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.