Ultrahigh mobility and efficient charge injection in monolayer organic thin-film transistors on boron nitride

Daowei He, Jingsi Qiao, Linglong Zhang, Junya Wang, Tu Lan, Jun Qian, Yun Li, Yi Shi, Yang Chai, Wei Lan, Luis K. Ono, Yabing Qi, Jian Bin Xu, Wei Ji, Xinran Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

90 Citations (Scopus)

Abstract

Organic thin-film transistors (OTFTs) with high mobility and low contact resistance have been actively pursued as building blocks for low-cost organic electronics. In conventional solution-processed or vacuum-deposited OTFTs, due to interfacial defects and traps, the organic film has to reach a certain thickness for efficient charge transport. Using an ultimate monolayer of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) molecules as an OTFT channel, we demonstrate remarkable electrical characteristics, including intrinsic hole mobility over 30 cm2/Vs, Ohmic contact with 100 W · cm resistance, and band-like transport down to 150 K. Compared to conventional OTFTs, the main advantage of a monolayer channel is the direct, nondisruptive contact between the charge transport layer and metal leads, a feature that is vital for achieving low contact resistance and current saturation voltage. On the other hand, bilayer and thicker C8-BTBT OTFTs exhibit strong Schottky contact and much higher contact resistance but can be improved by inserting a doped graphene buffer layer. Our results suggest that highly crystalline molecular monolayers are promising form factors to build high-performance OTFTs and investigate device physics. They also allow us to precisely model how the molecular packing changes the transport and contact properties.
Original languageEnglish
Article number1701186
JournalScience advances
Volume3
Issue number9
DOIs
Publication statusPublished - 1 Jan 2017

ASJC Scopus subject areas

  • Medicine(all)

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