14 results on '"Xiao, Jia‐Wen"'
Search Results
2. All‐Inorganic Manganese‐Based CsMnCl3 Nanocrystals for X‐Ray Imaging.
- Author
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Guan, Lin‐Quan, Shi, Shuo, Niu, Xiao‐Wei, Guo, Shi‐Chen, Zhao, Jian, Ji, Tian‐Meng, Dong, Hao, Jia, Feng‐Yan, Xiao, Jia‐Wen, Sun, Ling‐Dong, and Yan, Chun‐Hua
- Subjects
NANOCRYSTALS ,LIGHT emitting diodes ,OPTICAL properties ,X-ray absorption ,SOLAR cells ,RADIOLUMINESCENCE ,X-ray imaging - Abstract
Lead‐based halide perovskite nanomaterials with excellent optical properties have aroused great attention in the fields of solar cells, light‐emitting diodes, lasing, X‐ray imaging, etc. However, the toxicity of lead prompts researchers to develop alternatives to cut down the usage of lead. Herein, all‐inorganic manganese‐based perovskite derivatives, CsMnCl3 nanocrystals (NCs), with uniform size and morphology have been synthesized successfully via a modified hot‐injection method. These NCs have a direct bandgap of 4.08 eV and a broadband emission centered at 660 nm. Through introducing modicum lead (1%) into the CsMnCl3 NCs, the photoluminescence intensity greatly improves, and the quantum yield (PLQY) increases from 0.7% to 21%. Furthermore, the CsMnCl3:1%Pb NCs feature high‐efficiency of X‐ray absorption and radioluminescence, which make these NCs promising candidates for X‐ray imaging. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
3. Stabilizing RbPbBr3 Perovskite Nanocrystals through Cs+ Substitution.
- Author
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Xiao, Jia‐Wen, Liang, Yuan, Zhang, Siyu, Zhao, Yizhou, Li, Yujing, and Chen, Qi
- Subjects
- *
NANOCRYSTALS , *PEROVSKITE , *METHYLAMMONIUM , *X-ray diffraction , *RUBIDIUM - Abstract
ABX3‐type halide perovskite nanocrystals (NCs) have been a hot topic recently due to their fascinating optoelectronic properties. It has been demonstrated that A‐site ions have an impact on their photophysical and chemical properties, such as the optical band gap and chemical stability. The pursuit of halide perovskite materials with diverse A‐site species would deepen the understanding of the structure–property relationship of the perovskite family. In this work we have attempted to synthesize rubidium‐based perovskite NCs. We have discovered that the partial substitution of Rb+ by Cs+ help to stabilize the orthorhombic RbPbBr3 NCs at low temperature, which otherwise can only be obtained at high temperature. The inclusion of Cs+ into the RbPbBr3 lattice results in highly photoluminescent Rb1−xCsxPbBr3 NCs. With increasing amounts of Cs+, the band gaps of the Rb1−xCsxPbBr3 NCs decrease, leading to a redshift of the photoluminescence peak. Also, the Rb1−xCsxPbBr3 NCs (x=0.4) show good stability under ambient conditions. This work demonstrates the high structural flexibility and tunability of halide perovskite materials through an A‐site cation substitution strategy and sheds light on the optimization of perovskite materials for application in high‐performance optoelectronic devices. Adding stability: Lead halide perovskite nanocrystals (NCs) attract tremendous attention due to their extraordinary optical properties. Herein, we show that the partial substitution of Rb+ by Cs+ helps to stabilize the orthorhombic RbPbBr3 NCs at low temperature, which otherwise could only be obtained at high temperature (above 300 °C, see figure). [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
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4. The Emergence of the Mixed Perovskites and Their Applications as Solar Cells.
- Author
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Xiao, Jia‐Wen, Liu, Lang, Zhang, Deliang, De Marco, Nicholas, Lee, Jin‐Wook, Lin, Oliver, Chen, Qi, and Yang, Yang
- Subjects
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PEROVSKITE , *SOLAR cells , *PHOTOVOLTAIC cells , *LIGHT absorption , *ENERGY conversion - Abstract
The halide perovskite (PVSK) materials (with ABX3 formulation) have emerged as 'dream materials' for photovoltaic (PV) applications due to their remarkable physical properties such as high optical absorption coefficient, carrier mobility, long carrier diffusion lengths, etc. These properties have enabled the PV devices to reach higher than 20% power conversion efficiencies (PCE) in record time. The further pursuit of higher PCE and improved stability brings forth increasing interests in so-called 'mixed composition' PVSK materials, consisting of partial substitution of the A, B, and/or X-sites with alternative elements/molecules of similar size. Herein, we highlight the recent advances in developing mixed PVSK for PVs and their relevant optoelectronic properties. We mainly focus on mixed PVSK materials in the form of polycrystalline thin films, but also discuss nanostructured and two-dimensional (2D) PVSK materials due to the increasing interest of broad readership. Efforts are exerted to elucidate the design principles of mixed PVSK and fabrication techniques for high performance optoelectronic devices, which help deepen our fundamental understanding of mixed PVSK systems. We hope this review will shed light onto the design and synthesis of mixed PVSK materials to further the progress of PVSK photovoltaics towards higher efficiencies and longer lifetimes. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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5. Photon upconversion in Yb3+–Tb3+ and Yb3+–Eu3+ activated core/shell nanoparticles with dual-band excitation.
- Author
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Dong, Hao, Sun, Ling-Dong, Wang, Ye-Fu, Xiao, Jia-Wen, Yan, Chun-Hua, Tu, Datao, and Chen, Xueyuan
- Abstract
Exploring novel lanthanide-activated upconversion nanoparticles with distinctive spectral fingerprints and emission lifetimes has long been a great concern for extended optical applications. Herein, we report the study of photon upconversion emissions in Yb
3+ –Tb3+ and Yb3+ –Eu3+ activated nanoparticles with near-infrared excitation. In these nanoparticles, a high content of Yb3+ is required for the simultaneous excitation of two Yb3+ ions, yielding a Yb3+ dimer with a higher excited energy to upconvert photons onto Tb3+ and Eu3+ . The optimum doping concentration of Yb3+ ions for Yb3+ –Tb3+ and Yb3+ –Eu3+ pairs was determined to be 80% and 60%, respectively, which are much higher than that of Yb3+ –Er3+ /Tm3+ pairs. Notably, the upconversion emission lifetime of the as-prepared nanoparticles was prolonged to 2.3 ms (Tb3+ ) and 4.0 ms (Eu3+ ), respectively. Through the epitaxial growth of a Nd3+ doped shell layer, the upconversion emissions of Tb3+ and Eu3+ were intensified 25-fold. At the same time, an extra excitation band in the shorter near-infrared region from Nd3+ at 808 nm was achieved. Moreover, the emissions of Tm3+ were employed to compensate for those of Tb3+ and Eu3+ for multicolor emissions. These results highlight the upconversion emissions of Tb3+ and Eu3+ for potential multicolor imaging and multiplexed detection applications. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
6. Rare-Earth Nanoparticles with Enhanced Upconversion Emission and Suppressed Rare-Earth-Ion Leakage.
- Author
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Wang, Ye-Fu, Sun, Ling-Dong, Xiao, Jia-Wen, Feng, Wei, Zhou, Jia-Cai, Shen, Jie, and Yan, Chun-Hua
- Published
- 2012
- Full Text
- View/download PDF
7. Inside Cover: Rare-Earth Nanoparticles with Enhanced Upconversion Emission and Suppressed Rare-Earth-Ion Leakage (Chem. Eur. J. 18/2012).
- Author
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Wang, Ye-Fu, Sun, Ling-Dong, Xiao, Jia-Wen, Feng, Wei, Zhou, Jia-Cai, Shen, Jie, and Yan, Chun-Hua
- Published
- 2012
- Full Text
- View/download PDF
8. All-Inorganic Manganese-Based CsMnCl 3 Nanocrystals for X-Ray Imaging.
- Author
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Guan LQ, Shi S, Niu XW, Guo SC, Zhao J, Ji TM, Dong H, Jia FY, Xiao JW, Sun LD, and Yan CH
- Subjects
- X-Rays, Manganese, Nanoparticles
- Abstract
Lead-based halide perovskite nanomaterials with excellent optical properties have aroused great attention in the fields of solar cells, light-emitting diodes, lasing, X-ray imaging, etc. However, the toxicity of lead prompts researchers to develop alternatives to cut down the usage of lead. Herein, all-inorganic manganese-based perovskite derivatives, CsMnCl
3 nanocrystals (NCs), with uniform size and morphology have been synthesized successfully via a modified hot-injection method. These NCs have a direct bandgap of 4.08 eV and a broadband emission centered at 660 nm. Through introducing modicum lead (1%) into the CsMnCl3 NCs, the photoluminescence intensity greatly improves, and the quantum yield (PLQY) increases from 0.7% to 21%. Furthermore, the CsMnCl3 :1%Pb NCs feature high-efficiency of X-ray absorption and radioluminescence, which make these NCs promising candidates for X-ray imaging., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)- Published
- 2022
- Full Text
- View/download PDF
9. Efficient Tailoring of Upconversion Selectivity by Engineering Local Structure of Lanthanides in Na(x)REF(3+x) Nanocrystals.
- Author
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Dong H, Sun LD, Wang YF, Ke J, Si R, Xiao JW, Lyu GM, Shi S, and Yan CH
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- Animals, Chickens, Fluorides pharmacokinetics, Lanthanoid Series Elements pharmacokinetics, Mice, Mice, Inbred Strains, Mice, Nude, Molecular Structure, Sodium pharmacokinetics, Tissue Distribution, Fluorides chemistry, Lanthanoid Series Elements chemistry, Nanoparticles chemistry, Sodium chemistry
- Abstract
Efficient tailoring of upconversion emissions in lanthanide-doped nanocrystals is of great significance for extended optical applications. Here, we present a facile and highly effective method to tailor the upconversion selectivity by engineering the local structure of lanthanides in Na(x)REF(3+x) nanocrystals. The local structure engineering was achieved through precisely tuning the composition of nanocrystals, with different [Na]/[RE] ([F]/[RE]) ratio. It was found that the lattice parameter as well as the coordination number and local symmetry of lanthanides changed with the composition. A significant difference in the red to green emission ratio, which varied from 1.9 to 71 and 1.6 to 116, was observed for Na(x)YF(3+x):Yb,Er and Na(x)GdF(3+x):Yb,Er nanocrystals, respectively. Moreover, the local structure-dependent upconversion selectivity has been verified for Na(x)YF(3+x):Yb,Tm nanocrystals. In addition, the local structure induced upconversion emission from Er(3+) enhanced 9 times, and the CaF2 shell grown epitaxially over the nanocrystals further promoted the red emission by 450 times, which makes it superior as biomarkers for in vivo bioimaging. These exciting findings in the local structure-dependent upconversion selectivity not only offer a general approach to tailoring lanthanide related upconversion emissions but also benefit multicolor displays and imaging.
- Published
- 2015
- Full Text
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10. Porous Pd nanoparticles with high photothermal conversion efficiency for efficient ablation of cancer cells.
- Author
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Xiao JW, Fan SX, Wang F, Sun LD, Zheng XY, and Yan CH
- Subjects
- Cell Death drug effects, HeLa Cells, Humans, Neoplasms metabolism, Neoplasms pathology, Hot Temperature, Metal Nanoparticles chemistry, Neoplasms therapy, Palladium chemistry, Palladium pharmacology, Phototherapy methods
- Abstract
Nanoparticle (NP) mediated photothermal effect shows great potential as a noninvasive method for cancer therapy treatment, but the development of photothermal agents with high photothermal conversion efficiency, small size and good biocompatibility is still a big challenge. Herein, we report Pd NPs with a porous structure exhibiting enhanced near infrared (NIR) absorption as compared to Pd nanocubes with a similar size (almost two-fold enhancement with a molar extinction coefficient of 6.3 × 10(7) M(-1) cm(-1)), and the porous Pd NPs display monotonically rising absorbance from NIR to UV-Vis region. When dispersed in water and illuminated with an 808 nm laser, the porous Pd NPs give a photothermal conversion efficiency as high as 93.4%, which is comparable to the efficiency of Au nanorods we synthesized (98.6%). As the porous Pd NPs show broadband NIR absorption (650-1200 nm), this allows us to choose multiple laser wavelengths for photothermal therapy. In vitro photothermal heating of HeLa cells in the presence of porous Pd NPs leads to 100% cell death under 808 nm laser irradiation (8 W cm(-2), 4 min). For photothermal heating using 730 nm laser, 70% of HeLa cells were killed after 4 min irradiation at a relative low power density of 6 W cm(-2). These results demonstrated that the porous Pd nanostructure is an attractive photothermal agent for cancer therapy.
- Published
- 2014
- Full Text
- View/download PDF
11. Dopant-induced modification of active site structure and surface bonding mode for high-performance nanocatalysts: CO oxidation on capping-free (110)-oriented CeO2:Ln (Ln = La-Lu) nanowires.
- Author
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Ke J, Xiao JW, Zhu W, Liu H, Si R, Zhang YW, and Yan CH
- Abstract
Active center engineering at atomic level is a grand challenge for catalyst design and optimization in many industrial catalytic processes. Exploring new strategies to delicately tailor the structures of active centers and bonding modes of surface reactive intermediates for nanocatalysts is crucial to high-efficiency nanocatalysis that bridges heterogeneous and homogeneous catalysis. Here we demonstrate a robust approach to tune the CO oxidation activity over CeO2 nanowires (NWs) through the modulation of the local structure and surface state around Ln(Ce)' defect centers by doping other lanthanides (Ln), based on the continuous variation of the ionic radius of lanthanide dopants caused by the lanthanide contraction. Homogeneously doped (110)-oriented CeO2:Ln NWs with no residual capping agents were synthesized by controlling the redox chemistry of Ce(III)/Ce(IV) in a mild hydrothermal process. The CO oxidation reactivity over CeO2:Ln NWs was dependent on the Ln dopants, and the reactivity reached the maximum in turnover rates over Nd-doped samples. On the basis of the results obtained from combined experimentations and density functional theory simulations, the decisive factors of the modulation effect along the lanthanide dopant series were deduced as surface oxygen release capability and the bonding configuration of the surface adsorbed species (i.e., carbonates and bicarbonates) formed during catalytic process, which resulted in the existence of an optimal doping effect from the lanthanide with moderate ionic radius.
- Published
- 2013
- Full Text
- View/download PDF
12. Nd(3+)-sensitized upconversion nanophosphors: efficient in vivo bioimaging probes with minimized heating effect.
- Author
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Wang YF, Liu GY, Sun LD, Xiao JW, Zhou JC, and Yan CH
- Subjects
- Absorption, Animals, Contrast Media chemistry, Heating, Hot Temperature, Infrared Rays, Lasers, Luminescence, Mice, Mice, Inbred BALB C, Mice, Nude, Particle Size, Photochemistry, Spectroscopy, Near-Infrared, Water chemistry, Diagnostic Imaging methods, Nanostructures chemistry, Neodymium chemistry, Phosphorus chemistry
- Abstract
Upconversion (UC) process in lanthanide-doped nanomaterials has attracted great research interest for its extensive biological applications in vitro and in vivo, benefiting from the high tissue penetration depth of near-infrared excitation light and low autofluorescence background. However, the 980 nm laser, typically used to trigger the Yb(3+)-sensitized UC process, is strongly absorbed by water in biological structures and could cause severe overheating effect. In this article, we report the extension of the UC excitation spectrum to shorter wavelengths, where water has lower absorption. This is realized by further introducing Nd(3+) as the sensitizer and by building a core/shell structure to ensure successive Nd(3+) → Yb(3+) → activator energy transfer. The efficacy of this Nd(3+)-sensitized UC process is demonstrated in in vivo imaging, and the results confirmed that the laser-induced local overheating effect is greatly minimized.
- Published
- 2013
- Full Text
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13. Triple-functional core-shell structured upconversion luminescent nanoparticles covalently grafted with photosensitizer for luminescent, magnetic resonance imaging and photodynamic therapy in vitro.
- Author
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Qiao XF, Zhou JC, Xiao JW, Wang YF, Sun LD, and Yan CH
- Subjects
- Apoptosis drug effects, Contrast Media chemistry, Contrast Media toxicity, Gadolinium DTPA chemistry, Gadolinium DTPA toxicity, HeLa Cells, Humans, Indoles chemistry, Magnetic Resonance Imaging, Organosilicon Compounds chemistry, Oxidation-Reduction, Photochemotherapy, Photosensitizing Agents toxicity, Singlet Oxygen metabolism, Spectroscopy, Near-Infrared, Fluorescent Dyes chemistry, Nanoparticles chemistry, Photosensitizing Agents chemistry
- Abstract
Upconversion luminescent nanoparticles (UCNPs) have been widely used in many biochemical fields, due to their characteristic large anti-Stokes shifts, narrow emission bands, deep tissue penetration and minimal background interference. UCNPs-derived multifunctional materials that integrate the merits of UCNPs and other functional entities have also attracted extensive attention. Here in this paper we present a core-shell structured nanomaterial, namely, NaGdF(4):Yb,Er@CaF(2)@SiO(2)-PS, which is multifunctional in the fields of photodynamic therapy (PDT), magnetic resonance imaging (MRI) and fluorescence/luminescence imaging. The NaGdF(4):Yb,Er@CaF(2) nanophosphors (10 nm in diameter) were prepared via sequential thermolysis, and mesoporous silica was coated as shell layer, in which photosensitizer (PS, hematoporphyrin and silicon phthalocyanine dihydroxide) was covalently grafted. The silica shell improved the dispersibility of hydrophobic PS molecules in aqueous environments, and the covalent linkage stably anchored the PS molecules in the silica shell. Under excitation at 980 nm, the as-fabricated nanomaterial gave luminescence bands at 550 nm and 660 nm. One luminescent peak could be used for fluorescence imaging and the other was suitable for the absorption of PS to generate singlet oxygen for killing cancer cells. The PDT performance was investigated using a singlet oxygen indicator, and was investigated in vitro in HeLa cells using a fluorescent probe. Meanwhile, the nanomaterial displayed low dark cytotoxicity and near-infrared (NIR) image in HeLa cells. Further, benefiting from the paramagnetic Gd(3+) ions in the core, the nanomaterial could be used as a contrast agent for magnetic resonance imaging (MRI). Compared with the clinical commercial contrast agent Gd-DTPA, the as-fabricated nanomaterial showed a comparable longitudinal relaxivities value (r(1)) and similar imaging effect.
- Published
- 2012
- Full Text
- View/download PDF
14. Rare-Earth nanoparticles with enhanced upconversion emission and suppressed rare-Earth-ion leakage.
- Author
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Wang YF, Sun LD, Xiao JW, Feng W, Zhou JC, Shen J, and Yan CH
- Subjects
- HeLa Cells, Humans, Luminescent Agents chemistry, Luminescent Measurements, Metals, Rare Earth chemistry, Nanoparticles chemistry, Nanoparticles ultrastructure, Particle Size, Ions chemistry, Luminescent Agents analysis, Metals, Rare Earth analysis, Microscopy, Confocal, Nanoparticles analysis
- Abstract
Upconversion emissions from rare-earth nanoparticles have attracted much interest as potential biolabels, for which small particle size and high emission intensity are both desired. Herein we report a facile way to achieve NaYF(4):Yb,Er@CaF(2) nanoparticles (NPs) with a small size (10-13 nm) and highly enhanced (ca. 300 times) upconversion emission compared with the pristine NPs. The CaF(2) shell protects the rare-earth ions from leaking, when the nanoparticles are exposed to buffer solution, and ensures biological safety for the potential bioprobe applications. With the upconversion emission from NaYF(4):Yb,Er@CaF(2) NPs, HeLa cells were imaged with low background interference., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2012
- Full Text
- View/download PDF
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