Dielectric and Electrochemical Sensing Studies of Li Co-doped LaAlO₃:Ce³⁺Nanopowders

Abstract

We report the structural, morphological, dielectric, and electrochemical sensing studies of Li co-doped LaAlO₃:Ce³⁺_1.5 nanopowders successfully synthesized via a simple combustion technique utilizing sugar as fuel. Powder x-ray diffraction analysis confirmed that the prepared nanopowders have a pure rhombohedral crystal structure. The average particle size of the prepared nanopowders was found using Scherrer’s relationship and the W-H method and was found to be in the range of 40–60 nm. Fourier-transform infrared spectra revealed the strong transmittance peaks at 455 cm⁻¹, 668 cm⁻¹, 832 cm⁻¹, 1044 cm⁻¹, 1389 cm⁻¹, 1592 cm⁻¹, 2432 cm⁻¹, and 3441 cm⁻¹. The formation of nanoparticles was evidenced by scanning electron micrographs. The optical band gap of the prepared nanopowders was estimated. The dielectric and electrical features of the prepared nanopowders were carried out in the frequency range from 10 Hz to 8 MHz at RT utilizing an LCR meter. The prepared nanopowders showed high dielectric constant and low dielectric loss in low- and high-frequency regions, respectively. Using a Cole–Cole plot, the grain boundary contributions in the prepared nanopowders have been explained. Using cyclic voltammetry and chronoamperometry, the electrochemical sensing performance of the Li⁺ co-doped Ce³⁺ activated LaAlO₃nanostructure was investigated. This demonstrated improved sensing behavior due to the intermediate energy levels formed by the additional dopant, Ce³⁺ and co-dopant, Li⁺. The introduction of Li⁺ ions into the LaAlO₃:Ce³⁺ nanostructures improves the performance of these materials in various applications. The novelty of dielectric and electrochemical sensing studies of Li co-doped LaAlO₃:Ce³⁺_1.5 nanopowders indicate an approach to investigate the electrical properties of a new material which finds potential applications in electrochemical sensing devices.