Hybrid Semiconductors Design Rules and Material Applications

Abstract

Metal-organic frameworks are highly ordered arrays of periodic inorganic clusters, spatially separated by organic linking units. Their diverse chemical compositions lend them to by applied to a varietyof applications, including gas storage and separation, chemical catalysis, light harvesting and, more recently as semiconducting layers in electronic devices. Unlike the pure inorganic analogues, typical semiconductor principles (e.g. doping and defects) are not well defined in hybrid structures. But, unlike pure organic molecules, the frameworks are not entirely covalent. Thus, the application of electronic structure theory can provide significant insight into the fundamental chemistry of these hybrid materials.

In general, these perfect crystalline frameworks are intrinsic insulators: They are wide band gap, poorly conducting materials. To modulate their properties for electronic and catalytic applications both inorganic and organic chemistry must be harnessed. As a starting point, a description of electron energies in porous materials (both in their equilibrium state and deviations induced by pressure) is presented, followed by a series of investigations into their modulation through ligand design. The ligand design also determines other properties, including material density and magnetic ordering. The work concludes with three studies that demonstrate the symbiosis of theory and experiment, showing examples of tailored metal-organic frameworks for semiconductor applications and providing scope for future hybrid materials design.

Date of Award	1 Jul 2015
Original language	English
Awarding Institution	University of Bath
Supervisor	Aron Walsh (Supervisor)