Supercapacitor Electrodes from the in Situ Reaction between Two-Dimensional Sheets of Black Phosphorus and Graphene Oxide

Two-dimensional materials show considerable promise as high surface area electrodes for energy-storage applications such as supercapacitors. A single sheet of graphene possesses a large specific surface area because of its atomically thin thickness. However, to package this area efficiently in a device, it must be confined within a finite three-dimensional volume without restacking of the sheet faces. Herein, we present a method of maintaining the high surface area through the use of a hybrid thin film in which few-layer-exfoliated black phosphorus (BP) reduces graphene oxide (GO) flakes. When the film is exposed to moisture, a redox reaction between the BP and the GO forms an interpenetrating network of reduced GO (RGO) and a liquid electrolyte of intermediate phosphorus acids H_<i>x</i>PO_<i>y</i>. The presence of the liquid H_<i>x</i>PO_<i>y</i> electrolyte in the RGO/H_<i>x</i>PO_<i>y</i> film stabilizes and preserves an open-channel structure enabling rapid ion diffusion, leading to an excellent charging rate capability (up to 500 mV s^–1 and retaining 62.3% of initial capacitance at a large current density of 50 A g^–1) when used as electrodes in supercapacitors

In Situ Synthesis of PbS Nanocrystals in Polymer Thin Films from Lead(II) Xanthate and Dithiocarbamate Complexes: Evidence for Size and Morphology Control

Lead sulfide has been grown from single molecular precursors within a polymer matrix to form networks of PbS nanocrystals. These materials are model systems for the processing of polymer–nanoparticle layers for flexible hybrid photovoltaic devices. Processing is achieved by spin coating a solution containing the precursor and polymer onto a substrate, followed by heating of the film to decompose the precursor. The effect of precursor chemistry has been explored using lead­(II) dithiocarbamates, their 1,10-phen adducts, and lead­(II) xanthates with different alkyl chain lengths (butyl, hexyl, and octyl). The xanthates were found to be more promising precursors giving control over nanocrystal size and shape on variation of the alkyl chain length. The lead­(II) octyl xanthate complex causes anisotropic growth, forming PbS nanowires within the polymer matrix