Photocurrent amplification of graphene intercalation with titanium dioxide in photoelectrochemical devices

As a promising solution to renewable energy source and self-powered sensing, photoelectrochemical (PEC) devices have attracted extensive research interests in recent years. In this work, a PEC device is developed by sequentially incorporating graphene and titanium dioxide (TiO₂) nanoparticle multilayers using layer-by-layer (LbL) self-assembly. As a mediation layer between the TiO₂ nanoparticle film and the gold substrate, compact graphene layer effectively facilitates the separation of electrons and holes, yielding significantly higher quantum efficiency. Dependent on the concentration of TiO₂ nanoparticle suspension, graphene intercalation layer enhances more than one order of magnitude photocurrent amplification under UV light illumination, ranging from 12 to 43 times. The low-cost and facile fabrication processes to generate a stable photocurrent output of this device implies its promising potential applications to sensing and energy harvesting.