Fabrication of high-quality flexible transparent conductive thin films with a Nb2O5/AgNWs/Nb2O5 sandwich structure

Different sandwich structures of flexible transparent conductive thin film (TCFs) composed of Nb2O5 layers and Ag nanowires (AgNWs) have been prepared onto flexible polyethylene terephthalate (PET) substrate at room temperature to develop an indium-free TCF. The AgNWs are synthesized by a modified polyol method and inserted into the Nb2O5 layers that are prepared by radio frequency magnetron sputtering. The optical and electrical properties can be modified by changing the number of spin-coating cycle of AgNW suspension. At optimized condition, we achieve a flexible Nb2O5/AgNWs/Nb2O5 sandwich thin film with a low sheet resistance of 9.61 Ω/square and a high optical transmittance of 84.3%. Meanwhile, the resistance remains nearly constant after 30 tape tests, suggesting a strong adhesion to the PET substrate. The sandwich thin films show high long-term stability to oxidation, humid heat, and chemicals compared with that of AgNW networks, which can be attributed to the effective covering of Nb2O5 layer on the AgNWs. In addition, the Nb2O5/AgNWs/Nb2O5 sandwich thin films show good stability after repeated bending. This Nb2O5/AgNWs/Nb2O5 sandwich thin film can therefore serve as a high-performance transparent conductive electrode for numerous flexible electronic devices.