New liquid crystalline solution processable organic semiconductors and their performance in field effect transistors

Shkunov, M; Zhang, WM; Graham, D; Sparrowe, D; Heeney, M; Giles, M; Tierney, S; Bailey, C; McCulloch, I; Kreouzis, T

ORGANIC FIELD EFFECT TRANSISTORS II

2003

New polymerisable liquid crystalline organic semiconductors based on small molecule "reactive mesogens" are reported. These molecules, comprising p-conjugated cores with reactive endgroups, were designed, synthesised then solution processed into thin films. The mesogenic morphology was attained thermally and fixed through a post fabrication photopolymerisation reaction. Thermal, optical and electrical properties of these thin films were characterised to reveal details of morphology and molecular orientation. Both bulk (time-of-flight) and surface (field-effect) charge carrier mobilities were measured. The relationship between molecular structure, corresponding macrostructure processability and charge mobility is discussed. Fabrication and characterisation of field-effect transistors based on reactive mesogens are presented and discussed.