Adhesive Calcium Alginate Networks Enable Robust Silver Nanowire Electrodes for Flexible Electronics

Abstract

Silver nanowires (AgNWs) deposited on plastic substrates show potential as electrodes for flexible electronics but face challenges due to high surface roughness and poor compatibility with organic plastics. To overcome these issues, this study incorporates calcium alginate, a cross-linked polymer binder, into the electrodes through the cross-linking of sodium alginate with calcium chloride. This method offers several advantages. Firstly, calcium alginate fills the gaps between AgNWs, reducing surface roughness. Additionally, Cl− ions aid in the welding of AgNW junctions, enhancing conductivity. Furthermore, the carboxylate and hydroxyl groups in calcium alginate establish robust interactions with both AgNWs and plastic substrates, bolstering electrode durability. The resulting electrodes exhibit favorable characteristics, including a reduced roughness of 8.4 nm, a low sheet resistance of 8.3 Ω cm−2, high transmittance (91.2% at 550 nm), and exceptional resistance to air, solvents, and mechanical stress. Consequently, flexible organic solar cells with these electrodes display superior mechanical resilience, maintaining over 96% of their initial power conversion efficiency (PCE) even when subjected to a small fixed bending radius of 1 mm for 1,000 cycles. Furthermore, these devices even experience less than an 8% PCE decrease after 10,000 bending cycles at a radius of 2.5 mm.