Characterization of dense arrays of chemiresistor vapor sensors with submicrometer features and patterned nanoparticle interface layers.

The performance of arrays of small, densely integrated chemiresistor (CR) vapor sensors with electron-beam patterned interface layers of thiolate-monolayer-protected gold nanoparticles (MPNs) is explored. Each CR in the array consists of a 100-μm(2) interdigital electrode separated from adjacent devices by 4 μm. Initial studies involved four separate arrays, each containing four CRs coated with one of four different MPNs, which were calibrated with five vapors before and after MPN-film patterning.

Comparative gas sensing in cobalt, nickel, copper, zinc, and metal-free phthalocyanine chemiresistors.

The sensitivities of metallophthalocyanine (MPcs: M = Co, Ni, Cu, Zn, and H(2)) chemiresistors to vapor phase electron donors were examined using 50 nm MPc films deposited on interdigitated electrodes. Sensor responses were measured as changes in current at constant voltage. Analytes were chosen to span a broad range of Lewis base and hydrogen bond base strengths.

Selective detection of vapor phase hydrogen peroxide with phthalocyanine chemiresistors.

The use of hydrogen peroxide as a precursor to improvised explosives has made its detection a topic of critical importance. Chemiresistor arrays comprised of 50 nm thick films of metallophthalocyanines (MPcs) are redox selective vapor sensors of hydrogen peroxide. Hydrogen peroxide is shown to decrease currents in cobalt phthalocyanine sensors while it increases currents in nickel, copper, and metal-free phthalocyanine sensors; oxidation and reduction of hydrogen peroxide via catalysis at the phthalocyanine surface are consistent with the pattern of sensor responses.

Gas sensing mechanism in chemiresistive cobalt and metal-free phthalocyanine thin films.

The gas sensing behaviors of cobalt phthalocyanine (CoPc) and metal-free phthalocyanine (H2Pc) thin films were investigated with respect to analyte basicity. Chemiresistive sensors were fabricated by deposition of 50 nm thick films on interdigitated gold electrodes via organic molecular beam epitaxy (OMBE). Time-dependent current responses of the films were measured at constant voltage during exposure to analyte vapor doses.