Thermal decomposition of tetrapyrazino[2,3-b]indoloporphyrazine films

Abstract

Phthalocyanines are attractive due to their advantageous properties such as chemical and thermal stability, optical and electronic properties, and ordered crystal film growth. They are finding potential applications in organic light emitting diodes, organic field effect transistors, organic solar cells and sensors. In these applications, phthalocyanines are mostly used as thin films. Thin films of organic molecules, especially phthalocyanines and porphyrins, are generally deposited by thermal evaporation in vacuum. The use of thermal evaporation allows the deposition of thin films with controlled thickness and structural properties. However, thermal decomposition of the molecules may occur during thermal evaporation. In this work, tetrapyrazino[2,3-b]indoloporphyrazine films have been prepared by both thermal evaporation and the Langmuir-Blodgett (LB) technique. The properties of the tetrapyrazino[2,3-b]indoloporphyrazine films have been investigated using various spectroscopic techniques. FT-IR, NMR and X-ray photoelectron spectroscopy (XPS) have been used to analyze the structural compositions of the films, and ultraviolet photoelectron spectroscopy (UPS) and UV-Vis spectroscopy have been performed to compare the valence electronic states and electronic transitions of the thermally evaporated and LB films.