Improvement charge injection in P-type polymer field-effect transistors with low-cost molybdenum electrodes through dodecanoic acid self assembled monolayer

ABSTRACT

Most of the merit of organic thin film transistors (OTFTs) is that they can be manufactured using cost effective processes. However, expensive gold (Au) electrodes have usually been used as a source/drain (S/D), due to their benign energy level matching, high air stability, and easy patternability. In this article, we report a simple method for improving the charge injection from a low cost molybdenum (Mo) electrode to organic semiconductors in OTFTs by incorporating a dodecanoic acid (DA)–based self-assembled monolayer (SAM). The OTFT performance is remarkably improved when compared to the devices with a pristine Au electrode. The hole carrier mobilities (hole μ_FET) were ∼0.13 (rr-P3HT), ∼0.55 (PC12TV12T) and ∼0.72 (P2100) cm²/V·sec.

KEYWORDS:

• Charge injection
• conjugated polymers
• organic field effect transistors
• self-assembled monolayer

Funding

This work was supported by a National Research Foundation of Korea (NRF) grant, funded by the Korean Government (MSIP) (NRF-2014R1A2A2A01007159).