Electrical and electrochemical properties of the MEH–PPV and MEH–PPV doped calix[4]arene derivative layers for the detection of Cu2+ and Na+ ions

Abstract

A modified ITO electrode based on conducting polymer (MEH–PPV) matrix doped with the calix[4]arene molecules (β-ketoimine calix[4]arene) is deposited by spin coating. The carrier transport mechanism of the MEH–PPV and MEH–PPV:β-ketoiminecalix[4]arene films is investigated by using I–V characteristics measurements. The conduction mechanisms in these thin films are identified to be a space-charge-limited current (SCLC). The dielectric behavior of the MEH–PPV and the composite β-ketoimine calix[4]arene/MEH–PPV thin films are investigated by impedance spectroscopy (IS). The Cole–Cole plots are studied showing single semicircles and the solid interfaces are modeled by an equivalent circuit. The characteristics of chemical sensors based on MEH–PPV and MEH–PPV doped β-ketoimine calix[4]arene thin films for the detection of Cu2+ and Na+ ions are investigated by electrochemical impedance spectroscopy (EIS). The experimental impedance data of the modified electrodes are modeled by an equivalent circuit using the Z-View software. The inclusion of calixarene molecules into conducting polymer (MEH–PPV) exhibited considerable rise charge transfer resistance and improves sensing properties.