An ultra-stable and high-performing flexible transparent heater using tungsten oxide-covered silver nanowire films embedded in polymer

Abstract

The remarkable conductivity and flexibility of a transparent heater (TH) fabricated using silver nanowires (AgNWs) make it a promising material for flexible electronic applications. However, issues such as oxidation, poor adhesion, and low thermal stability hinder practical applications. In this work, we fabricate a long-lasting and high-performing conductive, transparent and flexible electrode by coating AgNWs with tungsten oxide (WO_x) and embedding within a polyimide (PI) matrix. The uniform WO_x thin layer coating increases the conductivity of the overall films by reducing the contact resistance and at the same time inhibits the surface oxidation of AgNWs by forming a core–shell structure. PI helps in enhancing their mechanical durability and increase in thermal stability. The transparent electrode obtained by coating AgNWs with tungsten oxide (WO_x) and embedding within a polyimide (PI) matrix with the structure of AgNWs–WO_x/PI delivered a sheet resistance of 5.3 ± 0.26 Ω □⁻¹ with 80% transparency and remains stable after a number of bending, peeling, and washing cycles. The TH fabricated from the AgNWs–WO_x/PI electrode of size 2.5 cm × 3 cm generated an extremely high temperature of 197 °C within 10 s by supplying a power of only 5 V, which remained stable after several repeated cycling tests.