We report low temperature processed, low voltage operable n-channel organic field effect transistors (OFETs) using N,N'-Diocty1-3,4,9,10-perylenedicarboximide (PTCDI-C-8) organic semiconductor and poly (methylmethacrylate) (PMMA)/lithium fluoride (LiF) bilayer gate dielectric. We have studied the role of LiF buffer dielectric in effectively reducing the gate leakage through the device and thus obtaining superior performance in contrast to the single layer PMMA dielectric devices. The bilayer OFET devices had a low threshold voltage (V-t) of the order of 53 V. The typical values of saturation electron mobility (mu(s)), on/off ratio and inverse sub-threshold slope (S) for the range of devices made were estimated to be 2.8 x 10(-3) cm(2)/V s, 385, and 3.8 V/decade respectively. Our work thus provides a potential substitution for much complicated process of chemically crosslinking PMMA to achieve low leakage, high capacitance, and thus low operating voltage OFETs. (C) 2015 Elsevier Ltd. All rights reserved.