Bioinspired Ionic Diodes: From Unipolar to Bipolar

Bioinspired ionic diodes, as the building blocks for bioinspired ion channels, are extensively explored to mimic the ion transport functions of biological ion channels. Bioinspired nanochannels and nanopores are much more stable and robust than their biological counterparts and can be practically applied in many fields. This review summarizes the recent development of ionic diodes in both experimental and theoretical studies. First, the two types of ionic diodes, unipolar and bipolar, are introduced to give an overview of the nanofluidic field. Then, each type of ionic diode is described in detail and focuses on bipolar ionic diodes for their excellent control of ion transport. Furthermore, the applications of ionic diodes in sensing and energy conversion fields are summarized. In the last section, a perspective on the future development of ionic diodes is provided.