Synthesis and characterization of solution-processable organic semiconducting materials for organic thin-film transistors

Abstract

The identification of new organic semiconducting molecules has been a crucial factor driving improvements in organic thin-film transistors (OTFTs). Recently there has been increased interest in the stability and processability of OTFT devices, in addition to the conventional focus on device performances. Organic molecules soluble in organic solvents are promising materials for inexpensive device fabrication since they can be processed by simple solution techniques. To make new solution-processable organic semiconductors showing good stability and processability, we developed a core molecule containing soluble anthracene derivatives -TIPSAnt. We investigated potentialities of TIPSAnt as the core molecule and applied it to both small molecular systems and polymeric systems. Firstly, we developed TIPSAnt and investigated the potentialities as solution-processable semiconductors. Triisopropylsilylethynyl derivatives were added at the 9,10-positions of anthracene for the solubility and crystallinity. The soluble anthracene core (TIPSAnt) is a potential precursor for the synthesis of novel semiconducting materials. Hexyl thiophene and phenylenevinylene derivatives were firstly introduced to TIPSAnt. TIPSAntHT and TIPSAntPV show the promising properties and potentialities for solution-processable semiconductors. Therefore, we propose TIPSAnt as a precursor of a new class of semiconducting molecules with desirable properties: solubility, high crystallinity in single crystal and thin film form, solution-technique processability, good optical properties, and electrochemical stability. Secondly, we applied TIPSAnt into small molecular systems. Three new small molecules based on TIPSAnts containing thiophene, benzothiophene, and phenyl thiophene as end-cappers were synthesized. We revealed structural relationships of the molecules with TFT performances based on crystalline properties as well as thermal, optical, electrochemical, and morphological properties of these...