Operando atomic force microscopy study of electric double-layer transistors based on ionic liquid/rubrene single crystal interfaces

We conducted the operando atomic force microscopy (AFM) of ionic liquid (IL)/rubrene single crystal interfaces under the operation of an electric double-layer (EDL)-gated field-effect transistor (FET). We developed a top-side-gated EDL-FET and performed the simultaneous measurement of device characteristics and frequency-modulation AFM in the IL droplet. The AFM images revealed microscopic and macroscopic changes in the rubrene single crystal surface upon carrier injection by applying a gate voltage.