Influence of Air Annealing and Gamma Ray Irradiation on the Optical Properties of Cl₁₆FePc Thin Films

Abstract

Metal phthalocyanines are one of the most promising candidates to be used in the fabrication of such devices. Among various phthalocyanines, Iron Hexadecachloro Phthalocyanine (Cl16FePc) has received less attention. Basic characteristics of Cl16FePc are not reported in literature. Hexadecacholoro phthalocyanines have attracted interest as possible n-type organic semiconductor with high electron mobility and good stability characteristics. In the present work we investigate the optical band gap of the Cl16FePc thin films from the optical absorption spectrum as a function of air annealing temperatures and their suitability for the fabrication of molecular electronic devices. Some optical properties of the samples were studied as a function of γ-radiation doses also. Optical transition is found to be of direct type and optical band gaps are determined by analyzing the absorption spectrum. Vacuum sublimed thin films of Iron hexadecachloro phthalocyanine were prepared at room temperature onto glass substrates at a base pressure of 10-5Torr on precleaned glass substrates using Hind Hivac 12A4 coating plant. The optical energy band gap Eg were calculated. The mechanism of optical absorption follow the rule of direct transition. In the present paper we also report refractive index, real and imaginary parts of optical dielectric constant etc. from the reflectance measurements.

Chlorosubstituted Copper Phthalocyanines: Spectral Study and Structure of Thin Films

“…According to DFT calculations, the HOMO and LUMO energy levels of CuPcCl x decrease in comparison with unsubstituted CuPc derivatives [26,27]. Koshy et al [28] investigated the effect of annealing temperature on the optical band gap of FePcCl 16 films, and considered their possible applications as active layers of molecular electronic devices. Anchar et al [29] have shown that the conductivity of CuPcCl 4 pellets is about four orders of magnitude higher than that of unsubstituted CuPc.…”

“…Ling, Bao and Erk determined that the carrier mobility of a CuPcCl 16 film deposited at an elevated substrate temperature in air-stable n-channel transistors was 10 −2 cm 2 V −1 s −1 [30]. It is known that the electrical properties of phthalocyanines and other molecular crystals are dependent upon the phase composition, morphology and orientation of molecules in thin films [6,7,28]. It is worth mentioning that in most of the abovementioned articles, the structure of thin films MPcCl x was not studied.…”

Thin films of chlorosubstituted vanadyl phthalocyanine: charge transport properties and optical spectroscopy study of structure

“…E.g., chlorine substitution in MPc was shown to modify solubility, conductivity, nonlinear optical and photochemical properties of MPc films [12,13]. In a recent work, the authors [14] studied the annealing temperature dependence of the optical band gap of the FePcCl 16 thin films and considered possible applications of the latter as components of molecular electronic devices. Furthermore, the array of rectangular microtubes of CuPcCl 16 with a large interior width of 1.4 -1.8 μm and thin walls (80 -100 nm) was synthesized and characterized by means of scanning and transmission electron 4 microscopies, XRD, FTIR, and X-ray photoelectron spectroscopy [15].…”

Partially fluorinated copper phthalocyanine toward band engineering for high-efficiency organic photovoltaics

“…19,[22][23][24][25] Halogenated phthalocyanines, such as F 16 CuPc and Cl l6 CuPc, act as n-type semiconductors. 13,[26][27][28] In halogenation, fluorination strongly affects the energy level because of the strong electron-withdrawing ability of fluorine atoms. Murdey et al have measured the HOMO and LUMO energy levels of CuPc, an isomer of F 8 CuPc, and F 16 CuPc from the results of ultraviolet photoemission and inverse photoemission spectroscopy.…”