Morphology-controlled silver nanowire synthesis using a cocamidopropyl betaine-based polyol process for flexible and stretchable electronics

Silver nanowire (AgNW) based transparent conductive films (TCFs) are promising building blocks for flexible and stretchable electronics to replace brittle metal oxides. Ultra-long AgNWs are preferred for enabling TCFs with excellent photoelectric properties and mechanical flexibility. Herein, a novel polyol process is proposed for the synthesis of ultra-long AgNWs, with the new finding that the addition cocamidopropyl betaine (CAB) to polyol synthesis allows the rapid production of AgNWs with an average length of ∼120 μm in a high yield of ∼90%. Also, a cocamidopropyl betaine assisted polyol method for the synthesis of ultra-long AgNWs is demonstrated with a possible mechanistic explanation. The prepared AgNWs are coated on a polyethylene glycol terephthalate (PET) substrate to fabricate a flexible transparent conductive film, which exhibits a low sheet resistance of ∼200 Ω sq(−1) at 88.74% transmittance with a negligible change of sheet resistance after bending. In addition, flexible TCFs based on the resulting AgNWs reveal excellent mechanical flexibility and high cyclic stability after 300 cycles of bending. The new polyol process in this work will provide a greater possibility for the practical application of long AgNWs towards flexible and wearable optoelectronic devices.