Optical, electrical and sensing properties of β-ketoimine calix[4]arene thin films

Optical, electrical and ion sensing properties of β-ketoimine calix[4]arene thin films have been investigated. These calix[4]arene derivative films exhibit absorption spectra with a resolved electronic structure in the UV–vis and the energy gap was found to be 3.65 eV. Electrical properties of ITO/β-ketoimine calix[4]arene/Al devices have been investigated by I–V characteristics and impedance spectroscopy measurements. The conduction is governed by space-charge-limited current (SCLC) mechanism. The impedance spectroscopy study showed a hopping transport process, a typical behavior of disordered materials. The device was modeled by a single parallel resistor and capacitor network in series with a resistance. The β-ketoimine calix[4]arene was used for the conception of the novel optical chemical sensor and the detection of Cu2+ ions was monitored by UV–visible spectroscopy. The linear dynamic range for the determination of Cu2+ has been 10−5–10−3.7 M with a detection limit of 10−5 M. The characteristics of this optode such as regeneration, repeatability, reproducibility, short-term stability, life time and ion selectivity have been discussed.