JOURNAL OF POWER SOURCES
·
2019
·
IF 7.467
Qiyao Guo,Jihuai Wu,Yuqian Yang,Xuping Liu,Jinbiao Jia,Jia Dong,Zhang Lan,Jianming Lin,Miaoliang Huang,Yuelin Wei,Yunfang Huang
The introduction of upconversion materials as spectral converter into photovoltaic devices to harvest and convert near infrared photons to visible photons that can thus be absorbed by perovskite layer is a promising strategy for enhancing the performance of perovskite solar cells . Hence, β-NaYF 4 :Yb 3+ /Er 3+ /Sc 3+ @NaYF 4 rare-earth doped upconversion nanoparticles with core-shell structure are synthesized. The doped rare-earth ions Yb 3+ and Er 3+ convert near infrared light to red and green light, and the Sc 3+ ions enhance the upconversion luminescence efficiency, which broaden the absorption range of solar irradiation and generate extra photocurrent in the solar cells. The surface defects of β-NaYF 4 :Yb 3+ /Er 3+ /Sc 3+ is passivated by the even NaYF 4 shell, which results in the obvious enhancement in upconversion emission intensity. Consequently, the perovskite solar cell based on the rare-earth doped upconversion nanoparticle mesoporous layer achieves a high power conversion efficiency of 20.19%, while the device based on TiO 2 mesoporous layer gets an efficiency of 17.44%.
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高影响因子
NANOTECHNOLOGY
·
2018
·Vol. 29
·期 9
·094001
·
IF 3.404
Zengliang Shi,Yue Duan,Xingjun Zhu,Qiwei Wang,DongDong Li,Ke Hu,Wei Feng,Fuyou Li,Chunxiang Xu
Lanthanide-doped up-conversion nanoparticles (UCNPs) provide a remote temperature sensing approach to monitoring biological microenvironments. In this research, the UCNPs of NaYF4:Yb3+, Er3+@NaYF4:Yb3+, Nd3+ with hexagonal (β)-phase were synthesized and applied in cell temperature sensing as well as imaging after surface modification with meso-2, 3-dimercaptosuccinic acid. In the core–shell UCNPs, Yb3+ ions were introduced as energy transfer media between sensitizers of Nd3+ and activators of Er3+ to improve Er3+emission and prevent their quenching behavior due to multiple energy levels of Nd3+. Under the excitations of 808 nm and 980 nm lasers, the NaYF4:Yb3+, Er3+@NaYF4:Yb3+, Nd3+ nanoparticles exhibited an efficient green band with two emission peaks at 525 nm and 545 nm, respectively, which originated from the transitions of 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 for Er3+ ions. We demonstrate that an occurrence of good logarithmic linearity exists between the intensity ratio of these two emission peaks and the reciprocal of the inside or outside temperature of NIH-3T3 cells. A better thermal stability is proved through temperature-dependent spectra with a heating–cooling cycle. The obtained viability of NIH-3T3 cells is greater than 90% after incubations of about 12 and 24 (h), and they possess a lower cytotoxicity of UCNPs. This work provides a method for monitoring the cell temperature and its living state from multiple dimensions including temperature response, cell images and visual up-conversion fluorescent color.
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PubMed
高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2018
·Vol. 18
·期 12
·8258-8268
·
IF 1.354
Tong Chao,Xie Shaowen,Zhou Hu,Li Na,Gong Liang,Jian Jian,Zhang Changfan,Xu Lijian,Xu Jianxiong
In this study, well-defined PAA-coated NaYF4:Yb3+, Er3+ nanophosphors were synthesized via a poly(acrylic acid) (PAA) mediated hydrothermal process. The rational control of initial reaction conditions, such as hydrothermal temperature, pH value of precursor-solution,
added amount of PAA, and molecular weight of PAA ligand, resulted in upconversion of NaYF4:Yb3+, Er3+ phosphors with varying crystal phases (α and β) and morphologies (e.g., nanosphere, submicrorod, microrod, microtube, and microprism).
By assessing the upconversion luminescent properties of the synthesized NaYF4:Yb3+, Er3+ phosphors upon excitation by 980 nm infrared light, it was demonstrated that the β-phase NaYF4:Yb3+, Er3+ phosphors generally
presented stronger upconversion luminescent than α-phase NaYF4:Yb3+, Er3+ phosphors and orthorhombic phase of YF3:Yb3+, Er3+ sample. Additionally, the β-phase NaYF4:Yb3+, Er3+
phosphors with hollow microtube morphology presented higher upconversion luminescent intensity than phosphors of other morphologies. This may be due to microtubes having larger surface area (inner and outer surfaces), which promoted the absorption efficiency under similar excitation conditions,
therefore generating higher luminescent intensity. Findings form this study suggest for precisely controlled growth of other complex rare earth fluoride compounds and provide a reference for exploration of component-, phase- and morphology-dependent upconversion luminescence properties.
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DOI
PubMed
高影响因子
MATERIALS RESEARCH BULLETIN
·
2018
·
IF 2.873
Song Ye,Ping Xiao,Huazhen Liao,Song Li,Deping Wang
We developed a facile approach for the fast synthesis of ultrasmall and monodisperse β-NaYF 4 :Yb 3+ , Er 3+ nanocrystals down to 5.3 nm with the assistant of oleate ligands, based on which the highly bright sub-10 nm β-NaYF 4 :Yb 3+ , Er 3+ @NaYF 4 core-shell nanocrystals with three order of magnitude increased upconversion emission were successfully obtained by a seed-mediated growth method. The reaction time and temperature dependent experimental results implied that the introduciton of extra oleate ligands can both promote the α-to-β phase transition and impeded the crystal growth of NaYF 4 , which is due to the oleate ligand induced orderly arrangement of Y 3+ and capping effect, respectively. It is expected that the oleate ligands mediated phase transition and size evaluation, demonstrated here in NaYF 4 :Yb 3+ , Er 3+ NCs, is also applicable to other lanthanide-doped upconversion nanocrystals.
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高影响因子
JOURNAL OF LUMINESCENCE
·
2020
·
IF 3.28
Hao Tang,Hua Zhou,Xianhua Cheng
The green and red upconversion (UC) emissions of 35 mol% Ca 2+ doped β-NaYF 4 :Yb 3+ /Er 3+ microcrystals were improved to 102.8 and 43.1 times higher than those of Ca 2+ -free counterparts. X-ray powder diffraction spectra, scanning electron microscopy, Fourier transform infrared spectroscopy , upconversion luminescence (UCL) spectroscopy and Judd-Ofelt analysis were performed to investigate the mechanism of UCL intensity enhancement caused by Ca 2+ doping. The hexagonal-to-cubic phase transition was observed when Ca 2+ doping concentration exceeded 35 mol%. The incorporation of Ca 2+ into hexagonal microcrystals lattice induced unit cell volume enhancement and microcrystals surface to volume ratio variation, which affected the UCL intensity by hindering the non-radiative energy loss process via Yb 3+ /Er 3+ ions and changing the amount of surface quenchers adsorbed on the microcrystals surface. The hypersensitive transition related local crystal field asymmetry around Er 3+ in the grown hexagonal microcrystals was also investigated by Judd-Ofelt analysis but unexpectedly found to be the less dominant factor for the UCL intensity variation. This study helps to realize the mechanism of impurity ion doping resulted UCL intensity enhancement, which is instructive for high-performance UC microcrystals synthesis.
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高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2017
·Vol. 100
·期 7
·3061-3069
·
IF 2.841
Shaohua Fan,Shikai Wang,Hongtao Sun,Shiyu Sun,Guojun Gao,Lili Hu
We report efficient dual-mode up-conversion (UC) and down-shifting (DS) emission in a single Yb 3+ /Er 3+ -co-doped β-NaYF 4 microcrystals with controlled morphology and size via a simple Na + ion-exchange modification (IEM) method. IEM well preserves the crystal structure and monodispersed morphology of hydrothermal-synthesized β-NaYF 4 . Meanwhile, IEM gives rise to the significant enhancement of UC emission intensity up to 3800 times and strongly enhanced DS emission intensity of Er 3+ and Yb 3+ by several times in β-NaYF 4 :Yb 3+ ,Er 3+ microcrystals. IEM also strongly prolongs the DS emission lifetimes of Er 3+ and Yb 3+ in visible and near-infrared region. The enhanced UC and DS emission intensities and prolonged lifetimes in β-NaYF 4 :Yb 3+ ,Er 3+ are mainly ascribed to the dispersing of localized Yb 3+ and Er 3+ clusters during IEM.
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高影响因子
Nanoscale
·
2017
·Vol. 9
·期 22
·7666-7673
·
IF 7.367
Xin Su,Xiaoqian Sun,Suli Wu,Shufen Zhang
Photonic crystals (PCs) have long been considered effective for tuning upconversion luminescence due to their photonic band gap (PBG) and the redistribution of density of optical states (DOS). Although the emission intensity can be changed obviously by the PC effect, rarely an obvious lifetime change consistent with theory is observed due to the low refractive index of PS or SiO2 spheres in the commonly used PCs. Herein, CdS/NaYF4:Yb3+,Er3+ composite PCs with a high refractive index contrast are fabricated in one step with upconversion nanoparticles filled inside CdS PCs. When the upconversion emission peak lies at the edge of the PBGs of the composite PCs, a dramatic decrease in lifetime by 28% and 41% is observed for the green and red emissions, respectively. At the same time, obvious emission intensity enhancements are also observed. In contrast, PS PCs with a low refractive index contrast show a slight effect on the lifetime of upconversion luminescence with their emission peak at the edge of the PBGs. Our results agree well with theory and prove that a sufficiently large refractive index contrast is necessary for PCs to dramatically tune the luminescence lifetime and intensity simultaneously.
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PubMed
高影响因子
OPTICAL MATERIALS
·
2024
·
IF 3.8
Jinfeng Wang,Rui Jiang,Shuo Zhou,Bin Feng,PanPan Mou,Hongze Yang,Yanmei Zhang,Xianbo Zhang,Guosong Chen,Ying Hong
Using nitrilotriacetic acid (NTA) as the capping agent, β -NaYF 4 upconversion microcrystals (UCMCs) were successfully synthesized via a hydrothermal synthesis method. Systematic investigations were conducted to evaluate the influence of NTA/Ln molar ratio, NaF/Ln molar ratio, and pH on the morphology, size, and crystal phase characteristics of the UCMCs. Multiple characterization techniques, such as scanning electron microscope (SEM) and X-ray diffractometer (XRD), were employed to elucidate these effects. The experimental findings reveal that these parameters exert a substantial influence on the morphology and size of the UCMCs, with the crystal phase alterations primarily governed by variations in the NaF/Ln molar ratio. Furthermore, a comprehensive exploration of the growth mechanism of UCMCs was undertaken based on the modulation of reaction time. The emission spectra of the synthesized UCMCs were meticulously investigated, unveiling that microcrystals exhibiting larger size and enhanced crystallinity display more pronounced luminescent properties. Comparative analysis with UCMCs synthesized using ethylenediaminetetraacetic acid (EDTA) and sodium citrate (Na 3 Cit) as capping agents, which are extensively applied in diverse fields, demonstrated the superior luminescence properties of the newly obtained NTA-UCMCs. In addition, NTA-UCMCs were also employed for the fabrication of transparent and flexible fluorescent films. This research thus presents a novel approach for the synthesis of highly luminescent UCMCs, holding promise for various applications in practical contexts.
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高影响因子
Journal of Physical Chemistry C
·
2011
·
IF 4.524
Xiaojiao Kang,Ziyong Cheng,Chunxia Li,Dongmei Yang,Mengmeng Shang,Ping’an Ma,Guogang Li,Nian Liu,Jun Lin
Core–shell structured up-conversion luminescent and mesoporous NaYF4:Yb3+/Er3+@nSiO2@mSiO2 nanospheres were prepared by coating mesoporous SiO2 layers with different thicknesses on NaYF4:Yb3+/Er3+ nanoparticles via a simple two-step sol–gel process. The obtained sample shows a typical mesoporous structure and well-dispersed spherical morphology with a narrow size distribution. The nanospheres exhibit little cytotoxicity (via MTT assay), and ibuprofen (IBU) was used as a model drug to access the release properties of the system in detail. The amount of IBU adsorbed in mesoporous channels increases with the thickness of the ordered mesoporous silica shell coated on the NaYF4:Yb3+/Er3+ nanoparticles. The in vitro release study of IBU reveals a release profile in two steps: an initial diffusion-controlled release, followed by a slower release rate. Furthermore, upon excitation by a 980 nm near-infrared laser, the nanospheres emit green (2H11/2 and 4S3/2 → 4I15/2) and red (4F9/2 → 4I15/2) fluorescence of Er3+ even after the loading of IBU. Interestingly, the emission intensity of Er3+ in the bifunctional (mesoporous and luminescence) drug carrier increases with an increase of the cumulative released amount of the model drug (IBU). Thus, the extent of drug release can be easily identified, tracked, and monitored based on the change of the up-conversion luminescence. These results suggest that the core–shell structured NaYF4:Yb3+/Er3+@nSiO2@mSiO2 nanospheres are a promising material for controlled drug release.
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高影响因子
JOURNAL OF RARE EARTHS
·
2017
·
IF 2.429
Song LI,Song YE,Xiao CHEN,Tianhua LIU,Zhuang GUO,Deping WANG
Yb 3+ and Er 3+ ions co-doped NaYF 4 nanocrystals were synthesized with different amounts of NaOH via oleic acid (OA)-assisted hydrothermal process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and photoluminescence spectra were used to characterize the products. The result indicated that the introduction of NaOH into the initial reaction solution effectively promoted the cubic (α-) to hexagonal (β-) phase transition of NaYF 4 :Yb 3+ ,Er 3+ nanocrystals, while excessive amount of NaOH favored the formation of α-NaYF 4 :Yb 3+ ,Er 3+ nanocrystals. Besides, with the increase of NaOH amount, the morphologies of β-NaYF 4 :Yb 3+ ,Er 3+ nanocrystals varied from irregular nanobranch to uniform nanorod. Further investigation revealed that the addition of NaOH could facilitate the deprotonation of OA, leading to the formation of oleate (OA − ), and meanwhile increased the concentration of OH − ions, inducing consequently the phase transition and morphology evolution of NaYF 4 :Yb 3+ ,Er 3+ nanocrystals. Moreover, the upconversion luminescence properties of NaYF 4 :Yb 3+ ,Er 3+ nanocrystals were systematically investigated. It was found that the upconversion emissions not only depended on the phase and morphology but also were influenced by the surface groups.
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高影响因子
Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 20
·5453-5461
·
IF 5.976
Shaohua Fan,Guojun Gao,Shiyu Sun,Sijun Fan,Hongtao Sun,Lili Hu
Absolute quantum efficiency (QE) of up-conversion (UC) materials is still limited to ∼3%, which strongly limits their applications in many areas. Herein, we report highly efficient UC β-NaYF4:Yb3+,Er3+ micro-cylinders prepared via a newly developed Li+/Na+ ion exchange method (IEM) with absolute QE as high as ∼4.0%. A small amount of Li+ is interstitially incorporated in β-NaYF4:Yb3+,Er3+, which not only maintains well the micro-cylindrical morphology but also enhances the emission intensity by ∼40%, doubles absolute UCQE (∼3.0% under a fixed excitation power density of 15 W cm−2), and prolongs the lifetime. The UC excitation profile is composed of a sharp peak at 976 nm and a weak shoulder at 935 nm. The absolute UCQE of Li+/Na+ IEM β-NaYF4:Yb3+,Er3+ is systemically studied over a wide excitation power density of 0.4–100 W cm−2, and we obtained impressively high UCQE of 4.0% under 60 W cm−2 power density, which is among the highest values in the literature. The application of two green UC emissions of Li+/Na+ IEM β-NaYF4:Yb3+,Er3+ in ratiometric thermometers is successfully demonstrated. The high relative temperature sensitivity (SR) of 1113/T2 and excellent repeatability as indicated by three heating–cooling cycles (293–753 K) suggest their promising application as a temperature sensor.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2024
·
IF 2.7
Yuangong Ma,Wensheng Zhang,Zhifang Wu,Zhishan Liang,Youlin Huang,Qingmei Tan,Tianren Liu,Dongxue Han,Li Niu
In the realm of photocatalysis, effectively utilizing solar energy, especially the near-infrared (NIR) spectrum, presents substantial challenges. To tackle this issue, a novel composite of NaYF4:Yb3+/Er3+@Cu2O@MoS2@Fe3O4 (denoted as NYE@Cu2O@MoS2@Fe3O4) was ingeniously fabricated and assessed for the photodegradation of organic contaminants. By harnessing the distinct properties of upconversion materials, narrow bandgap semiconductors, and magnetic substances, the NYE@Cu2O@MoS2@Fe3O4 catalyst possesses a photodegradation rate of 92% for the rhodamine B dye under NIR light radiation, which is superior to NYE@Cu2O (50%) and NYE@Cu2O@MoS2 (85%). The enhanced performance in the near-infrared photocatalysis of NYE@Cu2O@MoS2@Fe3O4 is mainly attributed to the synergistic effect of various components, which promotes an increase in photo-induced carrier generation and facilitates their efficient transfer and energy utilization under NIR irradiation. This study provides a possible route for the near-infrared photocatalytic degradation of pollutants in areas with limited light or even dark conditions.
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高影响因子
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