Hydroxyquinoline-coordinated organometallic complex nanowire and nanosheet for the dielectric layer of capacitors

Abstract

Understanding the mechanism of electron transfer in organometallic dielectric materials has been a major focus for capacitor applications. The present study reports four 8-hydroxyquinoline-based organometallic complexes and uses them as a dielectric layer for capacitors to analyze their capacitance (C), real and imaginary dielectric constants (ε′ and ε′′), loss factor (tan δ), dc and ac conductivity (σ_dc and σ_ac), as well as the influence of morphology on their dielectric and electrical properties. These components were prepared using radio frequency (RF)-sputtering deposition and characterized by FESEM and LCRmetry methods. Molecular analysis of the dielectrics was undertaken using XRD, EDX, DRS, ¹H and ¹³C NMR, Raman, FT-IR and PL spectroscopy techniques. Based on the results, an f-dependent damping of C was observed for AlQ₃, ZnQ₂ and CdQ₂ dielectrics, while ε′ remained unchanged, and the ε′′ and tan δ of the dielectrics experienced a decrease and an increase vs. f and T, respectively. The value of σ_ac indicated an upward trend vs. f, which is linked to polarization of the nanowire and nanosheet dielectric layers. From the molecular aspect, symmetric structures inhibit aggregation of charge carriers and dipole contributions as well as interfacial polarization due to intramolecular charge transfer (ICT), metal-to-ligand charge transfer (MLCT) and ligand-to-metal charge transfer (LMCT) mechanisms. Finally, this research highlights the dielectric properties of organometallic materials to clarify the electron transfer (ET) mechanism for designing materials for dielectric layers.