Physics Seminars
Electron Spectroscopy and Nanoscopy for optoelectronic nanomaterials and quantum materials
Speaker: Dr Giorgio Divitini (Istituto Italiano di Tecnologia, Italy)
Date: Wednesday 27 March 2024
Time: 15:00
Venue: Queens Building N3.28
Electron microscopy is a versatile tool for the characterisation of nanomaterials. Specifically, in our current projects, we extensively characterise nanocrystals for optoelectronics, including both conventional QDs (InAs and core-shell structures) and emerging materials (halide perovskites). In our materials discovery projects, we also investigate how heterostructures can be engineered between a perovskite component and a chalcohalide, designing epitaxial interfaces and controlling local strain. To this end we employ a variety of techniques implemented in a state-of-the-art Transmission Electron Microscope (TEM), including atomic resolution imaging and spectroscopy (STEM-EDX, STEM-EELS). By exploiting novel imaging methods, we can extract information from samples with a minimal electron dose, preventing the onset of beam damage. We also study 2D materials (2D perovskites, MXenes) to understand local chemical and crystallographic structure with nm-scale resolution, combining spectroscopy in the TEM with cathodoluminescence in the SEM. In this seminar our approaches will be showcased for a selection of materials and devices for optoelectronics. Key publications: (1) Doherty T.A.S., et al., Performance-limiting nanoscale trap clusters at grain junctions in halide perovskites Nature, 580, 7803, 360-366 (2020). (2) Tian T., et al., A sol-gel monolithic metal-organic framework with enhanced methane uptake, Nature Materials, 17, 2, 174-179 (2018). (3) Abdi-Jalebi M., et al., Maximizing and stabilizing luminescence from halide perovskites with potassium passivation Nature, 555, 7697, 497-501 (2018). (4) Divitini G., Cacovich S., Matteocci F., Cina L., Di Carlo A., Ducati C. In situ observation of heat-induced degradation of perovskite solar cells, Nature Energy, 1,1 (2016).