Vacuum vapor deposited thin films of a perylene dicarboximide derivative: Microstructure versus deposition parameters

摘要: The microscopic physical structure in thin films of vapor deposited, large heterocyclic organic molecules is strongly dependent on the deposition parameters. scale microstructure can vary enormously compared to inorganic systems, affecting macroscopic properties. Multiple polymorphs frequently characterize these systems. We have extended our previous work with perylene dicarboximides include a phenethyl derivative. Films 300–1000 A thickness range, deposited metal and transparent substrates at varying rates substrate temperatures from −165 155 °C, without vacuum annealing, been characterized by scanning electron microscopy, ultraviolet/visible, infrared (IR) spectroscopies, polarization modulation reflectivity changes. Evidence presented for critical temperature between −22 −32 °C. Also polymorphic phase sensitivity rate demonstrated, consistent an exothermic peak observed differential calorimetry material, annealing induced molecular reorientation reflection absorption IR.