Passivation coating on electrospun copper nanofibers for stable transparent electrodes

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Copper nanofibers are promising transparent electrode materials due to low cost and good conductivity.
• Their application is limited by poor durability against oxidation and corrosion, leading to increased sheet resistance.
• Indium tin oxide (ITO) is the current standard but is brittle and expensive.

Purpose of the Study:

• To enhance the durability of copper nanofibers for transparent electrode applications.
• To investigate the effectiveness of atomic layer deposition (ALD) for protective coatings.
• To evaluate the performance of aluminum-doped zinc oxide (AZO) and aluminum oxide coatings on copper nanofibers.

Main Methods:

• Electrospinning of copper nanofibers.
• Atomic Layer Deposition (ALD) of aluminum-doped zinc oxide (AZO) and aluminum oxide passivation layers.
• Thermal oxidation and chemical corrosion testing.
• Sheet resistance measurements before and after treatments.
• Analysis of PEDOT:PSS layer interaction.

Main Results:

• AZO-coated copper nanofibers exhibited only a 10% increase in sheet resistance after thermal oxidation (160 °C dry air, 80 °C humid air).
• Bare copper nanofibers became insulating under similar conditions.
• AZO-coated copper nanofibers showed an 18% increase in sheet resistance after PEDOT:PSS coating, compared to a 6-order increase for bare nanofibers.

Conclusions:

• ALD-deposited AZO and aluminum oxide coatings effectively enhance the durability of copper nanofibers.
• Protected copper nanofibers maintain low sheet resistance under harsh conditions, making them suitable for transparent electrodes.
• This passivation strategy overcomes a key limitation of copper-based transparent conductive films.