Abstract
Silver nanowire (AgNW) conductive film fabricated by solution processing was investigated as an alternative to indium tin oxide (ITO) in flexible transparent electrodes. In this paper, we studied a facile and effective method by electrodepositing Al2O3 on the surface of AgNWs. As a result, flexible transparent electrodes with improved stability could be obtained by electrodepositing Al2O3. It was found that, as the annealing temperature rises, the Al2O3 coating layer can be transformed from Al2O3·H2O into a denser amorphous state at 150 °C. By studying the increase of electrodeposition temperature, it was observed that the transmittance of the AgNW–Al2O3 composite films first rose to the maximum at 70 °C and then decreased. With the increase of the electrodeposition time, the figure of merit (FoM) of the composite films increased and reached the maximum when the time was 40 s. Through optimizing the experimental parameters, a high-stability AgNW flexible transparent electrode using polyimide (PI) as a substrate was prepared without sacrificing optical and electrical performance by electrodepositing at −1.1 V and 70 °C for 40 s with 0.1 mol/L Al(NO3)3 as the electrolyte, which can withstand a high temperature of 250 °C or 250,000 bending cycles with a bending radius of 4 mm.
Highlights
AgNWs dispersion in ethanol was spin-coated on a substrate annealed at 110 ◦ C for 30 min to fabricate transparent electrodes for electrodeposition
To analyze the influence of Al2 O3 coating on the optical properties of AgNWs at different deposition temperatures, the electrodeposition time was fixed at 40 s and 5 min and the samples were reacted at 40 ◦ C, 50 ◦ C, 60 ◦ C, 70 ◦ C, and 80 ◦ C, respectively
At 40 ◦ C, AgNWs were wrapped by an electrodeposited layer with a thickness equivalent to one wire diameter after only 40 s, and they were completely covered by the entire film when it was deposited for 5 min
Summary
With the development of flexible devices, indium tin oxide (ITO) cannot always be used as flexible transparent electrode due to its fragility and its high preparation temperature that may damage flexible substrates. New types of transparent conductive films suitable for flexible substrates such as silver nanowires (AgNWs) [1], carbon nanotubes [2], graphene [3], and metal grids [4] have begun to emerge. The AgNW conductive film fabricated by solution processing can achieve better optical and electrical performance than ITO, but can be compatible with the low-temperature preparation process required for flexible display [5,6,7]. AgNWs still have to solve several problems such as reliability, which are mainly manifested in the following aspects. AgNWs still have to solve several problems such as reliability, which are mainly manifested in the following aspects. (1)
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