The in situ synthesis of PbS nanocrystals from lead(II) n-octylxanthate within a 1,3-diisopropenylbenzene-bisphenol A dimethacrylate sulfur copolymer.

The synthesis of lead sulfide nanocrystals within a solution processable sulfur 'inverse vulcanization' polymer thin film matrix was achieved from the in situ thermal decomposition of lead(II) n-octylxanthate, [Pb(S2COOct)2]. The growth of nanocrystals within polymer thin films from single-source precursors offers a faster route to networks of nanocrystals within polymers when compared with ex situ routes. The 'inverse vulcanization' sulfur polymer described herein contains a hybrid linker system which demonstrates high solubility in organic solvents, allowing solution processing of the sulfur-based polymer, ideal for the formation of thin films. The process of nanocrystal synthesis within sulfur films was optimized by observing nanocrystal formation by X-ray photoelectron spectroscopy and X-ray diffraction. Examination of the film morphology by scanning electron microscopy showed that beyond a certain precursor concentration the nanocrystals formed were not only within the film but also on the surface suggesting a loading limit within the polymer. We envisage this material could be used as the basis of a new generation of materials where solution processed sulfur polymers act as an alternative to traditional polymers.

High magnetic relaxivity in a fluorescent CdSe/CdS/ZnS quantum dot functionalized with MRI contrast molecules.

Light emitting semiconducting quantum dots show great promise as solar cells, optoelectronic devices and multimodal imaging probes. Here we demonstrate successful grafting of a thiol-functionalised GdIII MRI contrast agent onto the surface of core-multishell CdSe/CdS/ZnS quantum dots. The resulting nanoprobe exhibits intense photoluminescence and unprecedentedly large T1 relaxivity of 6800 mM-1 s-1 per nanoparticle due to secure implanting of ca. 620 magnetic centers per quantum dot unit.

Precursor determined lateral size control of monolayer MoS2 nanosheets from a series of alkylammonium thiomolybdates: a reversal of trend between growth media.

The growth of ligand-free MoS2 nanosheets with mean lateral sizes below 5 nm at 270 °C is reported. Nanosheets grown from a melt of tetraalkylammonium tetrathiomolybdates, [R4N]2[MoS4] (R = n-butyl, n-hexyl or n-octyl) vary in width between mean lateral sizes of 4.35 and 2.1 nm. Inclusion of the precursors into a polymer matrix shows the opposite trend in lateral dimensions with sheet widths ranging from 3.5 to 4.8 nm.