Structure formation, optical properties and energy loss functions of meso-tetraphenylporphyrin manganese(III) chloride complex thin films for energy conversion applications

Thin films of meso-tetraphenylporphyrin manganese chloride complex (MnClTPP) have been prepared by evacuated thermal evaporation technique. The structure formation of MnClTPP films has been identified using atomic force microscopy and X-ray diffraction techniques. The pristine MnClTPP films revealed amorphous structure, whereas after annealing temperature up to 490 K, the films turned to nanocrystalline structure formation. The spectrophotometric measurements of transmittance, absorbance and reflectance of pristine and annealed films have been carried out in spectral range 200-2000 nm. The absorbance revealed many electronic transition bands including high intense Soret band (B), Q-band, and two other weaker (M and N) bands extended in UV-visible spectrum. Optical constants (refractive index and absorption index) of pristine and annealed films were determined. The absorption edge analysis was performed to estimate the type of electronic transitions and the value of optical band gap. Additionally, the surface and volume energy loss functions of pristine and annealed MnClTPP films have been estimated. The annealing process improved the performance of those films and reduced the values of energy loss functions that would be utilized a potential material in energy conversion applications.