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1.
The Y2O3: Yb3 , Er3 microstructures were fabricated by a hydrothermal method without surfactants.The microstructures structure was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM,KYKY 1000B).The up-conversion luminescence spectra were studied under 978 nm laser diode excitation.In Yb3 and Er3 codoped Y2 O3 microcrystals, the relative intensity of green emission became stronger as the morphology of sample changed from wires to films. 相似文献
2.
以9-蒽甲酸(9-ACA)为发光剂,八乙基卟啉钯(Pd OEP)为光敏剂,在二者最佳配比〔n(9-ACA)∶n(Pd OEP)=80∶1〕下,构建了对溶液中氢离子和氢氧根离子具备灵敏响应性的上转换发光体系9-ACA/PdOEP。当pH处于4~8以及8~11时,上转换发光强度均与pH呈现良好的线性关系。参比实验中,单一组分9-ACA本身的荧光强度与pH没有呈现线性关系,证明了9-ACA/Pd OEP体系对于pH的宽范围响应来源于光敏剂与发光剂之间的三线态-三线态能量转移(TTET)过程。 相似文献
3.
Bioimaging: Shaping Luminescent Properties of Yb3+ and Ho3+ Co‐Doped Upconverting Core–Shell β‐NaYF4 Nanoparticles by Dopant Distribution and Spacing (Small 47/2017) 下载免费PDF全文
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5.
Phototherapy: Hierarchical Plasmonic Nanorods and Upconversion Core–Satellite Nanoassemblies for Multimodal Imaging‐Guided Combination Phototherapy (Adv. Mater. 5/2016) 下载免费PDF全文
6.
Ultrasmall near-monodisperse Ba2ErF7 nanocrystals with average crystal size 9.6 nm were synthesized with solvothermal method. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) assays reveal that the as-synthesized Ba2ErF7 nanocrystals are of the cubic structure with the cell parameter of 5.943 A, instead of the reported orthorhombic and tetragonal structure. Two emission bands originated from 2Hwj4H3/2 → 4F5/2 and 4F9/2 ----+ 4115,2 of Er3+ can be observed under a 980 nm laser excitation. The magnetic mass susceptibility of the as-synthesized BazErF7 nanocrystals reaches 4.293 × 10-5 emu g-1 Oe-1. 相似文献
7.
Tsung-Han Ho Chien-Hsin Yang Zheng-En Jiang Hung-Yin Lin Yih-Fung Chen Tzong-Liu Wang 《International journal of molecular sciences》2022,23(15)
To date, the increase in reactive oxygen species (ROS) production for effectual photodynamic therapy (PDT) treatment still remains challenging. In this study, a facile and effective approach is utilized to coat mesoporous silica (mSiO2) shell on the ligand-free upconversion nanoparticles (UCNPs) based on the LiYF4 host material. Two kinds of mesoporous silica-coated UCNPs (UCNP@mSiO2) that display green emission (doped with Ho3+) and red emission (doped with Er3+), respectively, were successfully synthesized and well characterized. Three photosensitizers (PSs), merocyanine 540 (MC 540), rose bengal (RB), and chlorin e6 (Ce6), with the function of absorption of green or red emission, were selected and loaded into the mSiO2 shell of both UCNP@mSiO2 nanomaterials. A comprehensive study for the three UCNP@mSiO2/PS donor/acceptor pairs was performed to investigate the efficacy of fluorescence resonance energy transfer (FRET), ROS generation, and in vitro PDT using a MCF-7 cell line. ROS generation detection showed that as compared to the oleate-capped and ligand-free UCNP/PS pairs, the UCNP@mSiO2/PS nanocarrier system demonstrated more pronounced ROS generation due to the UCNP@mSiO2 nanoparticles in close vicinity to PS molecules and a higher loading capacity of the photosensitizer. As a result, the three LiYF4 UCNP@mSiO2/PS nanoplatforms displayed more prominent therapeutic efficacies in PDT by using in vitro cytotoxicity tests. 相似文献
8.
《Measurement》2014
The effect of the localized surface plasmon resonance (SPR) on optical absorption and photoluminescence of Sm3+-doped sodium borosilicate glass containing reduced silver nanoparticles (NPs) is reported (Ag+ → Ag0). The interaction of ultraviolet light by metallic NPs and its effect on the optical properties of samarium in proposed glass were investigated by absorption and photoluminescence spectra analysis. The existence of the NPs was pursued by transmission electron microscopy technique, revealing the existence of Ag NPs with average size of ∼8–14 nm. The largest enhancement was achieved for emission at 561 nm. Such improvements were attributed and discussed by enhanced electric field around metallic NPs and energy transfer (ET) between Sm3+ ions and silver NPs. 相似文献
9.
《Ceramics International》2022,48(21):31344-31353
Highly thermally stable Er3+/Tm3+/Yb3+ tri-doped bismuth lanthanum tungstate phosphors were prepared by high temperature solid-state reaction method. The structural and morphological properties of the prepared phosphors were analysed by X-ray diffraction (XRD), Raman spectroscopy and Scanning electron microscopy (SEM) coupled with energy dispersion spectrum (EDS). Visible upconversion (UC) luminescence was measured by exciting the phosphors with 980 nm laser radiation. The dependence of the UC intensity of each emission band of Er3+ and Tm3+ ions as a function of temperature in the range from 30 to 300 K was monitored. Fluorescence intensity ratios (FIR) of thermally coupled levels (TCL) and non-thermally coupled levels (NTCL) were analysed and verified with appropriate theoretical validation. The absolute (SA) and relative sensitivities (SR) were estimated and compared with the reported systems. In the present case of BiLaWO6: Er3+/Tm3+/Yb3+, SR (0.43 % K?1) related to TCL of Er3+ UC is found to have maximum sensitivity compared to any of the NTCL combinations at 300 K. From this study we inferred that the SR values estimated from NTCL are smaller than that of TCL involved in BLW: Er3+/Tm3+/Yb3+ phosphor. The temperature dependent CIE color coordinates were also evaluated in the cryogenic temperature region. 相似文献
10.
Hongqiang Cui Yongze Cao Ying Li Lei Li Yuhang Zhang Guojian Li Yichao Wang Xiangping Li Baojiu Chen 《International Journal of Applied Ceramic Technology》2022,19(6):3358-3366
A series of Sr2.99-x(PO4)2:.01Er3+/xYb3+ (x = .02, .04, .06, .08, .10) phosphors in the presence of impurity Tm3+ were synthesized by high temperature solid-state method, and X-ray diffraction results show that these samples are pure R-3 m(166) space group phase. The upconversion luminescence (UCL) of Er3+ and impurity Tm3+ under 980-nm laser excitation were investigated, and the results show that the intense blue UCL of impurity Tm3+ and thermal enhancement of 2H11/2→4I15/2 of Er3+ simultaneously exist. When Er3+ doping concentration is kept at .01, both the blue UCL intensity of impurity Tm3+ and green and red UCL intensity of Er3+ reach the maximum at Yb3+ doping concentration of .08. The thermal enhancement effect of 2H11/2→4I15/2 of Er3+ was observed as high as 3.27 times from 303 to 723 K, which is because of lattice distortion and phonon-assisted transition. In addition, the optical temperature performance of Sr2.91(PO4)2:.01Er3+/.08Yb3+ sample was studied, and the maximum absolute temperature sensitivity was calculated as .00623 K−1 at 538 K. This study suggests that Sr3(PO4)2:Er3+/Yb3+ phosphors in the presence of impurity Tm3+ have a promising application prospect as optical temperature sensor at high temperature. 相似文献