Layer-by-layer chemical deposition technique for thin film assembly of deposited nano-sized magnesium(II)–5,7-dinitro-8-hydroxyquinolate: Characterization and spectral–optical–electrical properties

Abstract

Layer-by-layer (LBL) chemical deposition technique was implemented as a low cost and efficient methodology for rapid synthesis and assembly of deposited thin films of nano-sized magnesium(II)–5,7-dinitro-8-hydroxyquinolate complex, Mg[(( NO 2) 2- 8HQ) 2]. The stoichiometry of deposited nano-sized complex was characterized as a 1:2 ratio based on metal to ligand without contribution of the nitro-group. Further structural characterization and identification were also monitored by using Fourier Transform infrared spectroscopy (FT-IR) in order to confirm the possible mode of bonding in the deposited nano-sized Mg[(( NO 2) 2- 8HQ) 2] complex. Thermal gravimetric analysis (TGA) of the ligand and complex were studied and compared to evaluate the possible incorporated thermal stability characteristics. Surface imaging of assembled thin film was performed by using scanning electron microscopy (SEM) to confirm high homogeneity in surface particles distribution with average particle size in the range of 30–50 nm. The absorption spectrum of Mg[(( NO 2) 2- 8HQ) 2] thin film was recorded in the spectral region 250–1000 nm. The optical transmission and reflection spectra of the films have been recorded within the wavelength range 250–2500 nm. The optical parameters of the films, such as absorption index, α, refractive index, n, band gap, E g , dielectric constants, ε 1 and ε 2 and dissipation factor, tan δ, have been also determined. Two activation energies were determined from the temperature dependence of the dark electrical conductivity. Hopping conduction parameters of Mg[(( NO 2) 2- 8HQ) 2] have been calculated by employing the variable range hopping model.