Modification of gold source and drain electrodes by self-assembled monolayer in staggered n- and p-channel organic thin film transistors

We report on the effect of the deposition of self-assembled monolayers (SAMs) on the source and drain electrodes on the contact resistance and mobility in organic thin film transistors (OTFTs). Ultraviolet photoelectron spectroscopy (UPS) shows a variation of the work function of the electrodes depending on the SAM. OTFTs were fabricated with solution processible Polyera ActivInk™ N1400, TIPS-pentacene and TFB, giving access to both polarities of transistors and to both crystalline and amorphous materials. The transfer line method (TLM) was used to separately estimate the contact resistance and mobility. A clear correlation is found between the work function of the modified electrodes and the corresponding contact resistance. The effect on mobility is more puzzling, and tentatively attributed to morphological effects.