Interfacial functionalization and capillary force welding of enhanced silver nanowire-cellulose nanofiber composite electrodes for electroluminescent devices

The development of flexible, intelligent, and lightweight optoelectronic devices based on flexible transparent conductive electrodes (FTCEs) utilizing silver nanowires (AgNWs) has garnered increasing attention. However, achieving low surface resistance, strong adhesion to the flexible substrate, low surface roughness, and green degradability remains a challenge. Here, a composite electrode combining natural polymer cellulose nanofibers (TCNFs) with AgNWs was prepared. This process includes non-covalent interface embedding between TCNFs and AgNWs as well as a strong capillary force between the hydrophilic TCNF substrate and AgNWs during water mist capillary force cold welding. By adding ethanolamine and employing a rapid water mist wetting-drying process (within 10 s), the performance of TCNF/AgNW FTCEs significantly improves with reduced sheet resistance (8.3 Ω sq.^-1), high light transmission (84.9 %), and low surface roughness (9.9 nm). Additionally, the composite electrode exhibits excellent stability and durability under various conditions such as bending, adhesion, and tensile stress. The prepared flexible electroluminescent device achieves high luminous intensity (43.6 cd m^-2) and excellent operational stability, thanks to the outstanding performance of the composite electrode. This study presents a simple strategy for fabricating FTCEs using nanocellulose combined with AgNWs offering a potential material option for key components in green flexible optoelectronic devices.