Two types of thin-film electrochemical devices (electrolyte-gated transistors and electrochemical light-emitting cells) are demonstrated using area-controllable ionogel patches generated by transfer-stamping. For the successful transfer of ionogel patches on various target substrates, thermoreversible gelation by phase-separated polymer crystals within the ionogel is essential because it allows the gel to form a conformal contact with the acceptor substrate, thereby lowering the overall Gibbs energy of the system upon transfer of the ionogel. This crystallization-mediated stamping provides a much more efficient deposition route for producing thin films of ionically conductive high-capacitance solid ionogel electrolytes. The lateral dimensions of the transferred ionogels range from 1 mm × 1 mm to 40 mm × 40 mm. These ionogel patches are incorporated in organic p-type and inorganic n-type thin-film transistors and electrochemical light-emitting devices. The resulting transistors show sub-1 V device operation with high transconductance currents, and the optoelectronic devices emit orange light through a series of electrochemical redox reactions. These results demonstrate a simple yet versatile route to employ physical ionogels for various solid-state electrochemical device applications.
Keywords: electrochemical light-emitting device; electrolyte-gated transistor; ionogel; physical gel; transfer-stamping.