Organic Thin-Film Transistors on Ultrathin Elastomeric Substrates for Conformable, Stretchable, and Breathable...

Flexible electronics have utilized unconventional substrates, such as ultrathin plastics, elastomers, and nanomeshes, rapidly expanding their application. Conformability, stretchability, and breathability are crucial properties to enable attachment onto biological surfaces, such as skin, which are complex-shaped, deformable, and evaporative. Ultrathin elastomeric substrates provide all three of them, while offering a continuous platform. However, fabrication of active components on ultrathin elastomeric substrates remains challenging due to their fragility and processing incompatibility. Here, we report organic thin-film transistors (OTFTs) on ultrathin elastomeric substrates. The OTFTs were placed on 0.3 μm-thick plastic islands on a 2.0 μm-thick nanofiber-reinforced elastomer substrate, resulting in a total thickness of ∼2.5 μm. The direct fabrication of plastic islands and OTFTs were enabled by adhesion control of the substrates, support film, and mask film. The resulting OTFTs maintained stable electrical performance under 100% stretching, 10,000 stretching to 50% strain, and wrinkling (bending radii of 3-100 μm), while preserving gas-permeability and ultraconformability. A pseudocomplementary-metal-oxide-semiconductor (pseudo-CMOS) inverter circuit fabricated on the substrate demonstrated a gain of 37 at 10 V, confirming the circuit-level feasibility. We expect our method will enable advanced multifunctional electronics with conformability, stretchability, and breathability required for on-skin devices.