Two-dimensional films of semiconductors can be patterned into super-lattices with nanoscale periodicity, using top-down (lithography) or bottom-up approaches. In particular, square and honeycomb lattices of semiconductor nanocrystals have been recently synthesized using oriented attachment. We have performed atomistic tight-binding calculations of the conduction bands of super-lattices of CdSe....

A method of synthesizing and controlling the size of germanium nanocrystals is developed. A tri-layer metalinsulator-semiconductor (MIS) memory device structure comprising of a thin (~5nm) silicon dioxide (SiO2) layer grown using rapid thermal oxidation (RTO), followed by a layer of Ge+SiO2 of varying thickness (3 6 nm) deposited using a radio frequency (rf) co-sputtering technique, and a cappi...

We report on PbS colloidal nanocrystals that combine within one structure solubility in physiological solvents with near-infrared photoluminescence, and magnetic and optical properties tuneable by the controlled incorporation of magnetic impurities (Mn). We use high magnetic fields (B up to 30 T) to measure the magnetization of the nanocrystals in liquid and the strength of the sp-d exchange in...

This Perspective outlines basic structural and optical properties of lead halide perovskite colloidal nanocrystals, highlighting differences and similarities between them and conventional II-VI and III-V semiconductor quantum dots. A detailed insight into two important issues inherent to lead halide perovskite nanocrystals then follows, namely, the advantages of defect tolerance and the necessi...

Methods for introducing new magnetic, optical, electronic, photophysical, or photochemical properties to semiconductor nanocrystals are attracting intense applications-oriented interest. In this communication, we report the preparation and electronic absorption spectroscopy of colloidal ZnO DMS-QDs. Our synthetic procedure involves modification of literature methods known to yield highly crysta...

Understanding the pathways of hot exciton relaxation in photoexcited semiconductor nanocrystals, also called quantum dots (QDs), is of paramount importance in multiple energy, electronics and biological applications. An important nonradiative relaxation channel originates from the nonadiabatic (NA) coupling of electronic degrees of freedom to nuclear vibrations, which in QDs depend on the confi...

The paper reviews recent progress on chiral nanocrystal assemblies with induced optical chirality and related circular dichroism. Many natural molecules and biomolecules are chiral and exhibit remarkably strong optical chirality (circular dichroism) due to their amazingly uniform atomic composition in a large ensemble. It is challenging to realize artificial nanoscale systems with optical chira...

Nanocrystals prepared in organic media can be easily self-assembled into close-packed hexagonal monolayers on solvent evaporation for various applications. However, they usually rely on the use of organometallic precursors that are soluble in organic solvents. Herein we report a general protocol to transfer metal ions from an aqueous solution to an organic medium, which involves mixing the aque...

Thin films comprising semiconductor nanocrystals are emerging for applications in electronic and optoelectronic devices including light emitting diodes and solar cells. Achieving high charge carrier mobility in these films requires the identification and elimination of electronic traps on the nanocrystal surfaces. Herein, we show that in films comprising ZnO nanocrystals, an electron acceptor t...

The capacity of fluorescent colloidal semiconductor nanocrystals for commercial application has led to the development of nanocrystals with nontoxic constituent elements as replacements for the currently available Cd- and Pb-containing systems. CuInS2 is a good candidate material because of its direct band gap in the near-infrared spectral region and large optical absorption coefficient. The te...