An investigation of the optical and magnetic properties of a unique hydrogen-linked conjugate nanostructure, comprised of superparamagnetic gamma-Fe(2)O(3) nanoparticles (NPs) and near-infrared PbSe nanocrystal quantum dot (NQD) chromophores, is reported. The results show retention of the NQDs' emission quantum efficiency and radiative lifetime, and only a small red shift of its band energy, up...

MoSe2 nanosheets have been extensively pursued due to the outstanding properties of this typical layered transition metal dichalcogenide (LTMD). In this work, we report a facile, fast strategy to synthesize scalable hierarchical ultrathin MoSe2-x (x ∼ 0.47) nanosheets. The nanosheets possess 2-5 Se-Mo-Se atomic layers and were synthesised through a bottom-up colloidal route within 20 mins under...

We report a novel synthesis of porous PbSe layers on Si substrates using anodic electrochemical treatment of PbSe/CaF2/Si(111) epitaxial structures in an electrolyte solution based on glacial acetic acid and nitric acid. Electron microscopy, x-ray diffractometry, and local chemical microanalysis investigations results for the porous layers are presented. Average size of the synthesized mesopore...

We report for the first time on rich and tunable transport phenomena in closed-packed arrays of PbSe colloidal nanocrystals (NCs) in the form of thin films. As the interdot coupling is increased, the system evolves from an insulating regime dominated by Coulomb blockade to a semiconducting regime, where hopping conduction is the dominant transport mechanism. The observed phenomena can be interp...

First principles electronic structure calculations based on a plane wave expansion of the wavefunctions are the most commonly used approach for electronic structure calculations in materials and nanoscience. In this approach the electronic wavefunctions are expanded in Fourier components and 3D FFTs are used to construct the charge density in real space. Efficient parallel 3D FFTs are required ...

We report the synthesis of amorphous (PbSe)100-xCdx (x = 5, 10, 15, and 20) nanoparticle thin films using thermal evaporation method under argon gas atmosphere. Thin films with a thickness of 20 nm have been deposited on glass substrates at room temperature under a continuous flow (50 sccm) of argon. X-ray diffraction patterns suggest the amorphous nature of these thin films. From the field emi...

Bulk nanostructured materials are made from the assembly of octahedral PbSe nanocrystals. After thermal annealing, the artificial bulk demonstrates a large difference in behavior depending on the temperature, and a large variation of room-temperature resistivity of up to seven orders of magnitude. This variation originates from the high-indexed sharp edges of the octahedral nanocrystals. As the...

Quantum dots form equilibrium structures in liquid dispersions, due to thermodynamic forces that are often hard to quantify. Analysis of these structures, visualized using cryogenic electron microscopy, yields their formation free energy. Here we show that the nanoparticle interaction free energy can be further separated into the enthalpic and entropic contributions, using the temperature depen...

Nanorod solar cells have been attracting a lot of attention recently, as they have been shown to exhibit a lower carrier multiplication onset and a higher quantum efficiency than quantum dots with similar bandgaps. The underpinning theory for this phenomenon is not yet completely understood, and is still the subject of ongoing study. Here we conduct a theoretical investigation into CM efficienc...

PbSe nanotubes were successfully synthesized by a reactive template approach via solvothermal transformation of trigonal selenium (t-Se) nanotubes in ethylene glycol. It was revealed that a relatively high reaction temperature (e.g., 200 degrees C), adequate ascorbic acid, and proper lead source were crucial for preparing PbSe nanotubes through shape-preserved transformation of t-Se nanotubes. ...