Wepresent a detailed experimental and theoretical Raman investigation of quantum confinement and laser-induced local thermal effects on hydrogenated nanocrystalline silicon with different nanocrystal sizes (3.6–6.2nm). The local temperature was monitored by measuring the Stokes/anti-Stokes peak ratio with the laser power density range from ~120 to 960kW/cm. In combination with the three-dimensi...

Single nanocrystal arrays were fabricated on sub-microwells of poly(ethylene glycol) (PEG) copolymer using selective wetting on the hydrophilic regions of the exposed substrate surface and subsequent drying. Templates were produced by molding a thin film of a PEG-based random copolymer on hydrophilic substrates such as glass or silicon dioxide. The polymeric microstructures provide a topographi...

Self-assembling of nanocrystals involves organization of nanocrystals encapsulated by protective compact organic molecules into a crystalline material. The adsorbed molecules not only serve as the protection layer for the nanocrystals but also provide the dominant cohesive interactions (or “bonding”) sustaining the nanocrystal superlattices. The length of the adsorbed molecules is a controllabl...

Incorporation of doping ions in nanocrystals is a strategy for providing nanophases with functions directly related to ion features. At the nanoscale, however, doping can also activate more complex effects mediated by perturbation of the nanophase size and structure. Here, we report a paradigmatic case in which we modify grown-in-glass γ-Ga2 O3 nanophases by nickel or titanium doping of the sta...

Silicon nanocrystals were formed in SiO2 using Si ion implantation followed by thermal annealing. The nanocrystal-doped SiO2 layer was implanted with Er to a peak concentration of 1.8 at. %. Upon 458 nm excitation the sample shows a broad nanocrystal-related luminescence spectrum centered around 750 nm and two sharp Er luminescence lines at 982 and 1536 nm. By measuring the excitation spectra o...

Figure 1: [A] Scattering intensity as a function of scattering angle for the 20 base-pair double-labeled (blue), single-labeled (red, magenta; indistinguishable), and unlabeled (cyan) DNA duplexes. The intensity of the double-labeled sample has been scaled by a factor of 1/2 to aid visual comparison. The pattern of scattering interference between the two nanocrystal labels (black) is obtained b...

Membrane osmometry is used to measure osmotic pressures of dilute solutions containing quasi-spherical CdSe nanocrystals covered with polymer brushes in toluene in the range 31 to 45°C. Osmotic-pressure data, as a function of nanocrystal concentration, yield the molecular weight and the osmotic second virial coefficient of the nanocrystals; the latter is related to the potential of mean force b...

Supported catalysts are widely used in industry and can be optimized by tuning the composition and interface of the metal nanoparticles and oxide supports. Rational design of metal-metal oxide interfaces in nanostructured catalysts is critical to achieve better reaction activities and selectivities. We introduce here a new class of nanocrystal tandem catalysts that have multiple metal-metal oxi...

We report on the correlation between the nanocrystal and surface alloy properties with the bimetallic composition of gold-platinum(AuPt) nanoparticles. The fundamental understanding of whether the AuPt nanocrystal core is alloyed or phasesegregated and how the surface binding properties are correlated with the nanoscale bimetallic properties is important not only for the exploitation of catalyt...

We present the first semiconductor nanocrystal films of nanoscale dimensions that are electrically conductive and crack-free. These films make it possible to study the electrical properties intrinsic to the nanocrystals unimpeded by defects such as cracking and clustering that typically exist in larger-scale films. We find that the electrical conductivity of the nanoscale films is 180 times hig...