Ultrathin Sticker-Type ZnO Thin Film Transistors Formed by Transfer Printing via Topological Confinement of Water-Soluble Sacrificial Polymer in Dimple Structure

To create ultrathin sticker‐type electronic devices that can be attached to unconventional substrates, it is highly desirable to develop printable membrane‐type electronics on a handling substrate and then transfer the printing to a target surface. A facile method is presented for high‐efficiency transfer printing by controlling the interfacial adhesion between a handling substrate and an ultrathin substrate in a systematic manner under mild conditions. A water‐soluble sacrificial polymer layer is employed on a dimpled handling substrate, which enables the topological confinement of the polymer residue inside and near the dimples during the etching and drying processes to reduce the interfacial adhesion gently, creating a high yield of transfer printing in a deterministic manner. As an example of an electronic device that was created using this method, a highly flexible sticker‐type ZnO thin film transistor was successfully developed with a thickness of 13 μm including a printable ultrathin substrate, which can be attached to various substrates, such as paper, plastic, and stickers. Topologically confining a water‐soluble sacrificial polymer layer on a dimpled handling substrate enables controllability of the interfacial adhesion force between the ultrathin substrate and a handling substrate. This technology provides a high yield of transfer printing in a deterministic manner without altering the position of printable designs to formulate sticker‐type ZnO thin film transistors.