Studies on structural and optical properties of thermally evaporated nanocrystalline thin films of meso-Tetraphenylporphyrin manganese(III) chloride

Thin films of meso-Tetraphenylporphyrin manganese(III) chloride (MnTPPCl) were prepared by conventional thermal deposition technique, under vacuum (10−4 Pa), on glass and quartz substrates. X-ray diffraction (XRD) technique, Fourier-transform Infrared (FT-IR) technique and scanning electron microscope (SEM) were used to investigate crystalline and molecular structures, and morphology of MnTPPCl in powder form, and the as-deposited thin films. Absorption spectra of thin films were recorded in the wavelength range from 200 to 2500 nm by using Spectrophotometric measurements. Seven distinct absorptions were detected in MnTPPCl thin films in the range between 1.9 and 5 eV. The type of the optical transition and optical energy gap were estimated from the analysis of the absorption coefficient data. In the present work, dispersion parameters: oscillator energy, dispersion energy, optical dielectric constant at higher frequency, and Lattice dielectric constant were calculated as well as many other optical parameters. Nonlinear absorption coefficient spectrum of MnTPPCl thin film was obtained utilizing a linear optical parameter. The cyclic voltammetry measurements were employed to calculate HOMO-LUMO gap in the voltage range from − 2 to + 2 V.