[12a-N205-1~12] 12.4 Organic light-emitting devices and organic transistors

▲ [12a-N205-9] Ambipolar transistor properties of segregated charge-transfer complexes

〇(M1)NikhilRao Mallela¹, Tadashi Kawamoto¹, Takehiko Mori¹ (1.Tokyo Institute of Technology)

Keywords:Charge Transfer complexes, Organic Semiconductors, Organic Electronics

Charge-transfer complexes are composed of charge-donating (D) and charge-accepting (A) molecules. While the parent compounds are unipolar semiconductors, charge-transfer complexes are expected to show ambipolar transistor properties. We have previously reported that mixed stacked complexes are semiconducting, but show field-effect transistor properties. Even ionic charge-transfer complexes show transistor properties in the thin films. However, in general, segregated complexes are too highly conducting to show transistor properties. Here we report transistor properties of segregated 1,6-diaminopyrene (DAP) complexes of TCNQ and dimethyl-TCNQ. The segregated complex has a completely ionic ground state with the charge-transfer degree close to unity and thus behaves as a Mott-type insulator. Despite the high conductivity, after subtracting the bulk current of ~6 mA, the thin-film transistors show balanced ambipolar transistor properties, which are maintained down to 200 K. The newly prepared DMTCNQ complex exhibits similar ambipolar transistor properties.