Understanding of colloidal nanocrystal growth mechanisms is essential for the syntheses of nanocrystals with desired physical properties. The classical model for the growth of monodisperse nanocrystals assumes a discrete nucleation stage followed by growth via monomer attachment, but has overlooked particle-particle interactions. Recent studies have suggested that interactions between particles...

Large-scale microparticle arrays (LSMAs) are key for material science and bioengineering applications. However, previous approaches suffer from trade-offs between scalability, precision, specificity and versatility. Here, we present a porous microwell-based approach to create large-scale microparticle arrays with complex motifs. Microparticles are guided to and pushed into microwells by fluid f...

We demonstrate an analytical method to optimize the stoichiometry and thickness of multilayer silicon oxide films in order to achieve the highest density of non-touching and closely spaced silicon nanocrystals after annealing. The probability of a nanocrystal nearest-neighbor distance within a limited range is calculated using the stoichiometry of the as-deposited film and the crystallinity of ...

The spectral linewidth of an ensemble of fluorescent emitters is dictated by the combination of single-emitter linewidths and sample inhomogeneity. For semiconductor nanocrystals, efforts to tune ensemble linewidths for optical applications have focused primarily on eliminating sample inhomogeneities, because conventional single-molecule methods cannot reliably build accurate ensemble-level sta...

The development of optical gain in chemically synthesized semiconductor nanoparticles (nanocrystal quantum dots) has been intensely studied as the first step toward nanocrystal quantum dot lasers. We examined the competing dynamical processes involved in optical amplification and lasing in nanocrystal quantum dots and found that, despite a highly efficient intrinsic nonradiative Auger recombina...

We use a first-principles based kinetic Monte Carlo simulation to study the movement of a solid iron nanocrystal inside a carbon nanotube driven by the electrical current. The origin of the iron nanocrystal movement is the electromigration force. Even though the iron nanocrystal appears to be moving as a whole, we find that the core atoms of the nanocrystal are completely stationary, and only t...

We examine the effect of strong three-dimensional quantum confinement on the thermopower and electrical conductivity of PbSe nanocrystal superlattices. We show that for comparable carrier concentrations PbSe nanocrystal superlattices exhibit a substantial thermopower enhancement of several hundred microvolts per Kelvin relative to bulk PbSe. We also find that thermopower increases monotonically...

Under the application of electrical currents, metal nanocrystals inside carbon nanotubes can be bodily transported. We examine experimentally and theoretically how an iron nanocrystal can pass through a constriction in the carbon nanotube with a smaller cross-sectional area than the nanocrystal itself. Remarkably, through in situ transmission electron imaging and diffraction, we find that, whil...

Inorganic nanocomposites have been prepared by assembling colloidal nanocrystals and then replacing the organic ligands with precursors to an inorganic matrix phase. Separate synthesis and processing of the nanocrystal and matrix phases allows complete compositional modularity and retention of the superlattice morphologies for sphere (see scheme; top) or rod (bottom) assemblies.