Copper micromesh-based lightweight transparent conductor with short response time for wearable heaters

• Published in: Micro and nano systems letters Vol. 9; no. 1; pp. 1 - 10
• Main Authors: Kim, Han-Jung, Kim, Yoonkap
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 25.10.2021; Springer Nature B.V; SpringerOpen
• Subjects: Actuators; Applied and Technical Physics; Circuits and Systems; Conductors; Copper; Electrical Engineering; Electrical properties; Engineering; Heat transmission; Indium tin oxides; Letter; Light transmittance; Lightweight; Mechanical Engineering; Metal mesh; Nanotechnology; Ohmic dissipation; Optical properties; Oxide coatings; Polyvinyl alcohol; Resistance heating; Response time; Substrates; Thermal response; Thermal response time; Thickness; Transfer printing; Transparent conductor; Wearable technology; Wearable transparent heater; Thermal response time; Wearable transparent heater; Metal mesh; Transparent conductor; Transfer printing
• ISSN: 2213-9621; 2213-9621
• DOI: 10.1186/s40486-021-00132-5

Thickness-controlled transparent conducting films (TCFs) were fabricated by transfer printing a 100 nm thick Cu micromesh structure onto poly(vinyl alcohol) (PVA) substrates of different thicknesses (~ 50, ~ 80, and ~ 120 μm) to develop a lightweight transparent wearable heater with short response time. The Cu mesh-based TCF fabricated on a ~ 50 µm thick PVA substrate exhibited excellent optical and electrical properties with a light transmittance of 86.7% at 550 nm, sheet resistance of ~ 10.8 Ω/sq, and figure-of-merit of approximately 236, which are comparable to commercial indium tin oxide film-based transparent conductors. The remarkable flexibility of the Cu mesh-based TCF was demonstrated through cyclic mechanical bending tests. In addition, the Cu mesh-based TCF with ~ 50 μm thick PVA substrate demonstrated a fast Joule heating performance with a thermal response time of ~ 18.0 s and a ramping rate of ~ 3.0 ℃/s under a driving voltage of 2.5 V. Lastly, the reliable response and recovery characteristics of the Cu mesh/PVA film-based transparent heater were confirmed through the cyclic power test. We believe that the results of this study is useful in the development of flexible transparent heaters, including lightweight deicing/defogging films, wearable sensors/actuators, and medical thermotherapy pads.