Monitoring volatile organic compounds (VOCs) is an important issue, but difficult to achieve on a large scale and on the field using conventional analytical methods. Electronic noses (eNs), as promising alternatives, are still compromised by their performances due to the fact that most of them rely on a very limited number of sensors and use databases devoid of kinetic information. To narrow the performance gap between human and electronic noses, we developed a novel optoelectronic nose, which features a large sensor microarray that enables multiplexed monitoring of binding events in real-time with a temporal response. For the first time, surface plasmon resonance imaging is demonstrated as a promising novel analytical tool for VOC detection in the gas phase. By combining it with cross-reactive sensor microarrays, the obtained optoelectronic nose shows a remarkably high selectivity, capable of discriminating between homologous VOCs differing by only a single carbon atom. In addition, the optoelectronic nose has good repeatability and stability. Finally, the preliminary assays using VOC binary and ternary mixtures show that it is also very efficient for the analysis of more complex samples, opening up the exciting perspective of applying it to "real-world" samples in diverse domains.

Electrical transport in ultrathin Metal-insulator-semiconductor (MIS) tunnel junctions is analyzed using the temperature dependence of current density and admittance characteristics, as illustrated by Hg//C 12 H 25 -n Si junctions incorporating n-alkyl molecular layers (1.45 nm thick) covalently bonded to Si(111). The voltage partition is obtained from J(V, T) characteristics, over eight decades in current. In the low forward bias regime (0.2-0.4 V) governed by thermionic emission, the observed linear T-dependence of the effective barrier height, qU EFF ðTÞ¼qU B þðkTÞb 0 d T , provides the tunnel barrier attenuation, expðÀb 0 d T Þ, with b 0 ¼ 0.93 Å À1 and the thermionic emission barrier height, U B ¼ 0:53 eV. In the high-forward-bias regime (0.5-2.0 V), the bias dependence of the tunnel barrier transparency, approximated by a modified Simmons model for a rectangular tunnel barrier, provides the tunnel barrier height, U T ¼ 0:5 eV; the fitted prefactor value, G 0 ¼ 10 À10 X À1 , is four decades smaller than the theoretical Simmons prefactor for MIM structures. The density distribution of defects localized at the C 12 H 25 -n Si interface is deduced from admittance data (low-high frequency method) and from a simulation of the response time s R ðVÞ using Gomila's model for a non equilibrium tunnel junction. The low density of electrically active defects near mid-gap (D S < 2  10 11 eV À1 .cm À2 ) indicates a good passivation of dangling bonds at the dodecyl -n Si (111) interface.

Controlling communication: The electronic communication between ferrocenyl centers bound to insulating silicon surfaces can be efficiently controlled; scanning electrochemical microscopy (SECM) shows that both the surface coverage of the electroactive units and the nature of the redox mediator allow for this control. The lateral charge propagation can be precisely tuned from an extremely slow to a very fast process.