(Invited) Scalable Nanostructure Integration for Multi-Mode Chemical Sensing

Wednesday, 31 May 2017: 10:50
Eglinton Winton (Hilton New Orleans Riverside)
P. X. Gao (University of Connecticut)
Using a combination of vapor and solution phase deposition methods, scalable heterostrutured nanowire arrays have been successfully fabricated composed of metal oxide nanowire cores ~100-300 nm in diameter, ~1-30 nm thick shells of perovskite, metal oxide and noble metal nanoparticles on ceramic substrates. The nanowire structure features tuned composition, density, geometry, and dimensions through varying the deposition temperature, concentration, pH, substrate temperature, time, etc.. Multi-mode chemical sensing platform has been achieved at both room temperature and elevated temperature to include photocurrent, electrical resistance and electrochemical impedance modes. Depending on the selections of comprising materials, dimensions and post-treatment processes, trace amount decoration of perovskite, metal oxide and noble metal nanoparticle shells may enable formations of catalytic filters, sensitizers and hetero-junctions that can drastically enhance nanosensor performance in both oxidative and reductive gas atmospheres. Specifically the materials-synergy effect in metal oxide/perovskite, and metal oxide/noble metal nanowire array sensors are discussed toward sensing of various gaseous species such as O2, CO, HCs, SOx, and NOx. Toward mixture gas conditions, this new type of multi-mode nanowire array sensors allows selective and sensitive detection of multiple chemical species in a single-device platform.