Synthesis and characterization of thin films of palladium (II) phthalocyanine and its derivatives using the thermal evaporation technique

Abstract

This study targeted the synthesis of palladium(II) phthalocyanine (PdPc), palladium(II) tetranitrophthalocyanine (O-PdPc) and α-polymorphic palladium(II) phthalocyanine (α-PdPc) thin films, all of which were deposited on glass substrates using the thermal evaporation technique. From the spectroscopy analysis, it was observed that the B-band absorption of these films occurred in the 310–350 nm range. The peaks observed in the Q-band region, which occurred in the 634–715 nm range, were responsible for the green color of this complex. These transitions were assigned to $$\text{ }\!\!\pi\!\!\text{ - }\!\!\pi\!\!\text{ *}$$ . The UV–VIS spectra of palladium (II) phthalocyanine displayed a narrow Q-band and split bands; the split bands indicate the presence of monomeric and dimeric forms of palladium (II) phthalocyanine. Analysis of optical absorption data of the deposited films revealed direct band gap energies of 3.68, 3.10 and 3.54 eV for PdPc, O-PdPc, and α-PdPc, respectively. The surface morphology of the thin films was investigated by Atomic Force Microscopy, which showed that the polymers grew in aggregated rows.