Electrical study at interfaces in facile designed Fe0.03Zn0.97O@carbon core–shell nanocomposite using impedance spectroscopy

• Published in: Journal of alloys and compounds 2024-03, Vol.978, p.173353, Article 173353
• Main Authors: Rafi, M., Ghazanfar, U., Arfan, M., Nadeem, M.
• Format: Article
• Language: English
• Subjects: Band gap; Core shell structures; Dielectric permittivity; Impedance analysis; Transmission electron microscopy
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2023.173353

Semi-hexagonal and semispherical shape Fe0.03Zn0.97O@C core shell nanocomposite is prepared through the hydrothermal method. Topographical understanding of this material is carried out using transmission electron microscopy and scanning electron microscopy which highlights the role of interfaces and grain in electrical conduction. Polycrystalline nature of as synthesized material is studied using refined XRD spectrum which also helps to calculate the average crystallite size (22 nm). Comprehensive temperature-dependent impedance spectroscopy is performed on sintered pellet, in order to study different electroactive regions. High dielectric constant with the low tangent loss for subject material is recorded against an applied frequency of 1 Hz to 107 Hz in a broad temperature variation from 348 K – 423 K. Effect of variation in temperature is observed on ac conductivity (5.9 × 10−8 Scm−1 to 1.5 × 10−5 Scm−1), which is well explained using correlate barrier hopping (CBH). The temperature-dependent physical parameters like binding energy, barrier height, and minimum hopping distance are also well explained here. The small polaron hopping model is used to fit the experimental data and estimate activation energies of ions through grains and interfaces are 0.73 eV and 0.75 eV respectively. The ac conductivity with enhanced dielectric characteristics makes this material suitable for practical application in energy storage and electronic devices. The optical characteristics are explored using diffuse reflectance spectroscopy to estimate the redshift in the band gap (3.18 eV) using the Kubelka-Munk formulism. [Display omitted] •The topography of grans and interfaces are well resolved using transmission electron microscopy (TEM).•Comprehensive temperature dependent impedance spectroscopy is performed on sintered pellet to study different electroactive regions. High dielectric constant with low tangent loss for subject material is recorded against applied frequency of 1 Hz to 107 Hz in a broad temperature variation from 348 K – 423 K.•Effect of variation in temperature is observed on AC conductivity (5.9 × 10−8 Scm−1 to 1.5 × 10−5 Scm−1), which is well explained using correlate barrier hopping (CBH).•Temperature dependent physical parameters like binding energy, barrier height and minimum hopping distance are also well explained here.