Utilizing Carbon Nanotube Electrodes to Improve Charge Injection and Transport in Bis(trifluoromethyl)-dimethyl-rubrene Ambipolar Single Crystal Transistors
- 31 October 2013
- journal article
- Published by American Chemical Society (ACS) in ACS Nano
- Vol. 7 (11), 10245-10256
- https://doi.org/10.1021/nn4045694
Abstract
We have examined the significant enhancement of ambipolar charge injection and transport properties of bottom-contact single crystal field-effect transistors (SC-FETs) based on a new rubrene derivative, bis(trifluoromethyl)-dimethyl-rubrene (fm-rubrene), by employing carbon nanotube (CNT) electrodes. The fundamental challenge associated with fm-rubrene crystals is their deep-lying HOMO and LUMO energy levels, resulting in inefficient hole injection and suboptimal electron injection from conventional Au electrodes due to large Schottky barriers. Applying thin layers of CNT network at the charge injection interface of fm-rubrene crystals substantially reduces the contact resistance for both holes and electrons; consequently, benchmark ambipolar mobilities have been achieved, reaching 4.8 cm(2) V(-1) s(-1) for hole transport and 4.2 cm(2) V(-1) s(-1) for electron transport. We find that such improved injection efficiency in fm-rubrene is beneficial for ultimately unveiling its intrinsic charge transport properties so as to exceed those of its parent molecule, rubrene, in the current device architecture. Our studies suggest that CNT electrodes may provide a universal approach to ameliorate the charge injection obstacles in organic electronic devices regardless of charge carrier type, likely due to the electric field enhancement along the nanotube located at the crystal/electrode interface.Keywords
Funding Information
- Office of Naval Research (N00014-11-1-0690)
- Division of Materials Research (DMR-0819885)
- Japan Society for the Promotion of Science (23750209)
This publication has 63 references indexed in Scilit:
- A stable solution-processed polymer semiconductor with record high-mobility for printed transistorsScientific Reports, 2012
- Highly enhanced charge injection in thienoacene-based organic field-effect transistors with chemically doped contactApplied Physics Letters, 2012
- Extremely Bendable, High-Performance Integrated Circuits Using Semiconducting Carbon Nanotube Networks for Digital, Analog, and Radio-Frequency ApplicationsNano Letters, 2012
- Organic Electrical Double Layer Transistors Based on Rubrene Single Crystals: Examining Transport at High Surface Charge Densities above 1013 cm–2The Journal of Physical Chemistry C, 2011
- Making Contacts to n-Type Organic Transistors Using Carbon Nanotube ArraysACS Nano, 2010
- Photoemission measurement of extremely insulating materials: Capacitive photocurrent detection in photoelectron yield spectroscopyApplied Physics Letters, 2008
- Tunable Fröhlich polarons in organic single-crystal transistorsNature Materials, 2006
- Electrode-molecular semiconductor contacts: Work-function-dependent hole injection barriers versus Fermi-level pinningApplied Physics Letters, 2006
- Controlling Charge Injection in Organic Field-Effect Transistors Using Self-Assembled MonolayersNano Letters, 2006
- Work functions of individual single-walled carbon nanotubesApplied Physics Letters, 2004