School of Natural and Environmental Sciences

Event items

Spectroscopy of organic semiconductors and how one photon can produce two excited-states

Chemistry Seminar Series - Dr Jenny Clark, University of Sheffield

Date/Time: Tuesday 13 November 2018, 14:00 - 15:00

Venue: Room 2.76, Bedson Building

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.