Plasmonic Hot Hole Generation by Interband Transition in Gold-Polyaniline

Studies on hot carrier science and technology associated with various types of nanostructures are dominating today's nanotechnology research. Here we report a novel synthesis of polyaniline-gold (PAni-Au) nanocomposite thin films with gold nanostructures (AuNs) of desired shape and size uniformly incorporated in the polymer matrix. According to shape as well as size variation of AuNs, two tunable plasmonic UV-Visible absorption bands are observed in each of the nanocomposites. Plasmonic devices are fabricated using PAni-Au nanocomposite having different UV-Visible plasmon absorption bands. However, all the devices show strong photoelectrical responses in the blue region (400-500 nm) of the visible spectrum. The d-band to sp-band (d-sp) transition of electrons in AuNs produces hot holes that are the only carriers in the material responsible for photocurrent generation in the device. This work provides an experimental evidence of novel plasmonic hot hole generation process that was still a prediction.