다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

12.2.2. Four-Wave Mixing (FWM) 4849 12.2.3. Dye Aggregation 4850 12.2.4. Optoelectronic Nanodevices 4850 12.3. Sensor 4851 12.3.1. Chemical Sensor 4851 12.3.2. Biological Sensor 4851 12.4. Catalysis 4852 13. Conclusion and Perspectives 4852 14. Abbreviations 4853 15. Acknowledgements 4854 16. References 4854 * Corresponding author E-mail: tpal@chem.iitkgp.ernet.in. † Raidighi College. § Indian Institute of Technology. 4797 Chem. Rev. 2007, 107, 4797−4862

Interparticle Coupling Effect on the Surface Plasmon Resonance of Gold Nanoparticles: From Theory to Applications

Uniform, spherical-shaped TiO2:Eu nanoparticles with different doping concentrations have been synthesized through controlled hydrolysis of titanium tetrabutoxide under appropriate pH and temperature in the presence of EuCl3·6H2O. Through air annealing at 500°C for 2 h, the amorphous, as-grown nanoparticles could be converted to a pure anatase phase. The morphology, structural, and optical properties of the annealed nanostructures were studied using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy [EDS], and UV-Visible diffuse reflectance spectroscopy techniques. Optoelectronic behaviors of the nanostructures were studied using micro-Raman and photoluminescence [PL] spectroscopies at room temperature. EDS results confirmed a systematic increase of Eu content in the as-prepared samples with the increase of nominal europium content in the reaction solution. With the increasing dopant concentration, crystallinity and crystallite size of the titania particles decreased gradually. Incorporation of europium in the titania particles induced a structural deformation and a blueshift of their absorption edge. While the room-temperature PL emission of the as-grown samples is dominated by the 5D0 - 7Fj transition of Eu+3 ions, the emission intensity reduced drastically after thermal annealing due to outwards segregation of dopant ions.

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Effects of crystallization and dopant concentration on the emission behavior of TiO2:Eu nanophosphors

Organic–inorganic hybrid materials do not represent only a creative alternative to design new materials and compounds for academic research, but their improved or unusual features allow the development of innovative industrial applications. Nowadays, most of the hybrid materials that have already entered the market are synthesised and processed by using conventional soft chemistry based routes developed in the eighties. These processes are based on: a) the copolymerisation of functional organosilanes, macromonomers, and metal alkoxides, b) the encapsulation of organic components within sol–gel derived silica or metallic oxides, c) the organic functionalisation of nanofillers, nanoclays or other compounds with lamellar structures, etc. The chemical strategies (self-assembly, nanobuilding block approaches, hybrid MOF (Metal Organic Frameworks), integrative synthesis, coupled processes, bio-inspired strategies, etc.) offered nowadays by academic research allow, through an intelligent tuned coding, the development of a new vectorial chemistry, able to direct the assembling of a large variety of structurally well defined nano-objects into complex hybrid architectures hierarchically organised in terms of structure and functions. Looking to the future, there is no doubt that these new generations of hybrid materials, born from the very fruitful activities in this research field, will open a land of promising applications in many areas: optics, electronics, ionics, mechanics, energy, environment, biology, medicine for example as membranes and separation devices, functional smart coatings, fuel and solar cells, catalysts, sensors, etc.

Applications of hybrid organic–inorganic nanocomposites

The detection methods and generation mechanisms of the intrinsic reactive oxygen species (ROS), i.e., superoxide anion radical (•O2–), hydrogen peroxide (H2O2), singlet oxygen (1O2), and hydroxyl radical (•OH) in photocatalysis, were surveyed comprehensively. Consequently, the major photocatalyst used in heterogeneous photocatalytic systems was found to be TiO2. However, besides TiO2 some representative photocatalysts were also involved in the discussion. Among the various issues we focused on the detection methods and generation reactions of ROS in the aqueous suspensions of photocatalysts. On the careful account of the experimental results presented so far, we proposed the following apprehension: adsorbed •OH could be regarded as trapped holes, which are involved in a rapid adsorption–desorption equilibrium at the TiO2–solution interface. Because the equilibrium shifts to the adsorption side, trapped holes must be actually the dominant oxidation species whereas •OH in solution would exert the reactivity...

Generation and Detection of Reactive Oxygen Species in Photocatalysis

Raman and infrared spectroscopy have been employed to investigate the 99.5%[xB2O3(1−x)Bi2O3]0.5%CuO glasses with different Bi/B nominal ratios (0.07⩽x⩽0.625) in order to obtain information about the competitive role of B2O3 and Bi2O3 in the formation of the glass network. The glass samples have been prepared by melting at 1100 °C and rapidly cooling at room temperature. In order to relax the structure, to improve the local order and to develop crystalline phases the glass samples were kept at 575 °C for 10 h. The influence of both Bi2O3 and CuO on the vitreous B2O3 network as well as the local order changes around bismuth and boron atoms in as prepared and heat treated samples was studied. Structural modifications occurring in heat treated samples compared to the untreated glasses have been observed.

Structural investigations of copper doped B2O3–Bi2O3 glasses with high bismuth oxide content

Glass systems of composition 95%[xB2O3(1−x)Bi2O3]5%Fe2O3 with different Bi/B nominal ratios (0.07⩽x⩽0.90) have been investigated by means of Raman and infrared spectroscopy in order to obtain information about the competitive role of B2O3 and Bi2O3 in the formation of the glass network. The glass samples have been prepared by melting at 1100 °C and rapidly cooling at room temperature. The samples have been further kept at 575 °C for 10 h in order to relax the glasses structure as well as to improve the local order and to develop the new formed crystalline phases. The influence of both Bi2O3 and Fe2O3 on the vitreous B2O3 network as well as the local order changes around bismuth and boron atoms in as prepared and heat-treated samples have been studied. Structural modifications occurring in the heat-treated samples compared to the untreated glasses have been pointed out.

Vibrational spectroscopy of highly iron doped B2O3–Bi2O3 glass systems

Gold nanoparticle assemblies with different particle densities were immobilized upon functionalized glass substrates and their morphology and optical properties are analysed with TEM and UV?vis absorption spectroscopy. The efficiency of self-assembled gold colloidal nanoparticles as SERS-active substrates at 633?nm excitation line is evaluated by employing p-aminothiophenol. The average enhancements in the range of 105?107 are consistent with signals being dominated by molecules adsorbed at junctions inside nanoparticle assemblies. We employ an annealing treatment to induce changes in the initial morphology of gold assemblies and produce sensitive LSPR substrate. The sensitivity of the as-prepared substrate to transduce changes of the surrounding medium refractive index is further assessed.

https://iopscience.iop.org/article/10.1088/0957-4484/18/25/255702/pdf

Controlling gold nanoparticle assemblies for efficient surface-enhanced Raman scattering and localized surface plasmon resonance sensors

Gold nanostructured films of various thicknesses (15, 30, and 60 nm) are deposited over regular arrays of polystyrene nanospheres in an attempt to evaluate their potential as SERS-active substrates. Atomic force microscopy is used to topographically characterize the substrates as well as to ensure the thickness of the deposited gold films. The optical response of the prepared substrates recommends their use in SERS experiments with multiple laser lines from visible and NIR spectral domains. The assessment of the substrates' SERS activity is performed by using the 532, 633, and 830 nm excitation lines and different average enhancement factor (EF) values are obtained depending on the film thickness and employed laser line. The 60 nm gold nanostructured film generates the greatest local electromagnetic field confinement under NIR excitation and consequently gives rise to maximum SERS enhancement. The large tunability of surface plasmon excitation combined with the advantage of relatively high exhibited avera...

Lucian Baia

Papers

Structural investigations of copper doped B2O3–Bi2O3 glasses with high bismuth oxide content

Vibrational spectroscopy of highly iron doped B2O3–Bi2O3 glass systems

Controlling gold nanoparticle assemblies for efficient surface-enhanced Raman scattering and localized surface plasmon resonance sensors

Gold Films Deposited over Regular Arrays of Polystyrene Nanospheres as Highly Effective SERS Substrates from Visible to NIR

Structural properties of silver nanoclusters–phosphate glass composites