Effect of annealing on the optical, structural and electrochromic properties of vacuum evaporated manganese phthalocyanine thin films

Abstract Thin films of Manganese Phthalocyanine (MnPc) were thermally deposited onto glass substrates and were vacuum annealed at different temperatures in steps of 50 K. Variation of the optical band gap with annealing temperature was studied for the MnPc thin films from its absorption spectra. Structural properties of the annealed MnPc thin films studied using X Ray diffraction technique yielded grain size for each annealing temperature. Cyclic voltammetry studies showed that all the MnPc thin films changed their color between green-purple-green under different redox potentials and the films annealed at 423 K had the highest electrochemical reversibility and coloration efficiency compared to the other annealed films.