Silver nanowires (AgNWs) have been investigated as alternatives to indium tin oxide in transparent conductive films (TCFs) for electronics. However, AgNW TCFs still pose stability issues when exposed to thermal, chemical, and mechanical stimuli. Herein, we demonstrate a facile and effective route to improve stability by treating the films with dilute ferric chloride solution. Our results indicate that after treatment the films exhibit a dramatically enhanced stability against aging, high temperature oxidation, chemical etching, sulfurization, and mechanical straining. Size-dependent instability is fully explored and explained regarding surface atomic diffusion, which could be blocked by enhancing the activation energy of surface diffusion through forming a AgCl cap under ferric chloride solution treatment. Chemisorption-related Fermi level shift of silver nanowires is applied to tune their chemical reactivity to ferric chloride solution for balancing between size-dependent stability improvement and maintaining optoelectrical properties. Owing to the dilute treatment solution, the treated films exhibit a negligible change in light transmittance, whereas sheet resistance decreases by 30% and flexibility increases because of capillary-force-induced welding of contacting AgNWs and AgCl layer mediated tightening. These findings are significant for real-world applications of AgNW TCFs.
A sandwich-structured bottom hard-coat/silver nanowire/top hard-coat (BHC/AgNW/THC) transparent conductive film (TCF) has been prepared by embedding the functional AgNW layer between two HC layers. The BHC/AgNW/THC TCFs show high scratch resistance with a hardness of 3H due to the enhanced adhesion to the substrate. In addition, the BHC/AgNW/THC TCFs exhibit a transmittance of 90.6% and a haze of 1% at 550 nm under a sheet resistance of 72 Ω/sq. Furthermore, highly enhanced long-term stability has been guaranteed by the HC layers due to their excellent gas barrier property. The amazing fact is that hard coating has little effect on the flexibility of AgNW films especially under extreme bending conditions and negligible resistance change could be observed after bending over thousands of times. Consequently, the greatly improved performance of BHC/AgNW/THC TCFs provided by employing hard coating layers paves the way for real-world applications of flexible AgNWs in vast areas that rigid indium tin oxide is not suitable.
Silver nanowire films have a wide application prospect in flexible electronics, while it is a noticeable problem that the silver nanowires break due to the shear force under the mass production film cutting or extreme service conditions. In this paper, the shear fracture behaviour of silver nanowire films with different structural parameters was studied under the extreme shear failure tests. The load–displacement curve was obtained from the nano-indentation test, while the hardness H , the elastic modulus E and the plastic properties represented by the ratio of H3 / E2 of silver nanowire films with different diameters and thicknesses were calculated. On the other hand, based on the load–displacement curve, the stress–strain curve can be obtained through the finite element method simulation. The plastic properties can also be judged by the lower limit of yield strength from simulated stress–strain curve. Combined with characteristic crack propagation range, the relationship between plasticity and shear fracture was found, which was further disclosed by in-depth microstructure analysis. The results show that the better the plasticity of silver nanowire films, the stronger the resistance to shear fracture.
Silver nanowires synthesized by the most commonly used polyol method are typically accompanied by nanoparticles and nanorods, which have a negative impact on the performance of silver nanowire-based devices. Herein, we report a reproducible and easy method for preparing silver nanowires with yields exceeding 70% by optimizing the heterogeneous nucleation of silver from silver chloride precursors and regulating the reduction in ethylene glycol. The yield of silver nanowires depended on the morphology and concentration of silver chloride and the decomposition time of ethylene glycol. The Raman spectra were used to study the effect of the decomposition time of ethylene glycol on the concentration of acetaldehyde in solution, which influenced the reduction rate of silver ions. Then, the reaction time of silver nanowires was further reduced from 24 min to 10 min by increasing the reaction temperature from 160 °C to 170 °C. On the basis, the silver nanowire based capacitive screen with a good capacitive response and anti-aging performance was further fabricated. This method provides a new way for the macro preparation of silver nanowires with high yields.