Singlet fission in polyenes

Completed

Renewable Energy Sources(Solar Energy, Photovoltaics)
Not Energy Related

Basic and strategic applied research

PHYSICAL SCIENCES AND MATHEMATICS (Physics)

Not Cross-cutting

Dr J Clark
Physics and Astronomy
University of Sheffield

Standard

EPSRC

01 May 2016

30 April 2017

12 months

£99,445

Optics; photonics & lasers

Yorkshire & Humberside

NC : Physical Sciences

Dr J Clark, Physics and Astronomy, University of Sheffield

Project Contact, Imperial College London
Project Contact, University Centre Somerset
Project Contact, Argyll College
Project Contact, Bury College
Project Contact, University of Oxford
Project Contact, University of Cambridge

In current solar cells much of the UV and blue light absorbed is lost as heat, as the energy of the absorbed photon is much higher than the bandgap of the semiconductor material, and therefore the collected electronic energy. One mechanism for harvesting all of the absorbed photon energy is to exploit the 'singlet exciton fission' process which occurs in some organic semiconductors. Singlet fission is a process whereby the primary excited state (singlet exciton) can split into two distinct triplet excitons which can both be harvested. In this way, one absorbed photon creates two collected charges, producing a solar cell with up to 200% quantum efficiency.Singlet fission in polyenes (linear conjugated carbon chains) occurs when there is enough space for two triplet excitons to sit near each other: either on a very long polymer chain, or on two closely spaced neighbouring molecules. Polyenes demonstrate strong photoabsorption in UV-visible region, are solution-processable and demonstrate very efficient and robust singlet fission. They are therefore excellent candidates for singlet fission solar cells. To exploit the singlet fission mechanism and the polyene class of materials, we need better understanding of how to describe singlet fission in polyenes and how to control it through material design. In addition, we urgently need to demonstrate whether the triplet excitons created through singlet fission can be efficiently ionised to create charges. In this project, we will answer these questions using a combination of cutting-edge time-resolved spectroscopic techniques, model samples and high-level theory

12/02/19