Electronic structure of energy materials

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Electronic structure of materials is fundamental to renewable energy. For example, the band gap and alignment of valence/conduction bands govern photovoltaic performance. There are only a handful of experimental techniques that measure electronic structure, such as scanning tunnelling spectroscopy, angle resolved photoemission spectroscopy and electron-positron annihilation. These have several drawbacks, such as the need for high quality single crystal samples, radioactive sources and limited spatial resolution. Developing new energy materials requires versatile characterisation methods that are applicable in both thin-film and polycrystalline material. My group has recently developed electron Compton scattering in the TEM (Talmantaite et al, J Microscopy 2019, Mendis and Talmantaite, Microsc. Microanal, in press). This measures the momentum density distribution of electronic states. We have successfully used Compton scattering to analyse band gap transitions in 2D materials and metal-insulator phase changes. This project will exploit Compton scattering and the superior TEM spatial resolution to analyse some fundamental electronic structure problems in energy materials, such as band gap grading and electronic structure of interfaces and grain boundaries in PV, as well as quantum wells in LEDs. This is a unique opportunity for a student to pioneer a new set of analytical techniques that has widespread use. The student will gain skills in advanced electron microscopy and DFT simulations, and be exposed to several different energy materials and devices (PV, LED) provided by external collaborators (Liverpool and Cambridge). Due to the versatility of the method there is also scope to work on other ReNU projects, e.g. battery materials.