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Articles you may be interested inAdsorption and thermal decomposition of acetic acid on Si ( 111 ) 7 × 7 studied by vibrational electron energy loss spectroscopy J. Chem. Phys. 132, 174702 (2010) Pyrrole adsorption on Si(111)-(7ϫ7) has been investigated using high-resolution electron energy loss spectroscopy ͑HREELS͒, thermal desorption spectroscopy, scanning tunneling microscopy ͑STM͒, and theoretical calculations. Compared to physisorbed pyrrole, chemisorption leads to the appearance of N-Si and Si-H vibrational features, together with the absence of N-H stretching mode. This clearly demonstrates the dissociative nature of pyrrole chemically binding on Si(111)-(7ϫ7) through the breakage of N-H bond. Based on STM results, the resulting fragments of pyrrolyl and H atom are proposed to bind with an adatom and an adjacent rest atom, respectively. The STM images further reveal that the adsorption is site selective. The faulted center adatoms are most favored, followed by unfaulted center adatoms, faulted corner adatoms, and unfaulted corner adatoms. In addition, the chainlike pattern of reacted adatoms was observed, implying the possible existence of attractive interaction between adsorbed pyrrolyl and the precursor state. Theoretical calculation confirms that the dissociative adsorption with pyrrolyl bonded to an adatom and H atom to an adjacent rest atom is energetically favored compared to the associative cycloaddition involving the two ␣-carbon atoms of pyrrole and an adatom-rest atom pair.

Using the elastic-scattering quantum chemistry technique, it is shown that a surface atomic wire fabricated by extracting a line of S surface atoms from the planar MoS(2) lamellar substrate creates enough electronic states in the MoS(2) surface band gap for this wire to have a large conductance. The nature of the surface electronic states introduced by the S vacancies is investigated for increasing numbers of vacancies for a wire length of up to 10 nm. When contacted by the two Au nanoelectrodes, the wire creates surface pseudoballistic channels and the wire conductance does not decrease with length. The effects of the nanoelectrode-wire distance and of the lateral electrode-wire overlap on the conductance of the wire are also discussed. It is found that the conductance of the junction can be increased threefold by increasing the lateral overlap

Zinc phthalocyanine (ZnPc): fullerene-C60 (C60)-based organic photovoltaic (OPV) with high power conversion efficiency (PCE) are fabricated. Homogeneously distributed grains of ∼40–50 nm are observed for the ZnPc:C60 blend layer deposited on bare indium-tin oxide (ITO) substrates. In contrast, the blend layer form grains of smaller lateral extensions (∼20–30 nm) on 3, 4-polyethylenedioxythiophene: polystyrenesulfonate modified ITO substrates. OPV fabricated on the former substrates show PCE of up to 3.9% that is about twice the PCE (1.9%) obtained for the devices on the latter substrates. This effect can be explained by better transport properties and reduced charge recombination of the blend layer on the bare ITO.