Suppressing molecular vibrations in organic semiconductors by inducing strain

• Published in: Nature communications 2016-04, Vol.7 (1), p.11156-11156, Article 11156
• Main Authors: Kubo, Takayoshi, Häusermann, Roger, Tsurumi, Junto, Soeda, Junshi, Okada, Yugo, Yamashita, Yu, Akamatsu, Norihisa, Shishido, Atsushi, Mitsui, Chikahiko, Okamoto, Toshihiro, Yanagisawa, Susumu, Matsui, Hiroyuki, Takeya, Jun
• Format: Article
• Language: English
• Subjects: 639/301/119/1000; 639/301/119/998; 639/301/923/3931; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms11156

Organic molecular semiconductors are solution processable, enabling the growth of large-area single-crystal semiconductors. Improving the performance of organic semiconductor devices by increasing the charge mobility is an ongoing quest, which calls for novel molecular and material design, and improved processing conditions. Here we show a method to increase the charge mobility in organic single-crystal field-effect transistors, by taking advantage of the inherent softness of organic semiconductors. We compress the crystal lattice uniaxially by bending the flexible devices, leading to an improved charge transport. The mobility increases from 9.7 to 16.5 cm 2  V −1  s −1 by 70% under 3% strain. In-depth analysis indicates that compressing the crystal structure directly restricts the vibration of the molecules, thus suppresses dynamic disorder, a unique mechanism in organic semiconductors. Since strain can be easily induced during the fabrication process, we expect our method to be exploited to build high-performance organic devices. The mobility of organic semiconductors can be tuned by modifying their chemical composition or crystalline properties. Here, the authors show that bending organic single crystals increases their field effect transistor mobility due to restrained molecular vibrations and subsequently reduced dynamic disorder.