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

摘要

New polymerisable liquid crystalline organic semiconductors based on small molecule "reactive mesogens" are reported. These molecules, comprising π-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.