Engineering Durability and Processability: Electronic Tuning in Disordered Coordination Polymers W911NF-17-S-002
Abstract
This proposal outlines the synthesis and characterization of a series of processable and durable materials with tunable physical properties including charge and spin transport as well as magnetic phenomena. Coordination polymer research has centered on metal nodes linked by oxygen- or nitrogen-based donors which, while easy to synthesize, often have limited electronic or magnetic properties due to intrinsically poor matching between metals and linkers. Several research groups have shown that instead using sulfur-based materials facilitates interesting physical properties such as conductivity or magnetic ordering, but a major remaining problem is the need for crystallinity. While crystalline order is advantageous for characterization, it imposes severe restrictions on processability and durability, hindering the use of these materials in applications. Recent exciting new discoveries with sulfur-based materials indicate that bulk physical phenomena can be maintained without any structural order. The use of the sulfur-based linker tetrathiafulvalene tetrathiolate (TTFtt) enables strong molecular overlap and metallic conductivity even in amorphous materials. The discovery of metallic behavior in this amorphous material now primes exploration of what other physical phenomena can be realized in amorphous materials. The metallic behavior of the amorphous material NiTTFtt, namely the long-range ballistic transport of electrons, contrasts with traditional pictures of band-structures which typically rely on highly ordered crystalline materials. In fact, defects in crystalline conductors are typically thought to degrade their transport properties. Furthermore, the high conductivity of NiTTFtt is also stable to acid/base and heat, suggesting that defect ÒrichÓ materials should also be more robust. These observations raise several exciting new fundamental and applied questions which we aim to address in this proposal. What other physical phenomena that have been traditionally limited to ordered solids can be observed in disordered materials? For instance, is it possible to make an amorphous superconductor? What properties would such a material have? How do defect tolerant materials enable new applications? Based on results with NiTTFtt, higher critical temperatures and easier processability might be expected; one possible example being spintronic ÒinksÓ which can be painted on for fabrication. Previous results now provide modular system where the electronic structure of the TTFtt linkers and the identity of the metal centers can be tuned to realize the above-mentioned physical phenomena. Preliminary investigations show the possibility of doping these systems with variable compositions of Ni and Cu to introduce spin-centers. Thus, the proposed work will result in new, durable, and processable materials with exceptional electronic and magnetic properties. This work will be guided by three objectives: I. Synthesize and Structurally Characterize TTFtt-Based CPs with Tunable Composition. II. Characterize and Program Bulk Physical Properties. III. Control Durability and Morphology Through Fabrication. These studies will prove transformational for the design of new electronic materials, and will furthermore open up exciting new avenues for operationally robust application of these materials in Army critical missions.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 28, 2023
- Source ID
- W911NF2310233
Entities
People
- John R. Anderson
Organizations
- Army Contracting Command
- United States Army
- University of Chicago