RSC Advances
·
2015
·Vol. 5
·期 19
·14123-14128
·
IF 3.84
Yue Tian,Bining Tian,Cai'e Cui,Ping Huang,Lei Wang,Baojiu Chen
Yb3+/Er3+ codoped spherical Gd2O3 phosphors with different particle sizes were prepared via a urea-assisted homogeneous precipitation process by adjusting the molar ratio of rare earth ions and urea followed by annealing at high temperature. The phases, morphologies, and luminescence properties of the as-prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and upconversion luminescence (UCL) spectra, respectively. The spherical Gd2O3:Yb3+/Er3+ phosphors showed size-dependent upconversion luminescence properties under the excitation of 980 nm-laser. The temperature sensing behavior of spherical Gd2O3:Yb3+/Er3+ phosphors with different particle sizes was studied based on the change of emission intensities from two thermally coupled 2H11/2 and 4S3/2 levels. It is interesting to observe that the sensing sensitivity of the sample increases with decreasing particle size and a sensitivity of 84 × 10−4 K−1 was obtained for the sample with a particle size of 45 nm. Finally, Judd–Ofelt theory was used for explaining and predicting the effect of particle size on sensing sensitivity.
研究领域:
材料科学
·
无机化学
·
光学材料
·
生物医学工程
·
纳米技术
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 103
·101707-101713
·
IF 3.289
Shengjun Zhang,Jiajia Zhou,Ruozhen Wu,Lei Lei,Zhen Xiao,Junjie Zhang,Shiqing Xu
Lanthanide (Ln3+)-doped nanoparticles that produce strong red upconversion (UC) luminescence are desirable for biological applications. For nanoparticles, modification of their electronic properties and stabilization of their crystallographic phase are crucial for tuning their luminescence behaviors. Here, Yb3+–Er3+ doped Gd2O3 nanoparticles have been synthesized by calcining Gd2O2S in nitrogen (O2-free) and ambient air (∼21% O2), respectively. Various approaches including X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy and thermo-gravimetric and differential thermal analyses (TG-DTA) were used to characterize the structure, morphology and phase formation mechanism of the nanoparticles. Upconversion luminescence properties were investigated by emission intensity vs. excitation power (double logarithmic relationship) and temperature dependent emission spectroscopy. The different splitting transition probabilities of the cubic and/or monoclinic phase, the probability of multiphonon relaxations and cross relaxations between Er3+ ions are responsible for the efficient red emission in the cubic Gd2O3 nanoparticles. More importantly, the lower phonon energy of the pure cubic sample has good thermal stability in the current detectable range of 20–100 °C. These results imply that the cubic Gd2O3 upconversion nanoparticles may have multiplexing functionality in bio-imaging.
研究领域:
材料科学
·
生物医学工程
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2018
·
IF 2.732
Jun Liu,Huawei Deng,Fengzhen Lv,Wenjie Kong,Dihu Chen,Fuchi Liu,Lizhen Long
The large number of energy levels available to lanthanide ions makes the emission mechanism of lanthanide-doped luminescent materials extremely complicated. Herein, we focus on the discussion and analysis of luminescence manipulation in Gd 2 O 3 :Yb 3+ /Er 3+ nanocrystals and systematically investigate ion-ion interaction–induced energy transfer in up- and downconversion processes to shed light on the manipulation mechanism, showing that the luminescence of the above nanocrystals can be controlled by varying the content of Yb 3+ . Based on Dexter's energy transfer theory and the fact that excitation of Er 3+ ions results in the appearance of emission attributed to the 2 F 5/2 → 2 F 7/2 transition of Yb 3+ in the near-infrared region (950–1100 nm), this behavior is ascribed to the occurrence of energy transfer from Er 3+ to Yb 3+ .
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
BIOMATERIALS
·
2012
·
IF 7.404
Zhen Liu,Fang Pu,Sa Huang,Qinghai Yuan,Jinsong Ren,Xiaogang Qu
Due to their unique electric, magnetic, and optical properties, engineered nanostructures have been applied to provide diagnostic, therapeutic, as well as prognostic information about the status of disease. In this study, we report a multifunctional nanoprobe based on PEGylated Gd 2 O 3 :Yb 3+ , Er 3+ nanorods (denoted as PEG-UCNPs) for in vivo up-conversion luminescence (UCL), T 1 -enhanced magnetic resonance (MR), and X-ray computed tomography (CT) multi-modality imaging. A facile and large-scale hydrothermal system combining the merits of an in situ thermal decomposition method and a surface-modified approach is introduced to construct high-quality PEG-UCNPs. By grafting PEG molecules on the surface of PEG-UCNPs, the nanostructures possess excellent stability against in vivo environment and hold long blood circulation time. Cell-cytotoxicity assay, hemolyticity, as well as post-injection histology, hematology, and inflammation analysis further demonstrate their non-cytotoxic character and indicate further in vivo application. In detail, the capability of PEG-UCNPs as high-performance contrast agents for UCL/MR/CT imaging is evaluated successfully through small-animal experiments. Additionally, pharmacokinetics, biodistribution, and clearance route are studied after intravenous injection in a mouse model, reflecting their overall safety.
研究领域:
纳米技术
·
材料科学
·
生物医学工程
·
医学影像
·
分子诊断
✓ 已验证
DOI
PubMed
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2015
·Vol. 17
·期 23
·15412-15418
·
IF 4.493
Jun Liu,Huawei Deng,Zhanyun Huang,Yueli Zhang,Dihu Chen,Yuanzhi Shao
Manipulation of upconversion (UC) emission is of particular importance for multiplexed bioimaging. Here, we precisely manipulate the UC color output by utilizing the phonon-assisted energy back transfer (EBT) process in ultra-small (sub-10 nm) Gd2O3:Yb3+/Er3+ UC nanoparticles (UCNPs). We synthesized the Gd2O3:Yb3+/Er3+ UCNPs by adopting the laser ablation in liquid (LAL) technique. The synthesized Gd2O3:Yb3+/Er3+ UCNPs are small spherical and monoclinic structures. Continuous color-tunable (from green to red) UC fluorescence emission is achieved by increasing the concentration of Yb3+ ions from 0 to 15 mol%. A phonon-assisted energy back transfer (EBT) process from Er3+ (4S3/2 → 4I13/2) to nearby Yb3+ (2F7/2 → 2F5/2), which can significantly enhance red emission at 672 nm and decrease green emission, is responsible for the color-tunable UC emission by increasing the Yb3+ concentration in Gd2O3:Yb3+/Er3+ UC nanoparticles.
研究领域:
纳米医学
·
生物成像
·
光功能材料
·
分子影像学
·
转化医学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）