Joint-Free Single-Piece Flexible Thermoelectric Devices with Ultrahigh Resolution p–n Patterns toward Energy Harvesting and Solid-State Cooling

Joints widely exist in traditional organic electronic devices that are composed of p–n modules, including organic thermoelectric (TE) devices. They often harm the performance of the devices by increasing their electrical resistance and thermal resistance. Recently, a few joint-free approaches have been reported to fabricate TE devices with a single carbon nanotube (CNT) composite film. However, the resolution of p–n patterns is low, e.g., >100 μm, with a conventional printing/drop-casting method. Herein, a plasma treatment method was reported to fabricate joint-free TE devices with a single-piece flexible CNT composite film whose performance was higher than that of traditional devices in energy harvesting and solid-state cooling. In addition, this method provided p–n patterns with a high resolution of ∼1–2 μm which is promising for making future high integration level TE devices. This method can be extended to fabricate a broad range of high integration level organic electronic devices composed of p–n modules.