A facile approach to prepare a thin film vapor sensor is demonstrated through droplet interfacial reaction on an IDA microelectrode. Scanning electron microscopy, atomic force microscopy and transmission electron microscopy analyses show that the film of the vapor sensor is composed of self-assembled gold nanocrystals in an average diameter of about 4.3 nm. The as-prepared sensor was examined by potential step method and impedance measurement, which exhibited significant DR/Ri responses and excellent cycle performance to the
volatile organic compound (VOC) vapors of acetone, methanol, styrene, benzene, toluene and ethanol. The selectivity to the VOCs with benzene ring or organic solvents suggests that the sensor is probably in line with the swelling and dielectric sensing mechanisms.
