Structural Approach to Improve the Response Characteristics of Copper Phthalocyanine Thin Film-Based NO2Gas Sensor

Abstract

AbstractIn order to realize a high-sensitivity, low temperature operable NO2gas sensor, thin films of at-form copper phthalocyanine (α-CuPc) have been deposited by vacuum sublimation. In this study, we have attempted to improve the gas-sensing characteristics through a modification of the film microstructure. Firstly, the gas sensitivity is remarkably increased by an insertion of higher-sensitive layer (vanadyl Pc film) between the α-CuPc film and the glass substrate in the low gas concentration range. Secondly, a reversibility in cycles of gas doping and dedoping is improved by film deposition on hydrofluoric acid-treated substrate. It is found from atomic force microscope analyses that this phenomenon may be closely related to a modification of the film microstructure.