Stability of radical-functionalized gold surfaces by self-assembly and on-surface chemistry

Surface-enhanced Raman spectroscopy in 3D electrospun nanofiber mats coated with gold nanorods

Nanofibers functionalized by metal nanostructures and particles are exploited as effective flexible substrates for SERS analysis. Their complex three-dimensional structure may provide Raman signals enhanced by orders of magnitude compared to untextured surfaces. Understanding the origin of such improved performances is therefore very important for pushing nanofiber-based analytical technologies to their upper limit. Here we report on polymer nanofiber mats which can be exploited as substrates for enhancing the Raman spectra of adsorbed probe molecules. The increased surface area and the scatte…

金属纳米颗粒功能化三维石墨烯：面向传感器和能源相关应用的多功能平台

Metal Nanoparticle-Functionalized Three-Dimensional Graphene: a versatile platform towards sensors and energy-related applications

该研究首次通过胶体溶液浸渍实现金、钯纳米颗粒对外延三维石墨烯的功能化，验证其高覆盖、低团聚、无污染及530°C热稳定性，为传感、催化和能源应用提供平台。

Capillary nanostamping with spongy mesoporous silica stamps

Classical microcontact printing involves transfer of molecules adsorbed on the outer surfaces of solid stamps to substrates to be patterned. We prepared spongy mesoporous silica stamps that can be soaked with ink and that were topographically patterned with arrays of submicron contact elements. Multiple successive stamping steps can be carried out under ambient conditions without ink refilling. Lattices of fullerene nanoparticles with diameters in the 100 nm range were obtained by stamping C60/toluene solutions on perfluorinated glass slides partially wetted by toluene. Stamping an ethanolic 1…

Density-functional study of adsorption of isocyanides on the gold (111) surface

Density functional theory within the generalized-gradient approximation is used to study the adsorption of the isocyanides CNH and CNCH3 on the gold (111) surface at several coverages. It is found that these molecules are highly selective in their adsorption site preference. Adsorption is possible only at the top site, although binding is rather weak and dipole-dipole repulsion prevents binding at coverages of 1/3 ML and higher. At all other high symmetry sites considered (hcp, fcc, bridge), the isonitriles are not bound. To reveal the main mechanisms of bonding, the isonitriles are compared t…

Effect of ultrasonic irradiation power on sonochemical synthesis of gold nanoparticles

In this work, optimized size distribution and optical properties in colloidal synthesis of gold nanoparticles (GNPs) were obtained using a proposed ultrasonic Tuerkevich-Frens method. The effect of three ultrasound (20 kHz) irradiation powers has been analyzed as size and shape control parameter. The GNPs colloidal solutions were obtained from chloroauric acid (HAuCl$_{4}$) and trisodium citrate ($\rm C_{6}H_{5}Na_{3}O_{7}\cdot 2H_{2}O$) under continuous irradiation for 1 hour without any heat or stirring. The surface plasmon resonance (SPR) was monitored in the UV-Vis spectra every 10 minutes…

Tuning Optical Properties of Self-Assembled Nanoparticle Network with External Optical Excitation

DNA-driven self-assembly enables precise positioning of the colloidal nanoparticles owing to specific Watson-Crick interactions. Another important feature of this self-assembly method is its reversibility by controlling the temperature of the medium. In this work, we study the potential of another mechanism to control binding/unbinding process of the DNA-functionalized gold nanoparticles. We employ the laser radiation that can be absorbed by the gold nanoparticles to heat their network and disassociate it. Here, we show that we can actively control the optical properties of the nanoparticle ne…

Nanostructured submicron block copolymer dots by sacrificial stamping: a potential preconcentration platform for locally resolved sensing, chemistry and cellular interactions

Classical contact lithography involves patterning of surfaces by embossing or by transfer of ink. We report direct lithographic transfer of parts of sacrificial stamps onto counterpart surfaces. Using sacrificial stamps consisting of the block copolymer polystyrene-block-poly(2-pyridine) (PS-b-P2VP), we deposited arrays of nanostructured submicron PS-b-P2VP dots with heights of about 100 nm onto silicon wafers and glass slides. The sacrificial PS-b-P2VP stamps were topographically patterned with truncated-pyramidal contact elements and penetrated by spongy-continuous nanopore systems. The spon…