이도창

Colloidal FePt nanocrystals, 6 nm in diameter, were synthesized and then coated with silica (SiO2) shells. The silica shell thickness could be varied from 10 to 25 nm. As-made FePt@SiO2 nanocrystals have low magnetocrystalline anisotropy due to a compositionally disordered FePt core. When films of FePt@SiO2 particles are annealed under hydrogen at 650 degrees C or above, the FePt core transforms to the compositionally ordered L1(0) phase, and superparamagnetic blocking temperatures exceeding roo

In this study, we synthesized Ge nanocrystals and studied the effects of variables such as solvents, reducing agents, reaction temperature, and capping ligands. The resulting nanocrystals showed infrared photoluminescence with quantum yields as high as approximately 8% and enhanced resistance to oxidation. Size analysis of the samples by transmission electron microscopy revealed that the size dependence of the emission is consistent with the effects of quantum confinement.

Multiwall carbon nanotubes (MWNTs) were synthesized in supercritical toluene at 600 degrees C and approximately 12.4 MPa using ferrocene, Fe, or FePt nanocrystals as growth catalysts. Toluene serves as both the carbon source for nanotube formation and the solvent. In contrast to vapor-phase synthetic routes, the supercritical solvent provides high precursor concentration and a homogeneous reaction environment with dispersed growth catalyst particles. Both carbon filaments and MWNTs are produced

We report the photocatalytic conversion of CO2 to CH4 using CuPt alloy nanoclusters anchored on TiO2. As the size of CuPt alloy nanoclusters decreases, the photocatalytic activity improves significantly. Small CuPt nanoclusters strongly bind CO2 intermediates and have a stronger interaction with the TiO2 support, which also contributes to an increased CH4 generation rate. The alloying and size effects prove to be the key to efficient CO2 reduction, highlighting a strategic platform for the desig

Under pressure! The synthesis of crystalline silicon nanowires can be carried out in organic solvents at reaction temperatures of up to 450–500°C under high-pressure conditions. Gold particles are used as seeds, and organosilanes are employed as the silicon source. The decomposition chemistry of the organosilanes determines the quality of the nanowires formed (see picture of an Si nanowire with an Si/Au tip).

We present the synthesis of composite PbSe/CdSe/CdS nanocrystals with two distinct geometries: core/shell/shell structures and tetrapods. These novel nanostructures exhibit extremely long carrier decay times up to 20 micros that are combined with high emission efficiencies in the infrared. The increase in carrier lifetimes is attributed to the reduction of the electron-hole overlap as a result of delocalization of the electron wave function into the outer CdS shell or arms. The ultralong carrier

There is an evergrowing demand for environment-friendly processes to synthesize ammonia (NH₃) from atmospheric nitrogen (N₂). Although diazotrophic N₂ fixation represents an undeniably "green" process of NH₃ synthesis, the slow reaction rate makes it less suitable for industrially meaningful large-scale production. Here, we report the photoinduced N₂ fixation using a hybrid system composed of colloidal quantum dots (QDs) and aerobic N<sub>2<

Synthesis of colloidal nanocrystals (NCs), which are not readily available via the wet-chemical approach based on arrested precipitation, has often relied on templated growth. Cation exchange, in which guest cations in bulk solution replace host cations in template NCs, has evolved as one of the most powerful examples. Despite its versatility and facileness, there are caveats because most of the cation-exchange processes presuppose the formation of crystalline defects, which are more or less unc