EFFECT OF SUBSTRATE TEMPERATURE ON THE STRUCTURAL AND OPTICAL PROPERTIES OF NiTsPc THIN FILMS
Abstract
Nickel(II) phthalocyanine-tetrasulfonic acid tetrasodium salt (NiTsPc) thin films were deposited on glass substrates at different substrate temperatures (Ts) by chemical spray pyrolysis (CSP) technique. The substrate temperature varied from 110∘C to 310∘C in 50∘C steps. The substrate surface temperature is the main parameter that determines the film morphology and properties of the thin films. The structural properties of the deposited NiTsPc thin films were investigated by X-ray diffraction (XRD) and from the obtained results, it was shown that depositing thin films using 210∘C as Ts results in higher crystallinity. Atomic force microscope (AFM) was employed to obtain the surface topography and to calculate the roughness and grain size. The smoothest thin film surface was obtained when using at 160∘C, while the highest roughness was obtained at 310∘C. The optical properties were investigated by ultraviolet visible (UV-Vis) spectrophotometer and fluorescence spectrophotometer. From the absorption spectra recorded in the wavelength range 190–1100nm, two absorption bands were observed, which are known as Soret and Q-band. By observing the absorption spectrum, it can be concluded that the deposited thin films at 110∘C–310∘C have direct energy gap. From Tauc plot relation, the energy gap (Eg) was calculated. The values of the energy gap were between 3.05 and 3.14eV. It was observed that different Ts highly affects the structural and optical properties of the deposited thin films. The crystallinity, grain size, roughness and the optical properties were strongly affected by the different substrate temperatures.
