Hybrid gas sensing utilizing localized surface plasmons of gold colloid and a quartz crystal microbalance

Gas sensing properties were investigated using localized surface plasmons (LSPs) and a quartz crystal microbalance (QCM). A thin film of polyvinylalcohol (PVA) and gold colloid (20 nm in diameter) was deposited on the QCM substrate, and the gas responses of the optical absorption of gold colloid LSP and the QCM frequency were simultaneously observed. Vapors of water, ethanol and methylamine in N2 were detected. The optical absorption spectra changed with the gas adsorption and desorption, and the gas response could be repeatedly observed. Furthermore, the relationship between the QCM frequency and the optical properties depended on the vapor species. Hybrid sensing can be used for detection and discrimination of various vapor adsorptions.