Scope and novelty Thermoelectric (TE) devices convert heat into electricity and represent an important route for green technologies. They have the potential for making an impact in many fields, such as portable devices (medical applications) and smart grid systems (coupled with batteries and photovoltaics). The quality of TE materials is defined by the dimensionless figure of merit ZT= (S 2σ/κ)T, where S is the Seebeck coefficient, σ the electrical conductivity and κ the thermal conductivity; with larger values of ZT corresponding to higher energy conversion efficiency. The two main parameters are proportional to each other, i.e. increasing the electrical conductivity results in increase of thermal conductivity. Hence it is a main challenge in the field of thermoelectrics to increase the electrical conductivity and to keep the low thermal conductivity. Scope of the proposed PhD project is the use of 3D Topological Insulators (TIs) as TEs. The special topology of these surface states means that there is no dissipation from electrical conduction through these channels whilst an increased number of both extended and point defects can drastically decrease the thermal conductivity. Hence these materials have the potential for the highest thermoelectric figure of merit of any material! In particular, this project will explore the role of their dissipation-less surfaces and topologically protected states at structural defects, with respect to their electronic and thermal transport properties. The project will involve the Tis growth at the Department of Physics at York, structural and electronic structure characterization with state of the art electron microscopy at the York-JEOL Nanocentre and SuperSTEM facilities and thermoelectric transport property measurements at the University of Manchester. This project will be great opportunity to demonstrate how fundamental research translates into real world solutions.