Super-Assembled Lamellar Conductive Heterochannels with Optical-Electrical Coupling Sensitivity for Smart Ion...

Artificial nanofluidic devices inspired bylight-driven ion transport in biological systems, leveraging the photoelectric effect, have attracted extensive attention for their potential in signal transduction and smart ion transport applications. However, effective separation of photogenerated carriers in traditional p-n junction interface can be hindered by energy band structure of different semiconductor materials. Here, we present a novel approach using conductive polypyrrole (PPy) to modify graphene oxide (GO), creating polypyrrole-graphene oxide (PyGO) functional lamellar conductive nanochannels with tailored channel-sized gradients and inherent optical-electrical coupling sensitivity via a facile super-assembly strategy. This design facilitates the PyGO own conductive lamellar channels and efficient separation of photogenerated carriers, resulting in significantly enhanced selective ion transport behavior. Coupling the conductivity and photosensitivity of PPy contributes to a peak power density of 14.1 W m^-2 under a salinity differential of 0.5/0.01 M NaCl, which is 35.6 % higher than that under dark conditions. Additionally, combing the salinity gradients with optical-electrical coupling sensitivity of the nanofludic devices, we demonstrate the application of PyGO in a real-time detection device for monitoring ion concentrations in nutrient solutions, paving the way for smart irrigation systems in agriculture. This work presents a novel and effective strategy for light-driven ion transport with potential applications in energy conversion and beyond.