Microscopic observation of highly mobile charge carriers in organic transistors of semicrystalline conducting polymers

作者：Kawamura Shinya; Wakamatsu Ayato; Kuroda Shin-ichi; Takenobu Taishi; Tanaka Hisaaki^*

来源：Japanese Journal of Applied Physics, 2018, 57(2): 02CA04.

DOI：10.7567/JJAP.57.02CA04

Charge carrier dynamics in organic field-effect transistors (OFETs) of semicrystalline conducting polymers poly(2,5-bis(3-hexadecylthiophene-2-yl)thieno[3,2-b] thiophene) (PBTTT) and poly(3-hexylthiophene) (P3HT) have been investigated down to 4 K by field-induced electron spin resonance (FI-ESR) spectroscopy. The highly mobile nature of charge carriers within the ordered regions of the polymers has been clarified from the observation of the motional narrowing effect of the ESR spectra even below 30 K, where device operation cannot be observed presumably owing to the effect of domain boundaries. The activation energy of carrier motion observed by ESR has been determined as 17meV for PBTTT and 13meV for P3HT, which are an order of magnitude smaller than that of FET mobility (> 110 meV) obtained for the same devices. These results demonstrate that the intrinsic carrier mobility within the ordered region is much higher than that expected from the macroscopic transport measurements in the semicrystalline polymers.

• 出版日期2018-2