Multilayer Engineering of Polyaniline and Reduced Graphene Oxide Thin Films on a Plastic Substrate for Flexible Optoelectronic Applications Using NIR

This article describes the photoconductive properties of a multilayer uniform ultrathin film comprising alternating polyaniline (PANi) and reduced graphene oxide (RGO) layers, fabricated on a poly(ethylene terephthalate) (PET) sheet. The fabrication of the two electron-rich layers on the PET substrate is successfully completed using a layer-by-layer (LBL) deposition technique under mild conditions and HI/H2O vapor treatment at 100°C. The photocurrent under illumination of >300 nm light exhibits 80 µA compared with that of obtained in the dark. However, it decreases to 75 µA under >460 nm light illumination and further increases to 80 µA under >600 nm light illumination (0.64 mW) at an applied voltage of 1.0 V. The PET sheets coated with (PANi/RGO)20 films (d = 46.3 nm) exhibits a photoresponsivity of 125 mA/W at an illunination intensity of 0.64 mW using red light (> 600 nm). The extraordinary optoelectronic characteristics of the (PANi/RGO) films are ascribed to the charge transfer complex formation of the two PANi and RGO layer components and also to the structural uniformity of the LBL-assembled optoelectronic thin films, which tended to favor the rapid interfacial charge transfer to the electrodes.