A simple method to prepare self-assembled organic-organic heterobilayers on metal substrates

We demonstrate a self-assembly based simple method to prepare organic-organic heterobilayers on a metal substrate. By either sequential- or co-deposition of para-sexiphenyl (p-6P) and pentacene molecules onto the Cu(110) surface in ultrahigh vacuum, p-6P/pentacene/Cu(110) heterobilayer is synthesized at room temperature. The layer sequence of the heterostructure is independent of the growth scenario indicating the p-6P/pentacene/Cu(110) is a self-assembled structure with lowest energy. Besides, the bilayer shows a very high orientational ordering and is thermally stable up to 430K.