Electrolyte gating using ionic crystals: Demonstration of iontronics with ionic crystals

We perform electrolyte gating using ionic crystals instead of conventional ionic liquids and gels. By applying a gate voltage and heating the ionic crystal to a liquid state, Fermi level tuning of a carbon nanotube (CNT) film was achieved. Subsequent resolidification at room temperature ensured a fixed ion distribution in the electric double layer at the tuned state. The CNT film maintained the tuned Fermi level for over 30 days, even after the gate electrode was removed. This addresses the challenges associated with handling conventional ionic liquids and is poised to revolutionise the field of electrolyte gating for nanomaterial devices.