Effect of nozzle to substrate distance on the structural and absorption properties of nickel (II) tetrasulfonated phthalocyanine thin films

Abstract

The effect of nozzle to substrate distance (dns) on the structural and absorption properties of nickel (II) tetrasulfonated phthalocyanine (NiTsPc) thin films deposited by chemical spray pyrolysis technique has been characterized by x-ray diffraction (XRD), atomic force microscope (AFM) and ultraviolet visible (UV–vis) spectrophotometer. The nozzle to substrate distance was varied between 20 and 40 cm. The XRD data showed that different dns affect the crystallinity of the deposited NiTsPc thin films and it was shown that the optimum crystal structure was obtained when dns was 35 cm. Grain size and roughness were calculated from the topographical images obtained from AFM. The results of AFM showed that the smoothest surface of the deposited thin films was when using 30 cm as distance. The obtained absorption spectra obtained from UV–vis showed two absorption bands (Soret and Q-band), and from the calculated absorption coefficient (α) it was shown that the deposited NiTsPc thin films have direct allowed optical energy gap. The energy gap was calculated from Tauc relation, and the results showed that varying dns affected the values of optical energy gap. The energy gap obtained from Tauc plot was between 3.07 and 3.12 eV. It can be concluded that varying dns has a significant impact on the structural and absorption properties of the deposited NiTsPc thin films.