Gate Controlled Molecular Switch Based on Picene/F4TCNQ Charge-Transfer Material

We show that the recently synthesized charge-transfer material picene/F4TCNQ can be used as a gate-voltage controlled molecular switch. The picene/F4TCNQ system is compared with the extensive characterized anthraquinone-based molecular system, which is known to exhibit large switching ratios due to quantum interference effects. In case of picene/F4TCNQ we find switching ratios larger by one order of magnitude. Further, our calculations reveal that the picene/F4TCNQ system resembles remarkable well the I-V characteristics of a classical diode. The reverse-bias current of this molecular diode can be increased two orders of magnitude by an external gate voltage. Based on density-functional theory calculations we show that the hybrid states formed by the picene/F4TCNQ system are playing the key role to determine the transport properties. We further conclude that the tuning of quantum transport properties through hybrid states is a general concept which opens a new route towards functional materials for molecular electronics.