Optical Constants of Palladium Phthalocyanine Derivative Thin Films

Ellipsometric parameters of a series of spin-coating thin films of palladium phthalocyanine derivatives with bromine and tetraalkoxyl substitutes PdPc(OC₈H_{17 4}Br_m, m = 0,2,3,4 are determined from a rotating analyser-polarizer type of scanning ellipsometer. The optical, dielectric constants and absorption coefficients of the films in the 500-800 nm wavelength region are reported. The results show that refractive index N (N = n-k), dielectric constant ε (ε = ε₁ - ε₂) and absorption coefficient α in the region 500-800 nm are influenced by bromine atom substituted on the conjugated phthalocyanine ring regularly. It is found that there is approximately linear relationship between the resonance absorption wavelengths of the films and the number of bromine atoms substituted on the phthalocyanine ring.