Room temperature synthesis of blue and green emitting CsPbBr perovskite nanocrystals confined in mesoporous alumina film.

This communication reports the room temperature synthesis of stable CsPbBr3 nanocrystals inside a wormhole mesoporous alumina thin film, showing tunable blue and green emission. The choice of suitable solvents and precursor incorporation sequence enables the generation of CsPbBr3 nanocrystals at room temperature inside the mesoporous alumina film, whereas the tunable emissive property can be attributed to the size increment of the nanocrystals promoted by differing precursor concentrations.

V-shaped active plasmonic meta-polymers.

We report the design and fabrication of V-shaped plasmonic meta-polymers on a glass substrate or silicon wafer using a surface functionalization approach. The efficacy of the assembly method is examined by analyzing the surface enhanced Raman scattering by an individual V-shaped antenna experimentally and using computational simulations to determine the polarization dependence of local electromagnetic field enhancement.

Tunable Au-Ag nanobowl arrays for size-selective plasmonic biosensing.

Selectivity is often a major obstacle for localized surface plasmon resonance-based biosensing in complex biological solutions. An additional degree of selectivity can be achieved through the incorporation of shape complementarity on the nanoparticle surface. Here, we report the versatile fabrication of substrate-bound Au-Ag nanobowl arrays through the galvanic ion replacement of silver nanodisk arrays.

Capping agent-free gold nanostars show greatly increased versatility and sensitivity for biosensing.

We report the first assessment of the plasmonic biosensing capabilities of capping agent-free gold nanostars. Capping agent removal was carried out using aqueous solutions of sodium borohydride, which yielded a refractive index sensitivity of 474 nm/RIU for the polyvinylpyrrolidone (PVP)-free nanostars compared with 98 nm/RIU for PVP-coated gold nanostars. Following PVP removal, biotinylated thiol and streptavidin protein were added to the nanostars, which resulted in red shifts as large as 51 nm and a limit of detection as low as 0.

Direct glucose sensing in the physiological range through plasmonic nanoparticle formation.

Development of improved glucose detection has vast significance in both clinical and point of care settings. Herein, we present a novel, label-free, enzyme-free, colorimetric method of glucose detection that relies on the reduction of a gold salt precursor facilitated by physiological concentrations of glucose (1.25-50 mM).

High Raman enhancing shape-tunable ag nanoplates in alumina: a reliable and efficient SERS technique.

Shape-tunable Ag nanoplates in alumina enable very strong SERS performances showing Raman enhancement factor >1 × 10(9), and allows for easy detection of analyte methylene blue having a concentration in the picomolar range. Raman enhancements have been systematically studied during the Ag nanoparticle-shape evolution from spherical nanoparticles to hexagonal nanoplates with sharp corners to truncated triangular nanoplates in alumina sol. Large SERS enhancement has been observed because of the uniform dispersion and embedment of Ag nanoplates in a relatively high dielectric alumina network where analyte molecules are held.

A facile synthesis of cubic (Im3m) alumina films on glass with potential catalytic activity.

Thermally stable phase pure mesoporous cubic (Im3m) alumina films were synthesized on glass substrates under ambient conditions. These cubic alumina films incorporated with Au NPs exhibited excellent catalytic property.

Anisotropic gold nanoparticle doped mesoporous boehmite films and their use as reusable catalysts in electron transfer reactions.

Anisotropic Au nanoparticle (NP) doped mesoporous and oriented boehmite films of about 2 microm in thickness were prepared and used as reusable catalysts. The films were characterized by grazing incidence X-ray diffraction (GIXRD), field emission scanning electron and transmission electron microscopies, optical absorptions and surface area and pore size measurements. GIXRD of the doped films showed a preferential growth of boehmite crystallites in the (020) plane.

Synthesis of thick mesoporous gamma-alumina films, loading of Pt nanoparticles, and use of the composite film as a reusable catalyst.

Nanocrystalline mesoporous gamma-Al2O3 film of high thickness has been developed and characterized. The films were prepared on ordinary glass substrates by a single dip-coating method using boehmite (AlOOH) sols derived from aluminum tri-sec-butoxide in presence of cetyltrimethylammonium bromide (CTAB) as structure-directing agent. The dried films were heat-treated at 500 degrees C in air to remove the organics and strengthen the network.