Electrical, optical and morphological properties of a new chromogenic calix[4]arene derivative

We have studied electrical properties of ITO/azo-calix[4]arene/Al diodes by means of current–voltage measurement and impedance spectroscopy in a wide frequency range. The devices with an ITO/azo-calix[4]arene/Al structure could be modeled as a simple combination of resistors and capacitors. The impedance spectra can be discussed in terms of an equivalent circuit model designed as a parallel resistor Rp and capacitor Cp network in series with resistor Rs. We extract numerical values of these parameters by fitting experimental data. Relaxation processes have been identified too from the impedance spectroscopy. Their values deduced from fitting experimental data to the model have given a dielectric relaxation time in the ms range and an exponential trap distribution.