Crystalline materials are characterized by a structure with a regular, repeating pattern of atoms, while amorphous materials such as glass are disordered. Quasicrystalline (QC) materials are unusual in that they are ordered but not periodic, making them a fundamentally different category of materials which is neither a crystal nor a glass. The unique structure gives QC materials intriguing thermal, electrical, magnetic, optical and mechanical properties, making them useful for applications such as non-stick and thermally insulating coatings or corrosive-resistant and extremely strong materials for medical devices and surgical instruments. This CAREER award, supported by the Solid State and Materials Chemistry program within the Division of Materials Research, enables study of QC materials self-assembled from pyramid-shaped nano-sized particles (nanocrystals). The project includes detailed characterization of new QC materials’ structures and formation processes and also develops new characterization and growth methods that may be applicable to studying other soft matter assembly systems. The research offers ample fundamental and visual interest, as well as technological relevance, all of which are integrated into the PI’s education and outreach activities. YouTube movies with a jargon-free, storytelling style are created and promoted through various social media platforms. These videos take unique advantage of the connection between the beautiful and eye-catching QC patterns created by this fundamental study and real-world art, decoration and architectural design. Additionally, the project supports outreach to local high school students through an annual STEM Day.
This CAREER project, supported by the Solid State and Materials Chemistry program within the Division of Materials Research, integrates education and research on quasicrystalline (QC) superstructures assembled from pyramid-shaped nanocrystals (NCs). Self-assembly of NCs into novel superstructures is a promising approach for transporting nanoscopic properties into macroscopic materials to eventually enable highly efficient solar cells, low-energy-consumption lighting and displays, and more sensitive biological sensors. To realize these opportunities requires rational control over the formation of NC superstructures. Quasicrystals are ordered but not periodic and as such defy classification as either a crystal or a glass. The study of NC QC superlattices (QC-SLs) is in its infancy compared to efforts on conventional NC crystalline superstructures. It remains an outstanding question how NCs organize into these long-range ordered yet aperiodic lattices; methods to produce and characterize these unique materials are limited. To address these issues, the PI's group first synthesizes anisotropic pyramidal NCs and assembles them into QC superstructures. These materials are then characterized using combinations of in situ and ex situ real space methods (electron microscopies and tomography) complemented by reciprocal space measurements (electron diffraction and X-ray scattering). In addition to 2D superlattices, 3D QC supercrystals grown via microfluidics will be structurally characterized using a new super-crystallography technique. Together, these tools provide exquisite detail concerning the packing of these structures and specify the relative orientation of individual NCs. Such information clarifies how NC synthesis, superstructure formation and transformation work together to create QC superstructures. Results generated in this research are integrated into a series of outreach activities that target younger students and adults alike with compelling, visual stories designed to provoke interest in science and technology.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
