共查询到20条相似文献，搜索用时 0 毫秒
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Evangelia Xenogiannopoulou Kostas Iliopoulos Stelios Couris Tanya Karakouz Alexander Vaskevich Israel Rubinstein 《Advanced functional materials》2008,18(8):1281-1289
Films of gold nanoscaled islands with thicknesses ranging between 0.5 and 15 nm were prepared by thermal evaporation onto untreated and aminosilane‐pretreated glass substrates. Post‐deposition annealing was found to modify the morphological characteristics of the islands (e.g., average island area and height, inter‐island distance, etc.), resulting in changes of the localized surface plasmon resonance (SPR) characteristics and, therefore, modifying the nonlinear optical (NLO) response of the films. The NLO response of both unannealed and annealed (20 h at 200 °C) films was studied by means of the optical Kerr effect (OKE), using 35 ps, 532 nm laser excitation, while measurements performed by means of the Z‐scan technique allowed for the determination of both the nonlinear refraction and absorption characteristics of the films. The results are discussed and compared with other reports. 相似文献
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Somsubhra Maity Jason R. Bochinski Laura I. Clarke 《Advanced functional materials》2012,22(24):5259-5270
The photothermal effect of metal nanoparticles embedded in polymeric materials can be used to efficiently generate local heat for in situ thermally processing within an existing material. Fluorescent probes are employed as thermal sensors to allow dynamical measurement of the amplitude and rate of temperature change within the polymer matrix. The efficacy of this technique is demonstrated in polymer nanocomposite samples with different morphological characteristics, namely nanofibrous mats and thin film samples. For similarly thick materials and both types of sample morphology, average temperature increases on the order of ≈100s °C are readily obtained with dilute nanoparticle concentrations under relatively low irradiation intensity. Thus, the in situ photothermal heating approach has great potential for controllably driving a multitude of thermal processes, such as triggering phase transitions, generating site‐specific cross‐linking, or initiating chemical reactions from within a material. 相似文献
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Fan Li Hao Pei Lihua Wang Jianxin Lu Jimin Gao Bowei Jiang Xingchun Zhao Chunhai Fan 《Advanced functional materials》2013,23(33):4140-4148
A variety of nanomaterials have shown extraordinarily high quenching ability toward a broad range of fluorophores. Recently, there has been intense interest in developing new tools for fluorescent DNA analysis in solution or inside the cell based on this property, and by exploiting interactions between these nanoscale “superquenchers” and DNA molecules in the single‐stranded (ss‐) or double‐stranded (ds‐) forms. Here, a comparative study on the nanoqueching effects is performed by using a series of nanomaterials with different dimensions, i.e., gold nanoparticles (AuNPs, 0D), carbon nanotubes (CNTs, 1D), and graphene oxide (GO, 2D). The quenching efficiency, kinetics, differentiation ability, and influencing factors such as concentration and ionic strength are studied. Interestingly, GO exhibits superior quenching abilities to the other two materials in both the quenching efficiency and kinetics. As a result, a GO‐based fluorescent sensor, designed in a simple mix‐and‐detect format, can detect concentrations of DNA as low as 0.2 nM , which is better than either CNTs or AuNPs by an order of magnitude. This sensor can also differentiate single‐base mismatches much better than either CNTs‐ or AuNPs‐ based sensors. This study paves the way to better choice of nanomaterials for bioanalysis and elaborate design of biosensors for both in vitro diagnosis and in vivo bioimaging. 相似文献
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Hongcheng Pan Hongyu Lin Qingming Shen Jun‐Jie Zhu 《Advanced functional materials》2008,18(22):3692-3698
Luminescent cadmium(II) (8‐hydroxyquinoline) chloride (CdqCl) complex nanowires are synthesized via a sonochemical solution route. The results of X‐ray photoelectron spectroscopy, energy dispersive X‐ray analysis, infrared spectroscopy, elemental analysis (EA), and atomic absorption spectroscopy demonstrate that the chemical composition of the product is Cd(C9H6NO)Cl. Transmission electron microscopy and scanning electron microscopy images show that the CdqCl product is wire‐like in structure, with a diameter of approximately 50 nm and an approximate length of 2–4 µm. The morphology and composition of the product can be transformed from Cdq2 micrometer‐scaled flakes to CdqCl nanowires by increasing the ratio of CdCl2/q. A new fluorescent sensing strategy for detecting H2O2 and glucose is developed and is based on the combination of the luminescent nanowires and the biocatalytic growth of Au nanoparticles. The quenching effects of Au nanoparticles and on the fluorescence of CdqCl nanowires are investigated. The dominant factor for the fluorescence quenching of CdqCl nanowires is that the Stern–Volmer quenching constant of Au nanoparticles is larger than that of . 相似文献
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Dehui Wan Hsuen‐Li Chen Yu‐Ting Lai Chen‐Chieh Yu King‐Fu Lin 《Advanced functional materials》2010,20(11):1742-1749
A flexible surface plasmon resonance (SPR)‐based scattering waveguide sensor is prepared by directly imprinting hollow gold nanoparticles (NPs) and solid gold NPs onto flexible polycarbonate (PC) plates—without any surface modification—using a modified reversal nanoimprint lithography technology. Controlling the imprinting conditions, including temperature and pressure, allows for the fine adjustment of the depths of the embedded metal NPs and their SPR properties. This patterning approach exhibits a resolution down to the submicrometer level. A 3D finite‐difference time domain simulation is used to examine the optical behavior of light propagating parallel to the air/substrate interface within the near‐field regime. Consistent with the simulations, almost an order of magnitude enhancement in the scattering signal after transferring the metal NPs from the glass mold to the PC substrate is obtained experimentally. The enhanced signal is attributed to the particles' strong scattering of the guiding‐mode waves (within the waveguide) and the evanescent wave (above the waveguide) simultaneously. Finally, the imprinting conditions are optimized to obtain a strongly scattering bio/chemical waveguide sensor. 相似文献
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Blair D. Johnston Wolfgang G. Kreyling Christian Pfeiffer Martin Schäffler Hakan Sarioglu Simon Ristig Stephanie Hirn Nadine Haberl Stefanie M. Hauck Matthias Epple Jonas Hühn Wolfgang J. Parak 《Advanced functional materials》2017,27(42)
To study the influence of colloidal stability on protein corona formation, gold nanoparticles are synthesized with five distinct surface modifications: coating with citric acid, bis(p‐sulfonatophenyl)phenylphosphine dihydrate dipotassium salt, thiol‐terminated methoxy‐polyethylene glycol, dodecylamine‐grafted poly(isobutylene‐alt‐maleic anhydride), and dodecylamine‐grafted poly(isobutylene‐alt‐maleic anhydride) conjugated with polyethylene glycol. The nanoparticles are incubated with serum or bronchoalveolar lavage fluid from C57BL/6 mice (15 min or 24 h) to assess the effect of differential nanoparticle surface presentation on protein corona formation in the air–blood barrier exposure pathway. Proteomic quantification and nanoparticle size measurements are used to assess protein corona formation. We show that surface modification has a clear effect on the size and the composition of the protein corona that is related to the colloidal stability of the studied nanoparticles. Additionally, differences in the composition and size of the protein corona are shown between biological media and duration of exposure, indicating evolution of the corona through this exposure pathway. Consequently, a major determinant of protein corona formation is the colloidal stability of nanoparticles in biological media and chemical or environmental modification of the nanoparticles alters the surface presentation of the functional epitope in vivo. Therefore, the colloidal stability of nanoparticles has a decisive influence on nano–bio interactions. 相似文献
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Giuseppe V. Bianco Maria M. Giangregorio Maria Losurdo Pio Capezzuto Giovanni Bruno 《Advanced functional materials》2012,22(24):5081-5088
A novel dry plasma methodology for fabricating directly stabilized substrate‐supported gold nanoparticle (NP) ensembles for near infrared surface enhanced Raman scattering (NIR SERS) is presented. This maskless stepwise growth exploits Au‐sulfide seeds by plasma sulfidization of gold nuclei to produce highly faceted Au NPs with a multiple plasmon resonance that can be tuned from the visible to the near infrared, down to 1400 nm. The role of Au sulfidization in modifying the dynamics of Au NPs and of the corresponding plasmon resonance is discussed. The tunability of the plasmon resonance in a broad range is shown and the effectiveness as substrates for NIR SERS is demonstrated. The SERS response is investigated by using different laser sources operating both in the visible and in the NIR. SERS mapping of the SERS enhancement factor is carried out in order to evaluate their effectiveness, stability, and reproducibility as NIR SERS substrates, also in comparison with gold NPs fabricated by conventional sputtering and with the state‐of‐the‐art in the current literature. 相似文献
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Belén Fernández Natividad Gálvez Rafael Cuesta Ana B. Hungría José J. Calvino José M. Domínguez‐Vera 《Advanced functional materials》2008,18(24):3931-3935
A new class of water‐soluble, fluorescent, magnetic quantum dots––magnetoferritin bioconjugate––is prepared. The nanostructures are patterned mainly as dimer particles as characterized by high‐angle annular dark‐field scanning transmission electron microscopy and electron energy loss spectroscopy. Magnetic (high spontaneous magnetization values, superparamagnetism) and fluorescent (narrow emission peaks, uniform brightness) properties of both nanoblocks are maintained in the final nanostructure. 相似文献
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Otto L. Muskens Matt W. England Lefteris Danos Mei Li Stephen Mann 《Advanced functional materials》2013,23(3):281-290
Metal‐infiltrated protein crystals form a novel class of bio‐nanomaterials of great interest for applications in biomedicine, chemistry, and optoelectronics. As yet, very little is known about the internal structure of these materials and the interconnectivity of the metallic network. Here, the optical response of individual Au‐ and Ag‐infiltrated cross‐linked lysozyme crystals is investigated using angle‐ and polarization‐dependent spectroscopy. The measurements unequivocally show that metallic inclusions formed inside the nanoporous solvent channels do not connect into continuous nanowires, but rather consist of ensembles of isolated spheroidal nanoclusters with aspect ratios as high as a value of four, and which exhibit a pronounced plasmonic response that is isotropic on a macroscopic length scale. Fluorescence measurement in the visible range show a strong contribution from the protein host, which is quenched by the Au inclusions, and a weaker contribution attributed to the molecule‐like emission from small Au‐clusters. 相似文献
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Ronghui Que Mingwang Shao Shujuan Zhuo Chunye Wen Suidong Wang Shuit‐Tong Lee 《Advanced functional materials》2011,21(17):3337-3343
A facile method based on capillarity‐assisted assembly is used to fabricate high‐performance surface‐enhanced Raman scattering (SERS) substrates employing clean Au nanoparticles (NPs). This method is better than micro‐channel way because the former may supply large‐area uniform assembly and overcome the uneven radial distribution. Such densely‐arranged assembly of Au NPs exhibits high reproducibility and large Raman enhancement factors of 3 × 1010, arising from strong electromagnetic field coupling induced by adjacent Au NPs. The spot‐to‐spot SERS signals show that the relative standard deviation (RSD) in the intensity of the main Raman vibration modes (1310, 1361, 1509, 1650 cm?1) of Rhodamine 6G at a concentration of 1 × 10?10 M are consistently less than 20%, demonstrating good spatial uniformity and reproducibility. The SERS signals of sudan dye at a 1 × 10?8 M concentration also shows high reproducibility with a low RSD of <20%. Further, the assembly substrate is stable, retaining excellent uniformity and sensitivity after storage for months. This assembly strategy integrating the advantages of low‐cost production, high sensitivity, and reproducibility would significantly facilitate practical SERS detection. 相似文献
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纳米银颗粒表面增强荧光效应与其覆盖率的关联 总被引：2，自引：2，他引：0
实验上获得了纳米银颗粒对光敏剂二氢卟吩f-甲醚（CPD4）的荧光增强效应,基于纳米银颗粒覆盖率对表面增强荧光效应的影响,初步探讨了荧光增强的物理增强机制。不同覆盖率纳米银基底表面吸附的CPD4的增强荧光结果显示,在低颗粒覆盖率时（〈30％）,激发效率和激发态分子衰减速率不依赖于覆盖率变化;当颗粒覆盖率大于30％接近40％时,激发效率和激发态分子衰减速率都得到提高。实验和理论结果均表明,相比于单个银纳米颗粒,颗粒覆盖率增加提高了颗粒间电磁耦合效应,能够产生更强的表面增强荧光效应。 相似文献
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Niklas O. Junker Anja Lindenau Michael Rütten Marcel Lach Alexander Nedilko Dmitry N. Chigrin Gero von Plessen Tobias Beck 《Advanced functional materials》2023,33(43):2303260
The optical properties of 3D metacrystals made of gold nanoparticles in protein nanocages are studied. These metacrystals have sizes of tens of micrometers and are of high structural and optical quality. Through microspectroscopy measurements and model calculations it is demonstrated that the metacrystals show plasmonic absorption in the green wavelength range and are largely transparent in the red and infrared ranges. By using empty nanocages as placeholders in the metacrystal lattice, it is possible to control how strongly the metamaterial absorbs. Measurements on a pyramidal metacrystal show that it deflects visible light. The deflection shows evidence for anomalous refraction at short wavelengths and normal refraction at long wavelengths. The refractive dispersion is ascribed to the optical dispersion relation of the plasmonic metamaterial. 相似文献
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Jierui Fu Niuzhuang Yang Yue Liu Quan Liu Jiaxin Du Yuqiang Fang Jiapeng Wang Bo Gao Chengyan Xu Dai Zhang Alfred J. Meixner Gaoyang Gou Fuqiang Huang Liang Zhen Yang Li 《Advanced functional materials》2024,34(3):2308207
2D in-plane ferroelectric NbOI2 exhibits strong second harmonic generation (SHG) and ultrahigh effective susceptibility. To push forward their applications in nonlinear photonics and optoelectronics, it is highly desirable to understand the emission dipole orientation and tunability of SHG, which is not achieved. Here, by integrating tight focusing from parabolic mirror with back focal plane (BFP) imaging technique, for the first time it is demonstrated that SHG emission of NbOI2 presents purely in-plane dipole orientation in consistent with numerical simulations, suggesting the in-plane components of the SHG susceptibility tensor in NbOI2 dominate the emission. Moreover, with the aid of ab-initio calculations, it is found that the hydrostatic pressure can dramatically change the structure and resultant SHG intensity of NbOI2. Explicitly, SHG intensity endures a slight increase due to the distortion of octahedral at low pressure pressure, and then monotonously decreases due to the improvement of structural symmetry with further increasing pressure, and drastically quenching resulting from the ferroelectric to paraelectric phase transition. This work unambiguously demonstrates the dipole emission behavior of SHG and the relationship between structural evolution and SHG intensity, which provides an avenue for tunable nonlinear optics and optoelectronics. 相似文献
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Marlne Palluel Ngoc Minh Tran Nathalie Daro Sonia Buffire Stphane Mornet Eric Freysz Guillaume Chastanet 《Advanced functional materials》2020,30(17)
Rod‐like gold nanoparticles are directly embedded in a 1D‐polymeric spin crossover (SCO) material leading to singular Au@SCO nanohybrid architectures. The resulting architectures are designed to promote a synergetic effect between ultrafast spin‐state photoswitching and photothermal properties of plasmonic nanoparticles. This synergy is evidenced by the strong modulation of the surface plasmon resonance of the gold nanorods through the spin‐state switching of the SCO component and also the strong enhancement of the photoswitching efficiency compared to pure SCO particles. This remarkable synergy results from the large modulation of the dielectric properties of the SCO polymer upon its thermal switching and the enhancement of the heating of these hybrid nanostructures upon excitation of the surface plasmon resonance of the gold nanorods. 相似文献
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The oxygen evolution reaction (OER) is of great importance for renewable energy conversion and storage; however, the intrinsic process is sluggish and suffers from severe efficiency loss as well as large overpotentials. In this work, with the introduction of the plasmonic effects by design of the Au‐MnO2 hybrid catalysts, it is demonstrated that this photophysical phenomenon could largely promote the confinement of the outer electrons of Mn cations by plasmonic “hot holes” generated on gold surface. These “hot holes” work as the effective electron trapper to form the active Mnn+ species which could provide active sites to extract electrons from OH? and eventually facilitate the electrochemical OER catalysis under low laser power. By tuning the laser intensity from 100 to 200 mW, the overpotential is decreased from 0.38 to 0.32 V, which is comparable to IrO2 and RuO2 catalysts. These findings may provide insights into activation of plasmon‐promoted electrocatalysis under low power laser irradiation/treatment and the design of novel composite electrocatalysts. 相似文献
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Wei Zhong Lie Chen Shuqin Xiao Liqiang Huang Yiwang Chen 《Advanced functional materials》2015,25(21):3164-3171
Spin‐coated film of poly(vinylidenefluoride‐hexafluoropropylene) (P(VDF‐HFP)) acts as a cathode/anode buffer layer in polymer solar cells (PSCs) with conventional/inverted device structures. Such devices show optimized performances comparable with the controlled device, making P(VDF‐HFP) a good substitute for LiF/MoO3 as a cathode/anode buffer layer. Ultraviolet photoelectron spectroscopy (UPS) and Kelvin force microscope (KFM) measurements show that increased surface potential of active layers improves cathode contact. In piezoresponse force microscopy (PFM) measurement, P(VDF‐HFP) responds to applied bias in phase curve, showing tunable dipole. This tunable dipole renders surface potential under applied bias. As a result, open‐circuit voltage of devices alters instantly with poling voltage. Moreover, positive poling of P(VDF‐HFP) together with simultaneous oxidation of Ag gradually improves performance of inverted structure device. Integer charge transfer (ICT) model elucidates improved electrode contacts by dipole tuning, varying surface potential and vacuum level shift. Understanding the function of dipole makes P(VDF‐HFP) a promising and versatile buffer layer for PSCs. 相似文献
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提出一种能够准确预测超材料吸收结构光谱响应和共振特性的RLC等效电路模型理论,对其设计进行了扩展,同时详细表征了该模型中的参数。利用该模型,我们对不同尺寸超材料吸波材料的响应波长和带宽进行了计算。与有限差分时域（FDTD）模拟结果相比较,结果吻合很好。所设计的吸收器采用微纳制造工艺制备,通过实验测试,在波长为9.28 μm时,吸收率超过90%。我们将预测结果与测试结果进行对比,表明两者的共振响应具有较好的一致性,从而证实了该模型的合理性和准确性。 相似文献
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Due to the surface‐enhanced Raman scattering (SERS) effect, SERS labels based on noble‐metal nanoparticles loaded with Raman‐active molecules are good candidates for ultrasensitive multiplexed assays and in vitro/in vivo imaging. However, understanding how to maximize the brightness of such labels is of paramount importance for their widespread application. The effective differential Raman scattering cross‐section (dσR/dΩ) of SERS labels made of pegylated gold nanoparticles loaded with various Raman active molecules (Raman reporters) is studied. It is found that proper choice of the Raman reporter and of nanoparticle size can enhance the dσR/dΩ by several orders of magnitude. The experimental results are understood by considering the molecular cross‐section for resonant Raman scattering and the local electromagnetic enhancement factor (GSERS) in the nearby of gold nanoparticles. These results are useful to guide the design of SERS labels with improved performances and to provide a reference for the comparison of the absolute value of the dσR/dΩ of SERS labels based on metal nanoparticles. 相似文献