Gas sensitive material on the basis of cholesteric-nematic mixture doped carbon nanotubes for optoelectronic NH3 gas sensor

Abstract

For nowadays the main goal for using the sensors are the investigations the new gas sensitive materials. Optical gas sensors are characterized by most of the high response. Such sensors distinguished by the high sensitivity, selectivity and stability and have long-term operation 1 . The principle of operation is based on the absorption of NH 3 gas by sensitive element of primary transducer and changing the spectral characteristics. Principle of gas sensor operation is based on the registration of shift of the wavelength minimum in spectral characteristics of cholesteric-nematic mixture (CNM). In paper as sensitive material used the CNM on the basis of BLO-61 cholesteric liquid crystal (CLC) with 5CB nematic liquid crystal (NLC) doped by single and multiwall carbon nanotubes. The optimal nanocomposite structure composition to obtain the maximum value of spectral sensitivity coefficient was determined. In paper was found the increasing the nanotubes concentration in CNM leads to increasing the spectral sensitivity coefficient independently of 5CB concentration in CNM, but the maximum nanotubes concentration was chosen to take in to account the optical transparency of experimental samples. Gas sensitive material on the basis of cholesteric-nematic mixture doped carbon nanotubes for optoelectronic NH 3 gas sensor.