Layered lead bismuth selenide, PbBi2Se4, an intergrowth compound of PbSe (rocksalt) and Bi2Se3 (hexagonal), is a topological insulator in the bulk phase. We present a simple solution based synthesis of two dimensional (2D) few seven atomic (septuple) layered PbBi2Se4 nanosheets (4-7 nm thick) for the first time. The excellent electrical transport in ultrathin PbBi2Se4 is attributed to the prese...

Nanoporous architecture has long been predicted theoretically for its proficiency in suppressing thermal conduction, but less concerned as a practical approach for better thermoelectric materials hitherto probably due to its technical challenges. This article demonstrates a study on nanoporous PbSe-SiO2 composites fabricated by a facile method of mechanical alloying assisted by subsequent wet-m...

We demonstrate a novel approach for the large-scale, shape-controlled synthesis of one-dimensional (1D) corrugated nanoarrays of Pb(1-x)Mn(x)Se nanocrystals (0.002 < or = x < or = 0.008) through an in-situ self-assembly without using either capping polymer or ionic surfactant. The one-step-prepared 1D nanoarrays exhibit a well-defined morphology, single-crystal orientation, and clean surface wi...

Inert metal-selenide colloids are found in animals. They are believed to afford cross-protection against the toxicities of both metals and selenocompounds. Here, the toxicities of metal salt and sodium selenide mixtures were systematically studied using the death rate of Saccharomyces cerevisiae cells as an indicator. In parallel, the abilities of these mixtures to produce colloids were assesse...

It has been shown that in hybrid polymer-inorganic photovoltaic devices not all the photogenerated excitons dissociate at the interface immediately, but can instead exist temporarily as bound charge pairs (BCPs). Many of these BCPs do not contribute to the photocurrent, as their long lifetime as a bound species promotes various charge carrier recombination channels. Fast and efficient dissociat...

Semiconductor nanocrystals are promising for use in cheap and highly efficient solar cells. A high efficiency can be achieved by carrier multiplication (CM), which yields multiple electron-hole pairs for a single absorbed photon. Lead chalcogenide nanocrystals are of specific interest, since their band gap can be tuned to be optimal to exploit CM in solar cells. Interestingly, for a given photo...

We report ripening of metal particles anchored on pyramid-shaped heterostructure nanocrystals. The 'intra-particle' ripening results in a large metal tip at one corner with the other three tips vanishing. Investigation reveals that the ripening and core/shell formation affects photocatalytic activities via the Fermi level change.

Lead-based (IV-VI) colloidal quantum dots (QDs) are of widespread scientific and technological interest owing to their size-tunable band-gap energy in the near-infrared optical region. This article reviews the synthesis of PbSe-based heterostructures and their structural and optical investigations at various temperatures. The review focuses on the structures consisting of a PbSe core coated wit...