Abstract
A vacuum-free solution processed hybrid dielectric composed of an anthryl-alkyl-phosphonic acid (pi-sigma-PA) self-assembled monolayer on an amorphous sol-gel processed hafnium oxide (HfOx) is demonstrated for low-voltage organic thin film transistors (OTFTs) on plastic substrates. The pi-sigma-PA/HfOx hybrid dielectric provides high capacitance (0.54 mu F cm(-2)) and low leakage current (2 x 10(-8) A cm(-2)), and has a chemically and electrically compatible dielectric interface for evaporated and solution processed acene semiconductors. The utility of this dielectric is demonstrated by fabricating pentacene and 6,13-bis(triisopropyl-silylethynyl) pentacene (TIPS-PEN) based OTFTs with operating voltages under 2 V, subthreshold slopes as low as 100 mV dec(-1), and average mobilities of 0.32 cm(2)V(-1)s(-1) and 0.38 cm(2)V(-1)s(-1), for pentacene and TIPS-PEN, respectively.