Using 4D STEM to probe mesoscale order in molecular glass films prepared by physical vapor deposition

• DOI: 10.48550/arxiv.2302.10818
• Publication Date: 2023-01-01
• Authors: Debaditya Chatterjee; Shuoyuan Huang; Kaichen Gu; Jianzhu Ju; Junguang Yu; Harald Böck; Yu Lian; M. D. Ediger; Paul M. Voyles
• Keywords: Nanometre; Deposition; Physical vapor deposition; Mesogen

Physical vapor deposition can be used to prepare highly stable organic glass systems where the molecules show orientational and translational ordering at nanoscale. We have low-dose four-dimensional scanning transmission electron microscopy (4D STEM), enabled by a fast direct detector, map columnar order in glassy samples of discotic mesogen using 2 nm probe. Both deposited liquid cooled films domains similar orientation, but their size varies from tens hundreds nanometers, depending on processing. Domain sizes are consistent with surface diffusion mediated during film deposition. These results demonstrate ability 4D STEM characterize mesoscale structure molecular system which may relevant electronics.