Dense Solid Mixtures to Multifunctional Hybrid Carbon/Low Z Networks

点击翻译按钮获取中文摘要

Nontechnical Abstract:Most materials in the universe experience extreme conditions of high pressure and high temperature, which exist deep in the planets and stars. Under such conditions, first- and second-row (or low Z) elemental solids, while existing as simple molecular or elemental solids at ambient conditions, form unusual and highly dense network structures. These materials are extremely hard, have high energy density, and exhibit novel optical and electronic properties. These novel properties arise from collective behaviors of 3D network structures of low Z elements with high phonon frequencies, thermal conductivities, cohesive energies, and strong electron-phonon couplings. The structures and properties of these densely packed low Z solids, therefore, can be viewed as nature's windows to unexplored novel structures and properties beyond those of diamond and transition metal compounds. However, these materials are often formed at formidable pressures and may be unstable at normal conditions; only a few systems have been recovered, limiting the materials within a realm of fundamental scientific discoveries. Therefore, an exciting new research area has emerged on understanding and, ultimately, controlling the stability, bonding, structure, and properties of low Z extended solids.Technical Abstract:This project aims to develop multifunctional hybrid carbon/low-Z extended solids amenable to stabilization at ambient conditions via kinetically controlled processes in heterogeneous solid mixtures. State of the art dynamic-diamond anvil cell experiments coupled with time-resolved Raman and synchrotron X-ray characterization are used to probe metastable interfacial structures and exploit the presence of internal chemical pressure and dynamic shears, thereby lowering the external transition pressure while enhancing the miscibility between two dislike solids. Through scientific discoveries and innovative material developments, the project elucidates the fundamental principles of high-pressure chemistry and demonstrate the revolutionary capabilities of hybrid carbon/low Z framework materials for hydrogen storage, chemical energy depository, and nonlinear optical and electronic applications. The project also provides graduate and undergraduate students with significant hands-on opportunities to learn experimental technologies at our institution, at the synchrotron and neutron facilities, and in national laboratories. Because of the multidisciplinary nature of this effort, these students are gaining fundamental knowledge across many academic disciplines of solid-state chemistry, condensed matter physics, and materials and planetary sciences.