Structural Profile, Lattice Dynamics, Broad Frequency Dielectric Responses, and Tuning of Optoelectronic Properties of Multiphase V2−xMnxO5−δ Compounds Systems
摘要
Compound systems with chemical empirical formula V2−xMnxO5−δ (0.05 ≤ x ≤ 0.25) were synthesized through a high-temperature solid-state reaction technique and the phase formation was confirmed with XRD analysis. The scanning electron micrographs showed densely packed flake-like particles with a size regime in the micrometer order. The stoichiometric precision of the composition according to the formulated chemical formula was verified using energy-dispersive x-ray spectroscopy. The ac conductivity, dielectric permittivity, impedance, and dielectric loss tangent were systematically analyzed over a broad frequency spectrum ranging from 40 Hz to 10 MHz. At low frequencies, the AC conductivity exhibits a behavior analogous to dc conductivity, while at 10 MHz, σₐc decreases from 8.299 × 10⁻4 S m⁻1 to 3.73 × 10⁻4 S m⁻1 as the Mn ion concentration increases from x = 0.05 to 0.25, attributed to the reduction in carrier concentration at higher mole fractions. The band gap energy was determined employing Tauc’s re-emission function, revealing a variation within the range of 2.21–2.10 eV with respect to the stoichiometry.