The Effect of Heat Treatment on Optical Properties of Copper (II) Phthalocyanine Tetrasulfonic Acid Tetrasodium Salt (CuPcTs) Organic Thin Films

Abstract

Copper (II) phthalocyanine Tetrasulfonic Acid Tetrasodium Salt (CuPcTs) thin films have been prepared using a simple spin coating method on glass substrates. Thin films (100 ± 5 nm thickness) annealed at temperatures of (100, 150 and 200) ∘C for one hour. The optical properties of thin CuPcTs films have been investigated in the spectral range of (300-900) nm by using the (UV-Vis) spectrophotometer. The annealed film at 100 ∘C shows the highest absorbance whereas, the lowest was at the room temperature. All films have identical absorption coefficient patterns, α in the absorption region revealed direct transition. Analysis of α as well as the dielectric constants ei and er reveal two absorption peaks in mentioned spectral region. The results showed that the optical band gaps depended on the temperature. The film annealed at 100 ∘C has the lowest optical energy gap. FTIR measurements were tested in the infrared range of (400-4000) cm− 1to evaluate the position and bonds of CuPcTs as a comparison with H2Pc as a reference. Photoluminescence spectroscopy was applied to improve the results of (UV-Vis) measurements and get more exact value of optical energy gap. The energy band gaps have been estimated as (1.83 ± 0.05) and (3.18 ± 0.04) eV for Q and B bands respectively. In this work, the Capacitive-Resistive temperature sensor has been fabricated. The sensor shows response to variation of temperature in the range of (RT-200) ∘C and the response time of ≈ 20 ± 5 Sec. For two electrodes (Aluminum and silver), our results have shown that the aluminum electrode has a higher capacitance and resistance than silver electrode depending on the different frequency values. While the silver electrode has the shortest response time.