DISCOTIC LIQUID CRYSTAL-BASED FIELD EFFECT TRANSISTORS

Lead Research Organisation: University of Leeds
Department Name: Centre for Molecular Nanoscience

Abstract

We seek proof of principle funding for a very short project the aim of which is test whether it is possible to fabricate a Discotic Liquid Crystal based organic field effect transistor of the type use in RF tags and electronic paper. The aim is to use a new method which we have discovered for aligning DLCs in a planar fashion with control over the azimuthal angle. This new method of aligning DLCs is the first for DLCs that one could reasonably imagine being used in the manufacture of ink-jet or contact printed OFETS. Since the last step in the fabrication would require us to deposit the source and drain electrodes onto the DLC film the order and directionality of the conduction within the film needs to be 'locked in' by polymerisation. As a result the first requirement of the project will be to create suitable reactive monomers. Assuming that this is succesful we would apply for follow-on funding to develop OFETS based on the a wider range of high-mobility ambipolar DLC semiconductors
 
Description We were the first group in the world to demonstrate that liquid crystals can act not only as media for the conduction of ions but also as electronic conductors: as organic semiconductors (Chemical Physics Letters, 1988, 152, 94). This area has greatly developed and we have recently acted as editors for a book on this topic. (Liquid Crystalline Semiconductors: Materials, Properties and Applications, Springer,Dordrecht, 2013). We continue to actively seek commercial applications. In this grant the idea was to use a new method for aligning liquid crystals to fabricate field effect transistors of the type used in printed electronic devices. We only partly solved that problem at the time but the work was continued by the post doc employed (Dan Tate) after he left us and he has eventually brought it to a successful conclusion (International Conference on Digital Printing Technologies. 2015-January: 181-187. 01 Jan 2015) Although the charge mobilities he obtained are disappointingly low ( by this route there is no commercial way forward) an alternative fabrication method has been developed by one of his co-workers (see section below) (NATURE COMMUNICATIONS, 6828, 2015) which is getting some commercial interest.
Exploitation Route Whereas the method of making LC FETs that Dan Tate investigated in his work on this award gave rather disappointingly low carrier mobilities (too low to be of commercial interest) a Japanese student (Hiroaki Iino) who was working in parallel with him has carried on working independently since his return to Japan. He has subsequently shown that such FETs can be made which reproducibly give mobilities ~16. These are being actively investigated for commercialization. (NATURE COMMUNICATIONS, 6828, 2015).
Sectors Electronics
 
Description Whereas the method of making LC FETs that Dan Tate investigated in his work on this award gave rather disappointingly low carrier mobilities (too low to be of commercial interest) a Japanese student (Hiroaki Iino) who was working in parallel with him has carried on working independently since his return to Japan. He has subsequently shown that such FETs can be made which reproducibly give mobilities ~16. These are being actively investigated for commercialization. (NATURE COMMUNICATIONS, 6828, 2015).
First Year Of Impact 2015
Sector Electronics
Impact Types Cultural,Economic