研究领域:
材料科学
·
纳米技术
·
光学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2019
·
IF 6.361
Xiaokai Xu,Xuejie Zhang,Chaofan Hu,Wei Li,Bingfu Lei,Yingliang Liu,Jianle Zhuang
The combination of carbon dots (CDs) and rare-earth ions has attracted increasing attention due to their unique fluorescence properties. Herein, CDs are incorporated with NaYF 4 :Eu to form stable NaYF 4 :Eu@CDs nanocomposites by a simple sol-gel route. It has been demonstrated that CDs are successfully embedded in the silica layer outside NaYF 4 :Eu nanoparticles. These nanocomposites exhibit characteristic emissions of both CDs and NaYF 4 :Eu under a single excitation wavelength. By using their dual-emissive properties, the nanocomposites can act as ratiometric fluorescent sensor for selective detection of Fe 3+ ions in the range of 0–350 μM. The temperature-dependent luminescent property of the nanocomposites makes them also suitable as thermometers in the range from 377 to 467 K. In addition, the luminescent color can be regularly adjusted by tuning the mass ratio of NaYF 4 :Eu to CDs. This combing strategy enables us to achieve dual emission of CDs and Eu 3+ ions in nanocrystals, opening an avenue towards multifunctional applications in widespread fields.
研究领域:
材料科学
·
分析化学
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Nano Materials
·
2020
·
IF 0
Chunyu Qi,Li Chen,Yuan Gao,Yue Wang,Jing Li,Ligong Zhang,Yongshi Luo,Xiaojun Wang
Size and size distribution control along with the excitation/emission wavelength manipulation are the most indispensable for both fundamental research and applications of upconverting nanophosphors. In contradiction to the usual Ostwald ripening process, digestive ripening-mediated growth of core–shell nanostructures is observed in a lanthanide-doped ternary fluoride system. Time-dependent size evolution of NaYbF4:Tm@NaYF4 nanoparticles is systematically investigated, and a Ksp-involved growth mechanism is proposed to better understand this unusual phenomenon. The upconversion luminescence (UCL) intensity and branch ratio of near-infrared to visible emission (NIR/VIS) dramatically increase due to the NaYF4 coating but subsequently undergo a decline when an additional SiO2 layer grows outside. As a comparison, an alternant type of core–shell–shell nanostructure, NaYbF4:Tm@SiO2@NaYF4, is further constructed, in which both the UCL intensity and NIR/VIS ratio exhibit an inverse trend. The comparative analysis on the basis of steady and transient spectroscopic data from NaYbF4:Tm, and alternatively coated by silica and NaYF4 nanoshells, respectively, demonstrates that the UCL properties can be regulated through core–shell engineering once the optical behavior of the surface states can be manipulated. The results provide a promising alternative strategy to fabricate a uniform core–shell nanostructure with multicompositions, and this NIRin–NIRout luminescent profile deserves an expectable vision for the subsequent clinical applications of UCL imaging for deep biological tissues.
研究领域:
材料科学
·
生物医学工程
·
光学
✓ 已验证
产品关联
DOI
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
POWDER TECHNOLOGY
·
2012
·
IF 2.08
Wanyue Shao,Ruinian Hua,Wei Zhang,Yue Tian,Jun Zhao,Liyan Na,Jicheng Yu,Zhengang Sun
Carboxylic acid-functionalized Yb 3 + /Er 3 + co-doped α - and β -NaYF 4 nano-/micro-spheres were prepared through a simple poly(acrylic acid) (PAA)-assisted hydrothermal process. Bovine serum albumin (BSA) protein was conjugated with Yb 3 + /Er 3 + co-doped α -( β -)NaYF 4 upconversion phosphors via free carboxylic acid groups on the surface of phosphors. The final products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), infrared (IR) spectrophotometer, ultraviolet (UV) spectrophotometer and photoluminescence spectroscopy (PL). XRD results showed that pure α -NaYF 4 :Yb 3 + , Er 3 + nanospheres could be obtained via PAA assisted hydrothermal process at the pH value of 4–5 and 160 °C for 1–4 h. The obtained product is a mixture of α and β phases NaYF 4 :Yb 3 + , Er 3 + when the reaction time increased from 5 to 24 h. When the solution was treated at 200 °C for 8–24 h at the pH value of 8–9, pure β -NaYF 4 :Yb 3 + , Er 3 + microspheres were obtained. The FE-SEM results showed that the morphology of pure α -NaYF 4 :Yb 3 + , Er 3 + was spherical nanoparticles with an average diameter of about 70 nm and the pure β -NaYF 4 :Yb 3 + , Er 3 + was microsphere with an average diameter of about 700 nm, which is composed of spherical nanoparticles (30 nm). The FT-IR and UV spectra showed that BSA had been conjugated with α -NaYF 4 :Yb 3 + , Er 3 + upconversion phosphors. The luminescence properties of α -( β -) NaYF 4 :Yb 3 + , Er 3 + phosphors were also studied. Under 980 nm excitation, the upconversion luminescence (UCL) intensity of β -NaYF 4 :Yb 3 + , Er 3 + microspheres was much stronger than that of α - NaYF 4 :Yb 3 + , Er 3 + nanoparticles. Moreover, both red and green upconversion were ascribed to the two-photon process.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2018
·
IF 3.972
Lihua He,Xiao Zou,Xiang He,Fengying Lei,Na Jiang,Qiaoji Zheng,Chenggang Xu,Yongfu Liu,Dunmin Lin
A variety of NaYF4:Yb/Er upconversion materials were successfully synthesized via a facile hydrothermal method by altering the volume ratios (0:1, 1:1, 2:1, 3:1, 4:1, 5:1) of ethanol to water and various alcohols (methanol, n-propyl alcohol, isopropyl alcohol, ethylene glycol, polyethylene glycol, and phemethylol), and the grain size and luminescence of the materials were effectively tailored. The addition of alcohol effectively reduces the grain size of the materials and simultaneously leads to the surprising enhancement of the UC emission. The increase in the volume ratio of EtOH/H2O causes the transformation of the crystal structure of the materials from hexagonal to cubic phase. The particle size of the material with the EtOH/H2O of 2:1 is almost 1000 times smaller than that of the material without EtOH, and the strongest luminescence is observed at the EtOH/H2O of 2:1. The type of alcohol in the solvent exhibits a significant influence on the luminescent properties of the materials. The NaYF4:Yb/Er nanocrystals obtained using different alcohols as solvent possess much a smaller grain size and stronger upconversion luminescence than that using water as solvent, and the NaYF4:Yb/Er materials with n-propyl alcohol exhibit the strongest luminescence intensity. The mechanism of the reduction of grain size and enhancement in the luminescence of the NaYF4:Yb3+, Er3+ upconversion materials has been proposed. This study may suggest a simple method to significantly reduce the grain size and improve the upconversion luminescence properties of NaYF4-based fluorescence material.
研究领域:
材料科学
·
光学
·
纳米技术
✓ 已验证
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2017
·
IF 2.446
Tie Cong,Yadan Ding,Xueqing Yu,Yue Mu,Xia Hong,Yichun Liu
A series of Cd 2+ doped hexagonal-phase NaYF 4 : Yb 3+ , Er 3+ upconversion nanoparticles (UCNPs) were synthesized via solvothermal method, and the effect of Cd 2+ on the upconversion luminescence (UCL) properties was investigated in detail. It was found that the introduction of Cd 2+ could enhance the UCL intensities of NaYF 4 : Yb 3+ , Er 3+ UCNPs significantly. The maximum enhancement occurred when the doping concentration of Cd 2+ was 7 mol%. Compared with the UCNPs without Cd 2+ doping, the total integral emission intensity was enhanced by ∼38 times. It was related to the unit cell expansion and the generated F − vacancies, which could decrease the crystal symmetry around the Er 3+ ions. The results shall facilitate the improvement of UCL properties and the potential applications of UCNPs in lighting, solar cells, optics encoding and so on.
研究领域:
材料科学
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纳米技术
·
光学
✓ 已验证
产品关联
DOI
高影响因子
EPL
·
2011
·Vol. 96
·期 1
·18001
·
IF 2.753
A. H. Li,Q. Lü
The knowledge of the power density for which luminescence intensity reversal begins with power increase is of valuable importance for practical applications. Under 980 nm CW diode laser excitation, the maximum upconversion luminescence intensities were obtained at 4800, 5700, and 7100 W/cm2 for 2H9/2→4I15/2, 2H11/2&4S3/2→4I15/2, and 4F9/2→4I15/2 transition luminescences, respectively, in compact powder composed by cubic-phase NaYF4:
Yb3+,Er3+ nanoparticles with a most probable diameter of ∼46 nm. It was revealed experimentally that the reversal power density decreases as luminescent level rises. Excitation increase combined with radiative quantum efficiency decrease as power increase can reproduce this "n"-shape power dependence relationship.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Wei Gao,Jinglei Zhang,Lin Shao,Jiaxi Li,Peng Ding,Qingyan Han,Xuewen Yan,Chenyun Zhang,Jun Dong
Enhancing upconversion luminescence in rare-earth materials through the plasmonic effects of precious metals has emerged as a highly effective strategy. In this study, we explore three distinct self-assembly techniques to fabricate alloy nano-film substrates using silver-coated gold (Au@Ag) core-shell nanoparticles, each with unique structural attributes. To enhance the upconversion luminescence of Er 3+ ions, we combine these substrates with NaYF 4 :Yb 3+ /Er 3+ nanoparticles, creating NaYF 4 :Yb 3+ /Er 3+ /Au@Ag composite nanostructures. The upconversion emission of Er 3+ ions is observably boosted when directly combined with Au@Ag nano-films of various structures under a 980 nm laser excitation. Surprisingly, incorporating a NaYF 4 inert shell as an isolating layer results in a remarkable 13.7-fold enhancement of upconversion luminescence in the NaYF 4 :Yb 3+ /Er 3+ @NaYF 4 /Au@Ag composite structure relative to isolated NaYF 4 : Yb 3+ /Er 3+ nanoparticles. The enhancement mechanism was carefully discussed based on spectral characteristics and luminous lifetime. It was found that the enhanced upconversion emission of nanoparticles on differently structured substrates is primarily driven by excitation enhancement. The composite rare-earth and metal nanoparticle structures fabricated in this investigation not only effectively enhance material spectral properties effectively but also streamline the process by employing an inert NaYF 4 shell as an isolation layer. This novel approach offers a promising avenue for developing efficient luminescent material systems.
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
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Xiaohong Li,Xiaozhen Zhang,Renhua Chen,Huafeng Liu,Leying Wang,Si Cheng,Yongzhi Yu
The internal modification with rare earth ion doping proved to be a very effective strategy for improving the luminescent properties of NaYF 4 -based upconversion materials. However, greatly enhancing the luminescence efficiency of NaYF 4 :Yb 3+ /Er 3+ remains a major challenge. Herein, the effects of Sn 4+ doping on the structure and luminescent performance of such material were explored. The hydrothermal molten-salt method was applied to synthesize the Sn 4+ -doped NaYF 4 :Yb 3+ /Er 3+ upconversion materials, and their crystal structures, morphologies, surface chemical composition and element states, and luminescence performance were characterized. It was found that Sn 4+ doping can significantly enhance the luminescence intensity and tailor the chromaticity of NaYF 4 :Yb 3+ /Er 3+ . In particular, the green (G) and red (R) luminescence intensity levels of the 30 mol% Sn 4+ doped material were increased by factors of 26.97 and 38.91, respectively. The R/G ratio was incremented from 0.34 for the undoped material to 0.83 for the 40 mol% Sn 4+ doped counterpart. The Sn 4+ doping led to the change of lattice distortion and crystal growth pattern of NaYF 4 :Yb 3+ /Er 3+ . The mechanism for Sn 4+ doping to affect the luminescence properties of the prepared upconversion material was also explored. The changes in luminescence intensity levels and R/G ratios could be attributed to the highly asymmetric distorted lattice and crystal field resulting from Sn 4+ doping.
研究领域:
材料科学
·
光学
✓ 已验证
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 Materials Chemistry C
·
2018
·Vol. 6
·期 38
·10360-10366
·
IF 5.976
Xiaokai Xu,Wei Li,Wan Zhou,Guiping Tan,Yihao Zheng,Chaofan Hu,Bingfu Lei,Xuejie Zhang,Yingliang Liu,Jianle Zhuang
Herein, NaYF4:Yb,Tm@SiO2/carbon dot nanocomposites have been successfully fabricated by a facile route. The structure and morphology of the nanocomposites were characterized by SEM, TEM, XRD, FT-IR and XPS measurements. It was demonstrated that carbon dots were embedded well in the silica layer coating on the surface of NaYF4:Yb,Tm nanoparticles, leading to a relatively stable structure of the nanocomposites. The nanocomposites showed interesting dual-mode luminescence properties, i.e. blue green light under a 365 nm UV lamp and blue purple light under a 980 nm laser. They were utilized to achieve light conversion films, ion detection probes and cell imaging, suggesting their great potential in the fields of anti-counterfeiting and bioapplications.
研究领域:
材料科学
·
生物医学工程
✓ 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）