Effect of Lasing Pulses Number on the Structural, Morphological, and Optical Properties of Potassium Permanganate (KMnO4) Nanostructured Thin Films

Potassium permanganate (KMnO4) thin films have been deposited by pulse laser technique on glass substrates at 250 degrees C. The influence of lasing pulses number (thickness film) has been studied on the morphological, structural, and optical properties of KMnO4. The structure of KMnO4 films has been investigated by XRD. All films have polycrystalline and orthorhombic structure with three notable peaks along (210), (112), and (110) planes for film of lasing pulses of 75, and for film with 100 pulses the notable preferred orientations are along (210), (212), and (110) planes. The notable preferred orientations for film of (no. 125 pulses) are along (210), (102), and (110) planes. The XRD pattern confirms presence of MnO2 along (110) plane of all films according to thermal decomposition of KMnO4. For all preferred orientation, the crystallite size is increased as the number of pulses increasing. FESEM studies denote that the films microstructure has regular distribution of spherical shaped nanoparticles which improves as the number of pulses increasing. FTIR analysis shows presence of KMnO4 at 520-1000 cm(-1). and the distributions of functional groups were changed by KMnO4 presence. UV-VIS spectroscopy indicates that the films have absorption coefficients greater than 104 cm(-1) in the UV-visible region, and a high transmission (40-84%) spectrum in NIR and visible regions. The bandgap of the synthesized films is direct and slightly decreased from (1.59 eV) to be (1.55 eV) and (1.52 eV) when the number of laser pulses increased.