A leaf vein-like hierarchical silver grids transparent electrode towards high-performance flexible electrochromic...

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Flexible transparent conducting electrodes (TCEs) are vital for wearable optoelectronic devices.
• Existing TCEs often face challenges in balancing optical transmittance and electrical conductivity.

Purpose of the Study:

• To fabricate a large-area flexible TCE using a novel leaf vein-like hierarchical metal grid (HMG) structure.
• To evaluate the performance of the HMG-based TCE in terms of optical and electrical properties.
• To demonstrate the application of the HMG TCE in flexible electrochromic devices (ECDs).

Main Methods:

• Fabrication of large-area flexible TCEs using hierarchical metal grids (HMGs) with mesoscale 'trunk' and microscale 'branches'.
• Utilized laser-etching for trunk grids and self-formed branched grids for uniform electron transport.
• Optimized TCE performance by adjusting grid dimensions and TiO2 colloidal crackle patterns.

Main Results:

• Achieved high optical transmittance (~81%) and low sheet resistance (1.36 Ω sq⁻¹) with Ag HMGs.
• Demonstrated uniform conducting paths due to the hierarchical grid structure.
• Successfully fabricated flexible electrochromic devices (ECDs) with remarkable cyclic performance using the HMG TCE.

Conclusions:

• The developed HMG-based TCE offers excellent transparency, conductivity, and flexibility.
• This HMG structure presents a promising solution for next-generation flexible and wearable optoelectronic applications.
• The design allows for simple optimization of performance characteristics.