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Projects: Projects for Investigator
Reference Number	EP/P000525/1
Title	Origin of the Strong Induced Chiroptical Effect in Semiconducting Polymer/Helicene Blends
Status	Completed
Energy Categories	Energy Efficiency(Residential and commercial) 10%; Not Energy Related 90%;
Research Types	Basic and strategic applied research 100%
Science and Technology Fields	PHYSICAL SCIENCES AND MATHEMATICS (Chemistry) 50%; PHYSICAL SCIENCES AND MATHEMATICS (Physics) 50%;
UKERC Cross Cutting Characterisation	Not Cross-cutting 100%
Principal Investigator	Dr AJ Campbell No email address given Department of Physics (the Blackett Laboratory) Imperial College London
Award Type	Standard
Funding Source	EPSRC
Start Date	01 January 2017
End Date	31 December 2019
Duration	36 months
Total Grant Value	£424,709
Industrial Sectors	Electronics
Region	London
Programme	NC : Physical Sciences
Investigators	Principal Investigator	Dr AJ Campbell , Department of Physics (the Blackett Laboratory), Imperial College London (99.999%)
	Other Investigator	Dr MJ Fuchter , Chemistry, Imperial College London (0.001%)
	Industrial Collaborator	Project Contact , Cambridge Display Technology Ltd (0.000%)
Web Site
Objectives
Abstract	Organic semiconductors form the basis of optoelectronic devices such as organic light emitting diodes, organic solar cells and organic field-effect transistors. These devices are very thin, lightweight and flexible, and can be fabricated over large areas from solution by simple printing techniques under ambient conditions.One of the most developed areas in organic electronics is that of organic light emitting diode (OLED) based displays for mobile phones, tablets and televisions; these make a major contribution to a multi-billion dollar global industry. We have recently discovered a method to produce an OLED that emits circularly-polarized light. This very simple method involves blending a conventional light emitting semiconducting polymer with a helically shaped molecule known as a helicene. The helically shaped molecule somehow causes the spaghetti-like polymer chains to change conformation, resulting in the polymer emitting circularly-polarized (CP) light. Such a CP emitting OLED has application in conventional OLED displays, 3-D OLED displays, and as backlights in liquid-crystal displays. For example, to improve contrast, most displays contain a top circularly-polarized filter to remove back-reflected light. A CP emitting OLED would allow all the emitted light to pass through this filter, potentially doubling the energy efficiency of the display. This would reduce global energy consumption, increase battery life of portable products, and increase display lifetime. Other potential applications of CP emitting OLEDs include protein detection in biomedicine, optical spintronics, optical quantum computing, and conventional and quantum optical telecommunication.Despite the success of our simple and novel method, we do not understand the principle of how mixing the polymer with the helicene results in a change in the polymers structure allowing it to emit CP light. The purpose of this grant is to actually understand this process, finding out exactly how the polymers structure is affected by blending with the helicene. We will investigate how this phase forms when the mixture is heated and cooled; how this changes with polymer chain length and polymer/helicene ratio; how we can generate this phase by solution processing using different solvents and different annealing treatments; whether a helical liquid crystal phase can form; and how these factors affect thin film morphology and microstructure. We will also investigate the CP light emission process, looking at factors such as whether CP light absorbed by the helicene can result in CP emission from the polymer. The particular semiconducting polymer concerned (F8BT) is known to transport both electrons and holes; we will investigate charge transport in the novel helical phase. We will take all the processing knowledge and create an optimized CP-OLED, with a high CP light output, brightness and efficiency. We will also investigate other similar semiconducting polymers which emit CP light when blendedwith helicenes, looking at their structural, spectroscopic and electronic properties.This project involves an ideal synergy between teams in the Departments of Physics and Chemistry at Imperial College London and in the Department of Materials Science and Engineering at the University of Sheffield, the former covering spectroscopic, electronic and device measurements and the latter covering structural and morphological measurements and modeling. It will also involve a partnership with Cambridge Display Technology (UK), supplying high performance polymers and expertise, and enabling rapid transfer of the technology towards the marketplace.
Publications	(none)
Final Report	(none)
Added to Database	01/02/19