부산대학교 도서관

Thin films of metallic nanowire bundles derived from the Chevrel compound Li[Mo.sub.3][Se.sub.3] undergo reversible increases of their electrical resistance (up to 70%) upon exposure to vapors of organic solvents (Qi, X. B.; Osterloh, F. E. d. Am. Chem. Soc. 2005, 127 (21), 7666-7667). Using quartz crystal microbalance measurements with four analytes, we demonstrate here that the temporal and steady-state resistance changes of the films depend on the time following the adsorption and on the number of molecules that adsorb to the nanowire films at a given pressure. The adsorption ability of the films and the corresponding film resistance increase in the row: hexane < THF < ethanol < DMSO, closely following the polarities of the solvents. On average, ~[10.sup.5] analyte molecules per Li[Mo.sub.3][Se.sub.3] unit are required to produce a measurable electrical response. Atomic force microscopy scans on nanowire films reveal that analytes deposit on top of the nanowire bundles and cause the films to swell by 46% in volume. The temporal and steady-state resistance data of the Li[Mo.sub.3][Se.sub.3] chemiresistors can be explained by assuming that coating of the nanowire bundles with analyte molecules reduces the interwire charge transport in the films.