Electrical detection of aqueous metal ions with metallic LiMo3Se3 nanowire sensors

ANYL 143

Mark Allen and Frank E. Osterloh, fosterloh@ucdavis.edu. Department of Chemistry, University of California, Davis, One Shields Ave, Davis, CA 95616
Films made from LiMo3Se3 nanowires are known to function as chemical sensors for the detection of molecular analytes with detection levels as low as 2.6 ppm for DMSO vapor (J. Am. Chem. Soc., 2005, 127(21); 7666-7667). In this talk we demonstrate that the same films can also detect metal ions in aqueous solution via an increase in the electrical resistance. The resistance changes occur over the course of seconds, they are entirely reversible for most ions, and their size is 1-15% of the base resistance of the films. The signals depend on the concentration of the electrolyte, and on the size and charge of the metal cation. Anions do not play a significant role, presumably, because they are repelled by the negatively charged nanowire strands.