共查询到20条相似文献,搜索用时 32 毫秒
1.
2.
A method for the synthesis of a new class of anisotropic mesostructured gold material, which we call “mesoflowers”, is demonstrated.
The mesoflowers, unsymmetrical at the single particle level, resemble several natural objects and are made up of a large number
of stems with unusual pentagonal symmetry. The mesostructured material has a high degree of structural purity with star-shaped,
nano-structured stems. The mesoflowers were obtained in high yield, without any contaminating structures and their size could
be tuned from nano- to meso-dimensions. The dependence of various properties of the mesoflowers on their conditions of formation
was studied. The near-infrared-infrared (NIR-IR) absorption exhibited by the mesoflowers has been used for the development
of infrared filters. Using a prototypical device, we demonstrated the utility of the gold mesoflowers in reducing the temperature
rise in an enclosure exposed to daylight in peak summer. These structures showed a high degree of surface-enhanced Raman scattering
(SERS) activity compared to spherical analogues. SERS-based imaging of a single mesoflower is demonstrated. The high SERS
activity and NIR-IR absorption property open up a number of exciting applications in diverse areas.
Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/ and is accessible free of charge. 相似文献
3.
利用具有准周期结构的硅纳米孔柱阵列(silicon nanoprous pillar array,Si-NPA)为衬底使用浸渍法制备优化Au/Si-NPA活性基底。并利用最优化制备的Au/Si-NPA活性基底对罗丹明6G(Rhoda-mine 6G,R6G)进行探测,研究其表面增强拉曼散射(surface enhanced Raman scattering,SERS)光谱并对其增强原理进行解释。 相似文献
4.
Ya Deng Minjiang Chen Jian Zhang Zihao Wang Wenbin Huang Yun Zhao Jean Pierre Nshimiyimana Xiao Hu Xiannian Chi Gu Hou Xueyao Zhang Yanjun Guo Lianfeng Sun 《Nano Research》2016,9(6):1682-1688
The size and density of Ag nanoparticles on n-layer MoS2 exhibit thicknessdependent behavior. The size and density of these particles increased and decreased, respectively, with increasing layer number (n) of n-layer MoS2. Furthermore, the surface-enhanced Raman scattering (SERS) of Ag on this substrate was observed. The enhancement factor of this scattering varied with the thickness of MoS2. The mechanisms governing the aforementioned thickness dependences are proposed and discussed. 相似文献
5.
Active surface-enhanced Raman scattering (SERS) substrates, 3D nano-arrays of Ag nanoparticles (NPs) and graphene quantum dots (GQDs), were prepared using a photochemical approach and an electrophoresis deposition technique with the formation mechanism addressed. The GQDs (ca. 6?nm average) fit into the inter-particle gaps between Ag NPs, as verified by their scanning electron microscopy and high-resolution transmission electron microscopy. This deliberately designed 3D assembly of Ag NPs and GQDs could promote the synergistic effects of both components to further enhance the SERS performances according to both electromagnetic mechanism and chemical mechanism. Preliminary experiments show that the 3D substrates exhibited strong SERS signals comparing with bare Si substrates. This work provides a promising way for 3D SERS substrates. 相似文献
6.
Ag2S–Graphene nanocomposite was prepared via a relatively facile hydrothermal method, using a single-source molecular (silver diethyldithiocarbamate [Ag(DDTC)]) as precursor and graphene sheets as a support material. The composite was characterized by X-ray power diffraction, X-ray photoelectron spectroscopy, Field-emission scanning electron microscope, transmission electron microscopy, Fourier transform infrared, Raman spectra and fluorescence spectroscopy. The experimental results show that the Ag2S–Graphene nanocomposite displays surface-enhanced Raman scattering (SERS) activity for graphene oxide and reveals relatively better fluorescence property compared with pure Ag2S. 相似文献
7.
V. Izquierdo-RocaR. Caballero X. FontanéC.A. Kaufmann J. Álvarez-GarcíaL. Calvo-Barrio E. SaucedoA. Pérez-Rodríguez J.R. Morante H.W. Schock 《Thin solid films》2011,519(21):7300-7303
This work reports the Raman scattering surface and in-depth resolved analysis of Cu-poor Cu(In,Ga)Se2 (CIGS) grown on polyimide substrates. In order to study the effect of Na on the formation and microstructure of the CIGS and the corresponding Cu-poor ordered vacancy compound (OVC) phases, a NaF precursor layer with different thicknesses was deposited on the Mo-coated substrates before growing of the samples. The Raman spectroscopy data are correlated with the analysis of the samples by Auger electron spectroscopy and scanning electron microscopy. These data corroborate the significant role of Na on the inhibition of Ga-In interdiffusion and on the formation of the MoSe2 interfacial phase at the back region of the layers. Presence of Na also leads to an enhancement in the formation of the chalcopyrite CIGS phase and a decrease in the occurrence of the dominant OVC phase at the surface region. This study confirms the strong dependence of the microstructure and phase distribution in CIGS absorber layers on the Na available during their growth. 相似文献
8.
V. Izquierdo-Roca J. Álvarez-García A. Pérez-Rodríguez J.R. Morante E. Saucedo V. Bermúdez 《Thin solid films》2009,517(7):2163-7275
Single step electrodeposition (ED) of Se-rich CuInSe2 precursors, followed by RTP annealing under sulphurising conditions leading to S-rich CuIn(S,Se)2 films, constitutes a promising technology for low cost high efficiency solar cells. In this work, a Raman scattering (RS) analysis of Se rich precursors grown under ED conditions leading to different chemical compositions is reported. RS has allowed identification of the main secondary phases in these layers with elemental Se, Cu-Se binary and ordered vacancy compound (OVC) phases. The experimental data show a strong dependence of the spectral contributions related to Se and Cu-Se with the layer molecularity, and the formation of these phases is mainly determined by the content of excess Se in the layers. The correlation of these data with the characteristics of the solar cells fabricated with these precursors, shows the strong impact of the presence of the Cu-Se phase on the performance of the final devices. These results point out the key role played by this binary phase on the formation of secondary phases after the sulphurising step. 相似文献
9.
Y Kitaoka K Mizuuchi T Yokoyama K Yamamoto K Narumi M Kato 《Bulletin of Materials Science》1999,22(3):405-411
The resistance to photorefractive damage is investigated for several nonlinear crystals. A quasi-phase-matched (QPM) second
harmonic generation (SHG) waveguide device is fabricated in 5 mol% Mg-doped LiNbO3 which has high resistance to optical damage. The SHG blue laser of the QPM-SHG waveguide device and a tunable distributed
Bragg reflector (DBR) laser diode is demonstrated, wherein output stability of continuous blue light is measured. The SHG
blue laser, using the QPM-SHG waveguide device with broadened flat matching response, shows good modulation characteristics.
The pulsed peak power of 23 mW with rectangular modulated waveform is generated. The SHG blue laser is installed to an optical
head, and good recording and readout characteristics are demonstrated. Moreover, butt-coupled SHG blue laser is examined to
gain a miniature module with volume of 0·8 cc. 相似文献
10.
Highly dispersible Eu3+-doped CaMoO4@Au-nanorod hybrid nanoparticles (HNPs) exhibit optical properties, such as plasmon resonances in the near-infrared region at 790 nm and luminescence at 615 nm, offering multimodal capabilities: fluorescence imaging, surface-enhanced Raman spectroscopy (SERS) detection and photothermal therapy (PTT). HNPs were conjugated with a Raman reporter (4-mercaptobenzoic acid), showing a desired SERS signal (enhancement factor 5.0 × 105). The HNPs have a heat conversion efficiency of 25.6%, and a hyperthermia temperature of 42°C could be achieved by adjusting either concentration of HNPs, or laser power, or irradiation time. HNPs were modified with antibody specific to cancer biomarker epidermal growth factor receptor, then applied to human lung cancer (A549) and mouse hepatocyte cells (AML12), and in vitro PTT effect was studied. In addition, the biomechanical properties of A549 cells were quantified using atomic force microscopy. This study shows the potential applications of these HNPs in fluorescence imaging, SERS detection, and PTT with good photostability and biocompatibility. 相似文献
11.
In the present work we report the results of the growth, morphological and structural characterization of Cu2ZnSnS4 (CZTS) thin films prepared by sulfurization of DC magnetron sputtered Cu/Zn/Sn precursor layers. The adjustment of the thicknesses and the properties of the precursors were used to control the final composition of the films. Its properties were studied by SEM/EDS, XRD and Raman scattering. The influence of the sulfurization temperature on the morphology, composition and structure of the films has been studied. With the presented method we have been able to prepare CZTS thin films with the kesterite structure. 相似文献
12.
Andreas Talkenberger Cameliu HimcinschiTorsten Weißbach Kannan VijayanandhiniIonela Vrejoiu Christian RöderDavid Rafaja Jens Kortus 《Thin solid films》2012,520(14):4590-4594
Epitaxial BiCrO3 thin films were grown onto NdGaO3 (110)- and (LaAlO3)0.3-(Sr2AlTaO6)0.7 (100)-oriented substrates by pulsed laser deposition. High resolution X-ray diffraction and pole figure measurements were performed in order to obtain information about the crystal structure of the films, about their quality and about the mutual crystallographic orientation between the films and the substrates. The monoclinic (111) plane of BiCrO3 was found out to be parallel to the substrate surface. The epitaxial relation between films and substrates was verified by using polarisation dependent Raman spectroscopic experiments and theoretical calculations based on symmetry. 相似文献
13.
Carsten Dubs Jens-Peter Ruske Jürgen Krußlich Andreas Tünnermann 《Optical Materials》2009,31(11):1650-1657
The fabrication of epitaxially grown Zn-substituted LiNbO3 (Zn:LiNbO3) waveguide films and rib waveguides is reported and detailed investigations about microstructure, morphology and optical waveguide properties are provided. Zn:LiNbO3 films were grown on congruent X-cut LiNbO3 substrates by a modified liquid phase epitaxy in solid–liquid coexisting solutions. The homogeneously Zn-substituted films exhibit high crystalline perfection and extremely flat surfaces with averaged surface roughness of rms = 0.2–0.3 nm. At the film/substrate interface a Zn-containing transient layer has been observed, which allows the growth of elastically strained Zn:LiNbO3 film lattices. X-ray diffraction reciprocal-space measurements prove the pseudomorphic film growth. The refractive index difference between substrate and film depends on the zinc substitution content, which increase with rising growth temperatures. For films with 5.3 mol% Zn (Δno ≈ +5 × 10−3) only ordinary ray propagation was observed, while for films with 7.5 mol% Zn (Δno ≈ +8 × 10−3, Δne ≈ +5 × 10−3) both modes, TM and TE propagate. Stress-induced refractive index changes are in the order of Δn ≈ 10−4. In rib waveguide microstructures singlemode propagation with nearly symmetrical field distribution has been observed. To demonstrate the potential of the proton exchange-assisted dry-etching technique interferometer microstructures were fabricated. 相似文献
14.
Glasses with the nominal compositions of xWO325La2O3(75 − x)B2O3 (mol%) with x = 15, 25, and 50 were prepared using a conventional melt quenching method, and their structure and crystallization behavior were examined from Raman scattering spectra and X-ray diffraction analyses. The glasses are colorless in the visible light region and give the optical band gap energy of 3.49-3.61 eV. The glass transition and crystallization temperatures and the thermal stability against crystallization decrease with increasing WO3 content. The strong Raman bands at 840 and 940-960 cm−1 suggest that the main coordination state of W6+ ions in the glasses is isolated (WO4)2− tetrahedral units. The formation of WO6 octahedral units is also suggested in the glasses with high WO3 contents. The main crystallization mechanism in the glasses is the surface crystallization, and the glass of 50WO325La2O325B2O3 shows the crystallization of LaBWO6 single phase. The present study proposes that WO3La2O3B2O3 glasses and crystallized glasses are very interesting as optical functional materials. 相似文献
15.
The Nd2O3 modified ZrO2 was synthesized using two methods of co-precipitation (Nd-ZrO2) and wet impregnation (Nd/ZrO2). The surface and bulk crystalline phases of Nd2O3 modified ZrO2 were investigated by using UV Raman spectroscopy, visible Raman spectroscopy, and X-ray diffraction (XRD). It is observed that the tetragonal phase in the surface region of Nd-ZrO2 was not effectively stabilized by Nd2O3, as Nd2O3 is mainly present in the bulk of Nd-ZrO2. However, in Nd/ZrO2, it is found that with the impregnation of 0.5 mol% Nd2O3 on ZrO2, the surface tetragonal phase of Nd/ZrO2 can be stabilized even after calcination at 700 °C. The UV Raman results indicate that a disordered structure, or intermediate structure, which is involved in the transition from the tetragonal to the cubic phase, is formed at the surface region of Nd/ZrO2. The formation of the aforementioned intermediate structure inhibits the phase transition from tetragonal to monoclinic in the surface region of Nd/ZrO2. Furthermore, it is observed that the mixed tetragonal and monoclinic phases in the surface region of ZrO2 which has been impregnated with Nd2O3 can also be stabilized after calcination at 700 °C. This work provides a simple method for controlling the surface phase of ZrO2 at high temperatures. 相似文献
16.
Hao Yong YinXu Chun Song Yi Fan ZhengXia Wang Zhi Ai YangRong Ma 《Materials Science and Engineering: B》2011,176(8):684-687
Organic/inorganic nanocomposite films based on poly(3-methoxythiophene) (PMOT) and WO3 were prepared by a consecutive two-step electrochemical method. The products were characterized in detail by scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS) and Fourier-transform infrared spectroscopies (FTIR). The results show that the PMOT/WO3 nanocomposite films consist of two layers, the substrate WO3 with 30 nm grains and superstratum PMOT, which average grain size is 60 nm. The obtained PMOT/WO3 nanocomposite films were also characterized by cyclic voltammetry to investigate their electrochemistry properties which display significant enhancement of electrochemical activity than that of pure PMOT and WO3 films. 相似文献
17.
Chen-zhong Yao Bo-Hui WeiHui-xuan Ma Qiao-juan GongKang-wen Jing Hong SunLi-xin Meng 《Materials Letters》2011,65(3):490-492
Hexagonal and vertically aligned La(OH)3 nanorod arrays have been fabricated in a large scale via a simple electrochemical method without any hard templates and surfactants. By the aid of potential-time curve, a possible formation process of the La(OH)3 nanorod arrays is proposed, and the gas bubbles functioning as a dynamic template might be responsible for the growth of ordered La(OH)3 nanorods. The total absorption capacities of the as-prepared products for Congo red is about 73.5 mg g− 1, which shows an environmental engineering application in removing organic dye from water. In short, this synthetic method shows prominent advantages such as its low-cost, easy preparation, good adherence and suitability for preparing other nanoarrays. 相似文献
18.
In this work ITO thin films have been grown onto glass, polyethylene terephthalate (PET) and Arylite polymer substrates by sputtering at room temperature.The In2S3 films were chemically deposited on ITO during different times, forming bilayers for subsequent photovoltaic applications. Optical properties of the films were investigated from the transmittance and the structural properties by XRD. Transmittance of the films varies with deposition time and the different substrates used, the same as the adherence and the homogeneity of the films. 相似文献
19.
Effects of Ho2O3 addition on defects of BaTiO3 ceramic have been studied in terms of electrical conductivity at 1200 °C as a function of oxygen partial pressure (PO2°) and oxygen vacancy concentration. The substitution of Ho3+ for the Ti site in Ba(Ti1−xHox)O3−0.5x resulted in a significant shift of conductivity minimum toward lower oxygen pressures and showed an acceptor-doped behavior. The solubility limit of Ho on Ti sites was confirmed less than 3.0 mol% by measuring the electrical conductivity and the lattice constant. Oxygen vacancy concentrations were calculated from the positions of PO2° in the conductivity minima and were in good agreement with theoretically estimated values within the solubility limit. The Curie point moved to lower temperatures with increasing the oxygen vacancy concentration and Ho contents. 相似文献
20.
E.K. Evangelou M.S. Rahman A. Dimoulas K.P. Giannakopoulos R. Valicu 《Thin solid films》2010,518(14):3964-3971
In the present work we report on the structural and electrical properties of metal-oxide-semiconductor (MOS) devices with HfO2/Dy2O3 gate stack dielectrics, deposited by molecular beam deposition on p-type germanium (Ge) substrates. Structural characterization by means of high-resolution Transmission Electron Microscopy (TEM) and X-ray diffraction measurements demonstrate the nanocrystalline nature of the films. Moreover, the interpretation of the X-ray reflectivity measurements reveals the spontaneous growth of an ultrathin germanium oxide interfacial layer which was also confirmed by TEM. Subsequent electrical characterization measurements on Pt/HfO2/Dy2O3/p-Ge MOS diodes show that a combination of a thin Dy2O3 buffer layer with a thicker HfO2 on top can give very good results, such as equivalent oxide thickness values as low as 1.9 nm, low density of interfacial defects (2-5 × 1012 eV− 1 cm− 2) and leakage currents with typical current density values around 15 nA/cm2 at Vg = VFB − 1V. 相似文献