Ionic Diode Based on an Asymmetric‐Shaped Carbon Black Nanoparticle Membrane

Abstract Bioinspired ionic diodes are widely explored to mimic the controllable ion transport of biological ion channels. However, due to their vertical structures, the integration of conventional ionic diodes into complex ionic circuits is still a challenge. Here, a horizontal ionic diode is developed based on an asymmetric nanochannel network membrane (NCNM) constructed from carbon black nanoparticles. The rectification of ionic current is achieved through the asymmetric concentration polarization of ions at two ends of the asymmetric NCNM. The rectification ratio of the NCNM ionic diode can be modified flexibly by changing the working fluid and the geometry of the NCNM. It is found that with the presence of cationic surfactant in the working fluid, the rectification ratio increases more than 30 times from 3.03 to 109.77. Advanced functions of the developed ionic component, including working as an ionic transistor for current switching and integrating into an ionic diode bridge on a single nanofluidic chip for rectifying alternating current signals, are also demonstrated in this paper. The horizontally arranged NCNM ionic diode possesses the advantages of easy fabrication and integration that can be practically applied in the development of ionic electronics and biocomputing.