Ultra-long W microfiber achieving 0.2 Ω sq−1 @ 90% transparency as new-type high-performance flexible transparent conductor

Abstract

The fast development of optoelectronics makes a huge boost to the searching for flexible indium-free transparent conductors. In recent years, metal networks (currently are Au, Ag and Cu) have emerged as promising alternatives, however, facile fabrication of high-performance, chemically stable, and low-cost transparent conductor is still a big challenge. Here, ultra-long W microfibers (with conductivity of 4.3 × 104 S/cm) are successfully produced by draw spinning and further assembled into well-regulated patterns. Such a solution-processed patterning effectively eliminates the fiber-to-fiber joint resistance, and thus enables the W network to achieve an ultra-low sheet resistance of 0.2 Ω sq−1 at ~90% transparency, which corresponds to a high figure of merit σdc/σopt = 1.7 × 104 (up to 10–40 times the value of Cu and Au networks). Moreover, the W network possesses excellent anti-thermal and anti-corrosion properties, which enable it to work in the erosion solution with pH ranging from 1 to 13 with a restrained increase (<3%) in its sheet resistance. With a marvelous combination of high conductivity and transparency, high chemical stability and good mechanical flexibility, the ultrathin W fibers may open a new door to find flexible indium-free transparent conductors for the development of both flexible electronics and energy conversion.