Capacitor or Memristor: Janus Behavior of Polyoxometalates

Polyoxometalates (POMs) have attracted much attention in the development of data storage devices with alternative nanophysics. Numerous studies can be found on their integration into charge-based and resistive types of memory. However, the question of whether the POM behaves as a molecular capacitor or a molecular memristor remains largely unexplored. In this Article, we clarify this fundamental question by placing the individual electronic properties of POMs in the context of their chemical and technical environment. By control of the charge stabilization of reduced POMs through chemical functionalization, choice of countercations, surface properties, and intermolecular interactions, various physical switching mechanisms can be realized, demonstrating the remarkable uniqueness of these molecular oxides.