Recombinant Enterovirus B Coxsackievirus B3 [GST]

Two-dimensional (2D) chalcogen-based layers have proven to be the next generation of materials for potential high-tech applications, and it is very important to control their properties at the nanoscale. Herein, we discuss the structural and electronic properties of Au(111) surface after being exposed to high temperature vapor deposition of Tellurium (Te) in ultrahigh vacuum. The scenarios entailing the formation of 2D AuTe2 metal dichalcogenide or rather Au-Te alloy monolayer (ML) or even Tellurene single layer deserved to be addressed. In this purpose, low energy electron diffraction (LEED) supported by scanning tunneling microscopy (STM) shows the existence of several surface reconstructions depending on the Te film thickness in the sub-monolayer regime. We observed that the well-known spin-split Shockley state of the Au(111) surface survives the Te deposition and is even shifted to higher binding energy, suggesting a charge transfer at the interface. For a coverage of 0.33 ML of Te, new dispersive bands are observed by angle-resolved photoemission (ARPES), which arise from a strong hybridization between the electronic states of Te and Au. With a substantially low intensity and a back-folding at the boundaries of the reduced surface Brillouin zone (R-SBZ), these electronic bands represent a proof of the existence of a naturel 2D electron gas, strongly disturbed by the surface reconstruction. It is therefore possible that an Au-Te alloy is formed at the surface. By increasing the coverage to 0.5 ML, a rich, thickness-dependent transition develops from the surface alloy to Tellurene-like structure and completely excludes the growth of AuTe2 monolayer. Both the surface alloy and the Tellurene monolayer have a semiconductor character with a gap in the occupied states of about 0.65 eV.

We report a detailed investigation of a series of new charge-transfer (CT) complexes assembled via a two-point complementary hydrogen bonding (H-bonding) of diindolopyrrole (DIP) electron donors with o-quinone and diazafluorenone acceptors. Unidirectional polarization through the DDMIDLINE HORIZONTAL ELLIPSISAA type H-bonding leads to a dramatic perturbation of electronic levels of the donor and the acceptor. pi-Stacking of the H-bonded pairs results in strong charge-transfer (HOMO-LUMO) interactions in their ground state, manifested in low energy optical absorption. Density functional theory (DFT) calculations predict a H-bonding induced rise of the HOMOD (by up to 0.5 eV) and lowering of the LUMOA (by up to 0.7 eV). As a result, the complexes of relatively weak electron donors and acceptor ability exhibit remarkably low optical energy gaps (down to <0.8 eV), that can be tuned by varying the ionization potential and electron affinity of the individual components. Single crystal X-ray analysis for 6 complexes displayed H-bond lengths between 1.9 and 2.3 angstrom and short pi-stacking distances (>= 3.2 angstrom), in line with strong donor-acceptor interactions. Thin-film transistors of such a H-bonded complex, fabricated by vacuum co-sublimation of PhDIP and pyrenetetraone, showed ambipolar charge transport with unusual 'double dip' characteristics.