ABSTRACTMost 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 μFET) were ∼0.13 (rr-P3HT), ∼0.55 (PC12TV12T) and ∼0.72 (P2100) cm2/V·sec.