Electronic states and dynamics of charge carriers in high-mobility organic transistors

2015 Fiscal Year Final Research Report

• Project/Area Number: 25287073
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: Nagoya Industrial Science Research Institute (2015); Nagoya University
• Principal Investigator: KURODA SHIN-ICHI 公益財団法人名古屋産業科学研究所, その他部局等, 研究員 (20291403)
• Co-Investigator(Kenkyū-buntansha): TANAKA HISAAKI 名古屋大学, 大学院工学研究科, 助教 (50362273) ; SHIOMOI YUKIHIRO 産業技術総合研究所, その他部局等, 研究チーム長 (70357226)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 有機半導体 / 電界効果デバイス / 非線形素励起 / 電子スピン共鳴 / 理論計算

Outline of Final Research Achievements

Recently, high-mobility organic field-effect transistors (OFETs) based on new pi-conjugated molecules and polymers attract significant attention. In this study, we have employed electron spin resonance (ESR) spectroscopy in detecting the charge carriers with spins in OFETs to elucidate their dynamics and electronic states. ESR parameters such as g-values have been theoretically analyzed using density-functional (DFT) calculations. As a result, significantly small activation energy of ~10meV has been revealed in an alkylated small molecule with extended pi-core (C10-DNTT). In the case of typical semicrystalline polymer, PBTTT, high-density reversible doping using ionic-liquid-gated transistor structures has clearly indicated the change of electronic states from polarons with spins via spinless bipolarons to the onset of metallic state. These results demonstrate the high potential of high-mobility materials for device applications as well as for the development of new functionalities.

Free Research Field

磁気共鳴、有機固体