Surface Passivation of Cu Nanofiber Films Fabricated by Electrospinning for Transparent Conductive Films

Indium-tin oxide (ITO) transparent conductive films (TCFs) are widely used in electronic displays and solar cells. However, the brittleness and high cost of ITO are critical shortcomings for its applications in the next-generation flexible and low-cost electronics. As a novel substitution of ITO films, copper nanofiber films (CNFs) take the great advantages of low cost, high conductivity and excellent flexibility. Unfortunately, CNFs are sensitive to oxygen, which may cause severe performance deterioration over time. Here, we use an electrospinning (ES) approach to fabricate continuous CuAc
2
/PVP nanofibers, followed by their oxidation and reduction to obtain the CNFs. The as-prepared CNFs show transparency of 80.48 % and conductivity of ~60 ohm/sq. Subsequently, a simple solvothermal treatment with sodium formate endows the CNFs with superior anti-oxidation properties. With the assistance of in-situ transmission electron microscopy, the thermal response of the CuAc
2
/PVP nanofibers and the formation mechanism of Cu nanofibers were investigated. This study may contribute to the application of CNFs in the field of flexible optoelectronics and new display technology.