Spectroscopy of Organic Semiconductors: From Solar Cells to Polaritons

Dr Jenny Clark, University of Sheffield

Part of the Physical Seminar Series Abstract To understand the electronic physics of organic semiconductors (i.e. pi-conjugated molecules in the solid-state), I use a range of spectroscopic techniques. In this talk, I will concentrate on describing our current understanding of a process known as ‘singlet exciton fission’ that occurs in some organic semiconductor materials. In singlet exciton fission, the photoexcited singlet (spin-0) exciton spontaneously splits into two triplet (spin-1) excitons. This two-for-one process offers the possibility of beating the Shockley Quiesser limit in solar cells, overcoming thermalisation. Singlet fission can be very rapid (100fs-100ps) and is generally described as proceeding through an intermediate triplet-pair state. The nature of this intermediate state has been the subject of much debate. In this talk, I will discuss our recent work on singlet fission materials with particular emphasis on the nature of the intermediate triplet-pair state. I will conclude by describing some very recent work demonstrating how photon-exciton interactions in organic exciton microcavities can be used to squeeze light out of the triplet pair states by coupling them to the cavity's photon mode.
Virtual Open Days
Be Curious 2020
Dr Edward Emmett, Syngenta