Conductance switching in TiO₂ nanorods is a redox-driven process: evidence from photovoltaic parameters

Abstract

We study the effect of conductance switching of TiO₂ nanorods on photovoltaic parameters. We fabricate devices with varied concentration of TiO₂ nanorods in a poly(3-hexylthiophene) (P3HT) matrix with two electrodes. From the change in photovoltaic parameters upon switching, we have inferred that the conductance switching process of TiO₂ nanorods is a redox-driven one. The electroreduction process changes the electronic energy levels of TiO₂ that in turn modify the band diagram of P3HT:TiO₂ devices. Under illumination, the open-circuit voltage of the device has hence become a parameter to probe the conducting state of TiO₂ nanorods. We show that the open-circuit voltage can act as a probe parameter to evidence read-only and random-access memory applications.