The Study of Electrical Conductivity and Dielectric Relaxation in the Organic Ferroelectric Diisopropylammonium Iodide (dipaI)

In this work, we delve into the dielectric response and electrical conductivity behavior of the innovative organic ferroelectric Diisopropylammonium Iodide (dipaI), with a focus on power dispersion and the universal relaxation law. We employ impedance spectroscopy, dielectric relaxation, and AC conductivity analyses across a broad spectrum of temperatures (343 K to 443 K) and frequencies (1 kHz to 20 MHz). Using the Maxwell–Wagner capacitor model, we elucidate the complex impedance using an equivalent circuit. In the equivalent circuit, elements like resistors and capacitors are arranged in a series and parallel configuration to represent the dielectric and conductive characteristics of the material. By analyzing the impedance spectrum using this model, we distinguish between the contributions from grain interiors and grain boundaries. The investigation of dielectric relaxation involves the importance of the Havriliak-Negami (HN) formula to interpret experimental findings. Unlike simpler models like the Debye relaxation, which assumes a single, discrete relaxation time, the HN formula accounts for a distribution of relaxation times, providing a more nuanced description of how polarization evolves over time. Additionally, the universal power law utilizes the parameter 'n' to describe the behavior of the electrical conductivity on the frequency, which is predicated on the hopping of charge carriers over potential barriers.