Carbon Black-Gelatin Composite Thin-Film Chemiresistor with Large Response to Chemical Vapors

This paper proposes a new carbon black composite thin film and its depositing method. The thin film functions as a chemiresistor which changes its resistance in response to gas vapor exposure. A composite of carbon black (CB) powder and a gelatin (GE) polymer is used as the resistor material. A microelectrode structure is formed on a glass substrate by using microfabrication. A mixture solution of CB and GE is deposited on the microelectrode by a needle dispenser to form the chemiresistor with a thickness of approximately 400 nm. The vapor response of the chemiresistor is tested for water and ethanol at room temperature. The chemiresistor exhibits extreme large response (200∼300% in resistance increment) upon exposure to these vapors.