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Phosphotungstic acid (PTA) (a polyoxometalate) is immobilized on the surface of boron-doped diamond (BDD) surface through electrostatic self-assembly of PTA on pyridinium dye-functionalized-BDD. The studies have shown the utility of PTA as a molecular switch in which the direction of photocurrent from diamond to methyl viologen is reversed by the surface bound PTA.

An all electrochemical route to functionalized graphene directly from a graphite electrode is described herein obviating the need for defect inducing oxidative or prolonged sonication treatments. Enhanced electrochemical expansion of graphite is achieved by sequential treatment beginning with the established method of expansion by electrolysis in a Li+ containing electrolyte and then with the much larger tetra-n-butylammonium. The result is a hyperexpansion of the graphite basal planes. As a demonstration of the utility of this method we successfully performed a subsequent in situ electrochemical diazonium functionalization of the hyperexpanded graphite basal planes to give functional graphene sheets. This potential controlled process is more effective than chemical processes and also provides a means of controlling the degree of functionalization. We have further demonstrated that the functionalized graphene could be converted to a pristine low defect form via laser ablation of the functional groups. As a result this method presents a potentially scalable approach for graphene circuit patterning. [ABSTRACT FROM AUTHOR]

Efficient chemical functionalization of hydrogen-terminated Si(111) with simple and bifunctional 1-alkenes was achieved via novel sonochemical activated hydrosilylation, utilizing just a simple ultrasonic bath. It is an extremely mild method that allows the specific attachment of unprotected bifunctional alkenes such as undecenol, undecylenic acid, and even a heat/UV-sensitive alkene, bearing an activated leaving group (N-succinimidyl Undecylenate), without suffering any degradation. [ABSTRACT FROM AUTHOR]

Direct UV photochemical functionalization of H-terminated Si(111) with bifunctional 10-undecen-1-ol was achieved with selective attachment via its vinyl end, resulting in the formation of a compact monolayer with free terminal alcohol groups. This is due to the faster radical propagation mechanism in hydrosilylation with alkene compared to the nucleophilic attack mechanism of alcohol, which is impeded by intermolecular hydrogen bonding present at room temperature. Evidence from X-ray photoelectron spectroscopy, infrared spectroscopy, and resistance to fluoride etching shows that Si−C is the interfacial bond, and atomic force microscopy shows the presence of a smooth, uniform monolayer conforming to the atomic terraces of the Si(111) surface. The application of such a hydroxyl-terminated monolayer was demonstrated by tethering a bromoinitiator through surface esterification and thereafter subjecting the surface to the surface-initiated atom-transfer radical polymerization of butyl methacrylate. The poly(butyl methacrylate) brushes formed were found to be smooth (Ra< 0.3 nm) and uniform even for a thin film of 4.0 nm. [ABSTRACT FROM AUTHOR]

We demonstrate a facile method for the Suzuki coupling of aryl molecules on the diamond surface. This is a more versatile alternative compared to previous coupling methods based on alkene linkers because it opens up possibilities for the application of diamond in molecular electronics and photovoltaics. The diamond surface is premodified with aryldiazonium salt in order to functionalize it with aryl halide or aryl boronic acid, and these are then used as synthons in the subsequent Suzuki coupling to aryl molecules. This method is highly specific and can be used for the uninterrupted molecular conjugation of diamond to a large class of organic molecules. As a proof of concept, we also demonstrate a diamond−fullerene photocurrent converter by using Suzuki coupled oligothiophene as the conjugated linker between diamond (electron donor) and fullerene (electron acceptor). [ABSTRACT FROM AUTHOR]

The optimization of biosensing efficiency on a diamond platform depends on the successful coupling of biomolecules on the surface, and also on effective signal transduction in the biorecognition events. In terms of biofunctionalization of diamond surfaces, surface electrochemical studies of diamond modified with undecylenic acid (UA), with and without headgroup protection, were performed. The direct photochemical coupling method employing UA was found to impart a higher density of carboxylic acid groups on the diamond surface compared to that using trifluoroethyl undecenoate (TFEU) as the protecting group during the coupling process. Non-faradic impedimetric DNA sensing revealed that lightly doped diamond gives better signal transduction sensitivity compared to highly doped diamond. [ABSTRACT FROM AUTHOR]

The article provides information on photochemistry as a field of study for diamond-based molecular platforms. It states that diamond electronic devices can give better performance in power diodes and transistors with high-frequency field effects due to its intrinsic greater carrier mobilities and broad band gap. It also mentions that boron-doped diamond thin films showed higher photoconversion ratio and photostability than tin-doped indium oxide and fluoride-doped tin oxide.