2, University of Missouri – Kansas City, Kansas City, Missouri, United States
3, Missouri State University, Springfield, Missouri, United States
We develop a novel methodology for accurate design and fabrication of complex disordered solids using a combination of advanced experimental and computational techniques. Complex disordered solids are non-crystalline materials for which the fundamental building blocks are typically molecules or molecule fragments, and therefore they have great potential for tunable structure and properties for various
applications. However, the complexity and high degree of freedom in their structure impose substantial challenges to the design and optimization of these materials. This presentation will focus on the structural characterization of polymer derived amorphous hydrogenated boron carbide thin films using 4-dimensional scanning transmission electron microscopy (4D-STEM). The 4-D STEM utilizes electron nanoprobes and the new-generation fast pixelated STEM detector, which records the diffraction patterns from individual nanoscale volumes of the material. The fluctuation and angular correlation analyses of the diffraction patterns can provide the unprecedented details of the structural heterogeneity, including the size, distribution, connection, and volume fraction of medium range ordering (MRO). We show that the MRO
in amorphous hydrogenated boron carbide can be comprised of the connection and networking of the icosahedral short-range clusters, and the MRO can directly affect the important physical and electrical properties of the films. Our finding is promising as it could greatly expand the breadth of materials-by-design approaches by flexibly tuning the structure of disordered materials to achieve desired properties.