Rational design of a Ru(II) complex with a donor-acceptor-donor structure for organic resistive memory devices.

A novel Ru(II) complex with a donor-acceptor-donor (D-A-D) ligand was designed and synthesized to prepare organic memory devices. The fabricated Ru(II) complex-based devices exhibited obvious bipolar resistance switching behavior with a low switching voltage (∼1.13 V) and a large ON/OFF ratio (10 5 ). The dominant switching mechanism can be explained by the distinct charge-transfer states endowed by the interaction between metals and ligands, which is verified by density functional theory (DFT) calculations. Excitingly, the device displays a much lower switching voltage than most of the previously reported metal complex based memory devices due to the intense intramolecular charge transfer caused by the strong built-in electric field in D-A systems. This work not only reveals the potential of the Ru(II) complex in resistive switching devices, but also provides new inspiration to manipulate the switching voltage at the molecular level.