Using Deposition Rate to Control Liquid Crystal-like Order in Vapor Deposited Organic Glasses*

Physical vapor deposition can prepare glassy materials with high degrees of structural anisotropy compared to liquid-cooled glasses. In this work, Posaconazole, a molecule with no known liquid crystal phases, is vapor-deposited to create smectic-like glasses with a high degree of orientational and positional order [Bishop et. al. PNAS 116, 21421 (2019)]. Deposition parameters are varied to prepare glasses with a range of liquid crystal-like order. We show that increasing the substrate temperature and decreasing the deposition rate have the same effect upon vapor-deposited glass structure, and describe the relationship using a “Deposition Rate-Substrate Temperature Superposition”. We expect that this superposition principle can be used to understand surface dynamics during vapor deposition, in order to optimize structural order in glasses for organic electronic applications.