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

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.