Colloidal quantum dot solar cells (CQDSCs) are attracting growing attention owing to significant improvements in efficiency. However, even the best depleted-heterojunction CQDSCs currently display open-circuit voltages (VOCs) at least 0.5 V below the voltage corresponding to the bandgap. We find that the tail of states in the conduction band of the metal oxide layer can limit the achievable dev...

The influence of quantum confinement on the one- and two-photon absorption spectra (1PA and 2PA) of PbS and PbSe semiconductor quantum dots (QDs) is investigated. The results show 2PA peaks at energies where only 1PA transitions are predicted and 1PA peaks where only 2PA transitions are predicted by the often used isotropic k x p four-band envelope function formalism. The first experimentally i...

Nanoparticles often self-assemble into hexagonal-close-packed (hcp) structures although it is predicted to be less stable than face-centered-cubic (fcc) packing in hard-sphere models. In addition to close-packed fcc and hcp superlattices, we observe formation of nonclose-packed simple-hexagonal (sh) superlattices of nearly spherical PbS, PbSe, and gamma-Fe2O3 nanocrystals. This surprisingly ric...

Oriented attachment of PbSe nanocubes can result in the formation of two-dimensional (2D) superstructures with long-range nanoscale and atomic order. This questions the applicability of classic models in which the superlattice grows by first forming a nucleus, followed by sequential irreversible attachment of nanocrystals, as one misaligned attachment would disrupt the 2D order beyond repair. H...

Background and Aims: Mercury, with its oxidative activity, causes damage to the antioxidant enzymes thus resulting in physiological disorders. Sodium selenide is an antioxidant that protects antioxidant enzymes. The aim of this study was to investigate the protective effect of sodium selenide on renal toxicity induced by mercuric chloride in rats. Materials and Methods: Animals were divided in...

Well-defined crystalline PbSe nanocubes and nanospheres have been synthesized through a simple hydrothermal method by using Pb2+- EDTA and Pb2+- oleylamine complexes at 180°C for different reaction times. Composition and morphology of the samples have been characterized by means of XRD and SEM. Gradual release process of Pb2+ from Pb2+-EDTA and Pb2+-oleylamine complexes can adjust the growth ra...

One-dimensional (1D) assemblies of semiconductor nanocrystals (NCs) represent an important kind of 1D nanomaterial system due to their potential for exploring novel and enhanced electronic and photonic performances of devices. Herein, we present mass fabrication of a series of 1D arrays of CdSe and PbSe NCs on a large length scale with ultralong, aligned Se nanowires (NWs) as both the reactant ...

A transferable force field for the PbSe-CdSe solid system using the partially charged rigid ion model has been successfully developed and was used to study the cation exchange in PbSe-CdSe heteronanocrystals [A. O. Yalcin et al., "Atomic resolution monitoring of cation exchange in CdSe-PbSe heteronanocrystals during epitaxial solid-solid-vapor growth," Nano Lett. 14, 3661-3667 (2014)]. In this ...

An enzyme preparation from Salmonella typhimurium catalyzes the conversion of 5-methylaminomethyl-2-thiouridine in tRNAs to 5-methylaminomethyl-2-selenouridine when supplemented with selenide and ATP. Similar preparations from a Salmonella mutant strain carrying a defective selD gene fail to catalyze this selenium substitution reaction. However, supplementation of the deficient enzyme preparati...