Optical Parameters and Absorption of Azo Dye and Its Metal-Substituted Compound Thin Films

We determine the complex refractive indexes N(N = n-ik), dielectric constants ε(ε = ε₁ - iε₂), and absorption coefficients α of a new azo dye 2-(6-methyl-2-benzothiazolyazo)-5-diethylaminophenol(MBADP)-doped polymer and its nickel- and zinc-substituted compounds(Ni-MBADP and Zn-MBADP) spin-coated thin films from an scanning ellipsometer in the wavelength 400-700 nm region. Metal chelation strongly (about one times) enhances the optical and dielectric parameters at the peaks and results in a large bathochromic shift (50-60 nm) of absorption band. Bathochromic shift of Ni-MBADP is about 10 nm larger than that of Zn-MBADP due to different spatial configurations formed in the metal-azo complexes.