Enhanced pentacene grain growth on the smectic A phase of ionic liquid crystal buffer layers

Abstract We demonstrate the growth of large-grain pentacene films using the smectic A (SmA) phase of [C 16 mim][PF 6 ] ionic liquid crystal (ILC) as a buffer layer. When deposited on the fluidic SmA phase, pentacene forms large, faceted grains with lateral sizes exceeding 20 μm. This result is attributed to the enhanced surface diffusion of pentacene molecules. In contrast, pentacene films deposited onto the crystalline phase of the ILC and the smectic LC phases of other LCs, respectively, all exhibit significantly smaller grains, highlighting the unexpected role specific to use of the SmA phase of the ILC as the buffer layer.