Conductance Switching in TiO2 Nanorods is a Redox-Driven Process: Evidence from Photovoltaic Parameters

We study the effect of conductance switching of TiO2 nanorods on photovoltaic parameters. We fabricate devices with varied concentrations 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.