Linear and nonlinear optical characteristics of manganese phthalocyanine chloride/polyacetate sheet: Towards flexible optoelectronic devices

Thin films of manganese phthalocyanine chloride (MnPcCl) were prepared using a thermal deposition onto a polyacetate sheet substrate. The structure analyses of the obtained MnPcCl thin films of different thicknesses ranging from 55 to 125 nm were investigated using the X-ray diffraction technique. The transmittance and reflectance of MnPcCl thin films were measured at the normal incident light in the 200–2500 nm wavelength range. The absorption coefficient analysis revealed that the films were characterized by indirect allowed transition with two energy gaps. The Wemple-DiDomenico single oscillator model explained the refractive index's dispersion behavior, and dispersion parameters were calculated. The third-order nonlinear optical susceptibility (χ⁽³⁾) and nonlinear refractive index (n₂) were determined using Miller's principles. Optical limiting behavior was estimated using the He–Ne (633 nm) and green (533 nm) lasers power. The obtained results indicate that MnPcCl films are excellent nonlinear optical materials for optical limiters.