Cu(II) 5,10,15,20-tetrakis(4′-isopropylphenyl) porphyrin based surface-type resistive-capacitive multifunctional sensor

An organic semiconductor Cu(II) 5,10,15,20-tetrakis(4'-isopropylphenyl) porphyrin (CuTIPP) was synthesized and investigated as an active material in resistive-capacitive multifunctional sensor. A thin film of the CuTIPP was deposited by thermal evaporator on a glass substrate with preliminary deposited silver electrodes and Ag/CuTIPP/Ag surface-type multifunctional sensor was fabricated. Thickness of the CuTIPP film was 100 rim. Area of the semiconducting channel between metallic electrodes was 40 mu m x 21 mm. A change in electrical resistance and capacitance was observed with the increase of temperature, relative humidity and illumination. An equivalent circuit of the Ag/CuTIPP/Ag capacitive-resistive humidity, temperature and illumination sensor was developed. Humidity, temperature and illumination dependent capacitance-resistance properties of this sensor make it beneficial for use in humidity, temperature and lux multimeters. (C) 2009 Elsevier B.V. All rights reserved.