| 초록 |
Four new quaterthiophene derivatives with end-groups composed of dicyclohexyl ethyl (DCE4T), dicyclohexyl butyl (DCB4T), cyclohexyl ethyl (CE4T), and cyclohexyl butyl (CB4T) were designed. UV-vis absorption measurements showed that the quaterthiophene derivatives with asymmetrically substituted cyclohexyl end-groups preferred H-type aggregation whereas those with symmetrically substituted cyclohexyl end-groups preferred J-type aggregation. The field-effect mobilities of devices that incorporated the asymmetrical molecules, CE4T and CB4T, were quite high, above 102cm2/(Vs) whereas the field-effect mobilities of devices that incorporated symmetrical molecules, DCE4T and DCB4T, were poor, below 104cm2/(Vs). More importantly, H-aggregation within the thin film provided stable crystalline morphologies in the spin-coated films, and, thus, thin film transistors using cyclohexylated quaterthiophenes yielded highly reproducible transistor performances. |
