Polymorphism and Phase Control in Titanyl Phthalocyanine Thin Films Grown by Supersonic Molecular Beam Deposition

Abstract

Polymorphism in the growth of titanyl phthalocyanine films on dielectric substrates has been systematically studied by UV absorption and micro-Raman analyses, correlating structure and optical properties. We explored different growth regimes as a function of substrate temperature and growth rate using hyperthermal seeded supersonic beams. We identify and discuss specific signatures in micro-Raman spectra specifically correlated to the different phases and demonstrate the unprecedented ability of growing crystalline films and controlling the relative abundance of the different phases (amorphous, phase I, and phase II) by the beam parameters. We envisage the very promising perspective of controlling polymorphism at low temperatures via supersonic beam growth, paving the way for better performing devices.