Transparent AgNW-CoNPs conducting film for heat sensor

We have fabricated transparent conducting film (TCF) from silver nanowires (AgNWs) decorated with cobalt nanoparticles (CoNPs) on a thermoplastic polyimide (PI) substrate by solution processed spin-coating approach. AgNWs and CoNPs were produced by modified polyol methods using poly(N-vinylpyrrolidone) PVP (Mw ≈ 1,300,000). The concentration ratio of AgNWs to CoNPs was varied as 1:0, 0.7:0.3, 0.5:0.5, and 0.3:0.7 (in wt%). The results show that increasing the AgNWs/CoNPs concentration up to 0.5: 0.5 raises the TCF temperature interestingly to 350 °C before the Joule heating breakdown occurs at 20 V. However, at a higher content of CoNPs (AgNWs: CoNPs = 0.3:0.7), due to the excessive entanglement of CoNPs in the AgNW network, the temperature further drops down to 65 °C. The optimum transmittance (94%), sheet resistance (52 Ω/□), and thermal stability were obtained at a concentration ratio of AgNWs: CoNPs = 0.5:0.5. The stabilization mechanism is also suggested for the extremely high temperature obtained in this work.