Resistive memory switching of transition-metal complexes controlled by ligand design

Transition-metal complexes (TMCs) have recently attracted considerable scientific interest for resistive memory switching. The interplay between metal ions and ligand endows TMCs with rich and tunable electrochemical and photophysical properties, making them beneficial for the formation of electrical bi- or multistates in resistive memory devices. This review summarizes the applications of TMCs in resistive memory switching. Following the simple introduction of the basic concept and switching mechanism of resistive memory devices, the recent progress on the applications of ferrocene derivatives, polyazine metal complexes and metallopolymers, alkynyl metal complexes, and porphyrin or phthalocyanine metal complexes are discussed, with an emphasis on the modulation or control of switching properties by ligand design.