Controlled covalent modification of epitaxial single layer graphene on 6H-SiC (0001) with aryliodonium salts using electrochemical methods.

Controlled covalent modification of graphene via electrochemically assisted grafting of molecules is expected to be a robust method for tuning the doping levels and work function and therefore enabling the deployment of graphene in photovoltaic and battery applications. By using aryliodonium salts, in particular, bis(4-nitrophenyl)iodonium tetrafluoroborate, the grafting density can be adjusted from 4 × 10(13) to 3 × 10(14) molecules per cm(2). New insights on the grafting mechanism and the reactivity of the graphene are reported here.

Room-temperature epitaxial electrodeposition of single-crystalline germanium nanowires at the wafer scale from an aqueous solution.

Direct epitaxial growth of single-crystalline germanium (Ge) nanowires at room temperature has been performed through an electrodeposition process on conductive wafers immersed in an aqueous bath. The crystal growth is based on an electrochemical liquid-liquid-solid (ec-LLS) process involving the electroreduction of dissolved GeO2(aq) in water at isolated liquid gallium (Ga) nanodroplet electrodes resting on single-crystalline Ge or Si supports. Ge nanowires were electrodeposited on the wafer scale (>10 cm(2)) using only common glassware and a digital potentiostat.

Electrical property heterogeneity at transparent conductive oxide/organic semiconductor interfaces: mapping contact ohmicity using conducting-tip atomic force microscopy.

We demonstrate mapping of electrical properties of heterojunctions of a molecular semiconductor (copper phthalocyanine, CuPc) and a transparent conducting oxide (indium-tin oxide, ITO), on 20-500 nm length scales, using a conductive-probe atomic force microscopy technique, scanning current spectroscopy (SCS). SCS maps are generated for CuPc/ITO heterojunctions as a function of ITO activation procedures and modification with variable chain length alkyl-phosphonic acids (PAs). We correlate differences in small length scale electrical properties with the performance of organic photovoltaic cells (OPVs) based on CuPc/C(60) heterojunctions, built on these same ITO substrates.

Performance evaluation of a constructed wetland treating high-ammonium primary domestic wastewater effluent.

An investigation of a top-loading, vertical-flow, submerged-bed constructed wetland system subject to a New York State discharge permit, of mineral nitrogen transformations occurring within the wetland units, and of the effects of local environment on system performance indicated 100% removal of biochemical oxygen demand (BOD) and mean 99.0 +/- 1.1% removal of ammonium (NH4(+)).

A planar, chip-based, dual-beam refractometer using an integrated organic light-emitting diode (OLED) light source and organic photovoltaic (OPV) detectors.

We present a simple chip-based refractometer with a central organic light-emitting diode (OLED) light source and two opposed organic photovoltaic (OPV) detectors on an internal reflection element (IRE) substrate, creating a true dual-beam sensor platform. For first-generation platforms, we demonstrate the use of a single heterojunction OLED based on electroluminescence from an Alq(3)/TPD heterojunction (tris-(8-hydroxyquinoline)aluminum/N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine) and light detection with planar heterojunction pentacene/C(60) OPVs. The sensor utilizes the considerable fraction of emitted light from conventional thin-film OLEDs that is coupled into guided modes in the IRE, instead of into the forward (display) direction.