CAREER: Coordination Polymer Superlattices with Tailored Properties through Chemical Vapor Deposition Synthesis

Johns Hopkins University, Baltimore MD

Investigators

Abstract

Non-Technical Abstract Coordination polymers are versatile materials that are currently used to filter pollutants, store energy, and convert raw materials into useful chemicals. Recently, there has been great interest in using the extensive structural and chemical tunability of these materials to make a new generation of electronic devices, such as switches, sensors, and smart energy storage systems. However, the poor electrical performance of these materials, and a lack of synthetic methods capable of creating desired material properties has slowed progress. This CAREER project, supported by the Solid State and Materials Chemistry program in the Division of Materials Research, addresses these challenges by developing new methods to grow high quality crystalline coordination polymers from the gas phase. Furthermore, this proposal addresses the need to improve the electrical performance of these materials by creating a new material architecture called a superlattice, which is composed of single crystal sheets of various coordination polymers stacked on top of one another. The composition, structure, and layering of the individual sheets can be controlled. Because structure and function are so tailorable in the superlattice, it has the potential to support enhanced and novel properties, allowing it to exceed the performance limits of conventional polymers and solid-state materials. This research can enable technological advances in energy storage and conversion, and spawn a new generation of filters, actuators, sensors, and optical/electronic devices. Many of these technologies can be used to assure the sustainability and improved welfare of society. The research innovations and methods used in this research provide a multitude of student training opportunities in the synthesis, structure-property determination, and application of materials. In addition to the research objectives described in this proposal, the principal investigator is introducing two education and outreach activities: a podcast channel focused on materials science topics, and an online crowd-sourced database that curates materials synthesis protocols. These activities aim to increase the participation of under-represented minorities in STEM fields and to build a research infrastructure to accelerate the dissemination and verification of research protocols. Technical Abstract Coordination polymers (CPs) can be designed to express a diverse array of structures, porosities, and chemistries rendering them useful for applications in energy storage, separations, and catalysis. However, CPs with more complex functionalities and responsive properties are desired if they are to be successfully integrated into electronic devices. The principal hypothesis of this project, supported by a CAREER award through the Solid State and Materials Chemistry program in the Division of Materials Research, is that a CP superlattice can support complex, multivariate, and responsive properties. A superlattice comprising layered two-dimensional CP crystal lattices is an attractive architecture, because its inherent hierarchies of structure and composition can be tailored to promote desired or emergent physical properties. This CAREER project addresses the development of chemical vapor deposition methods for the tailored synthesis of CP superlattices and the study of these materials' dynamic and responsive properties. Chemical vapor deposition (CVD) is introduced as a strategy for the preparation of high-quality crystalline CP superlattices. The project focuses on three core objectives. First, the scope and mechanism of chemical vapor deposition synthesis of CP superlattices are being established. Second, transport studies conducted on devices fabricated on single crystals of CP superlattices are being used to elucidate their electronic properties. Third, heterostructured CP superlattices with multivariate and responsive properties are being developed and their potential to surpass the performance limits of conventional bulk 3D materials is being determined. In addition to the research objectives of this project, the principal investigator has introduced two education and outreach activities: a podcast channel focused on materials science topics, and an online crowd-sourced database that curates CVD synthesis protocols. These activities aim to increase the participation of under-represented minorities in STEM fields and to build a research infrastructure to accelerate the dissemination and verification of research protocols. 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.