[7p-A203-1~19] 12.4 Organic light-emitting devices and organic transistors

[7p-A203-5] ESR Observations of Charge Transport across Domain Boundaries in TFTs of Donor-Acceptor-Type Conducting Polymers

〇Hisaaki Tanaka¹, Ayato Wakamatsu¹, Taishi Takenobu¹, Yukihiro Shimoi², Shin-ichi Kuroda^1,3 (1.Nagoya Univ., 2.CD-FMat, AIST, 3.TPCRI)

Keywords:donor-acceptor polymers, electron spin resonance

Donor-acceptor (DA) type conjugated polymers have attracted much research interest as the materials for high mobility organic TFTs. In these polymer thin films, rigid polymer chains are suggested to act as tie molecules between the ordered domains, which accelerate inter-domain carrier hopping, resulting in highly efficient charge transport within the film. However, there have been no researches which directly observe the inter-domain carrier hopping in these DA polymers. In this study, we adopted the ESR spectroscopy to obtain microscopic information of carrier dynamics in TFTs of DA polymers. We successfully observed a “motional narrowing” of the ESR signal associating with the inter-domain carrier hopping even at low temperatures. In contrast, TFTs using conventional semicrystalline polymers exhibited no signature of inter-domain carrier hopping at low temperatures. These results demonstrate that the DA polymers indeed exhibit a highly efficient charge transport across the domain boundaries, which is an origin of the reported high mobilities in these polymer TFTs.