| 초록 |
Organic semiconductors are the subject of intense research, because they have great potential in applications such as organic light emitting diodes (OLEDs),organic thin film transistors (OTFTs), and organic photovoltaic cells (OPVs). Interests in these devices has steadily increased in both academic and industrial institutions. The technological interest of organic thin film transistors resides in their potential to promote low-cost, large areas, and flexible electronic circuitry. The most important criteria for a commercial application of OTFTs are high charge carrier mobility and high on-off current ratio. Among the rest, the facts important for obtaining high mobilities are the use of organic molecules with high structural order and an extended system as active layer. Many of the organic semiconductors used for the fabrication of the p-channel in OTFTs have been derived from thiophene-based -conjugated systems, oligothiophene, carbon-sulfur fused rings, acenes, phthalocyanines, polythiophene,and polythienylenevinylenes.Especially, the acene and oligothiophene derivatives represent two of the most heavily studied series of compounds for use as organic semiconductors. As opposed to polymer based materials, the advantages of using these small molecules include the ease of purification and the ability to precisely control their molecular structures and properties such as solubility, ionization potential (IP), and HOMO LUMO gap. However, even subtle structural modifications of these small molecules can change the molecular ordering in the thin-film state, resulting in drastic effects on the performance of the FET |
