High performance and low cost transparent electrodes based on ultrathin Cu layer

Area of Science:

• Materials Science
• Optoelectronics
• Thin Film Technology

Background:

• Transparent electrodes are crucial for optoelectronic devices.
• Ultrathin metal layers offer potential but face challenges in performance and stability.
• Copper (Cu) is a cost-effective alternative to indium tin oxide (ITO).

Purpose of the Study:

• To optimize transparent electrodes using an ultrathin copper layer sandwiched between dielectric layers.
• To enhance both optical transmittance and electrical conductivity.
• To investigate the impact of sputtering parameters on electrode performance.

Main Methods:

• Transfer matrix simulations were employed to screen various dielectric materials for maximizing broad-band transmittance.
• Sputtered electrodes were fabricated with copper (Cu) embedded between titanium oxide (TiO_X) coated substrates and aluminum-doped zinc oxide (AZO) top layers.
• The effect of sputtering power on copper island coalescence and subsequent electrode properties was investigated.

Main Results:

• The optimized electrode design demonstrated superior optical and electrical performance compared to previous copper-based electrodes.
• Increased sputtering power led to improved island coalescence in ultrathin copper layers, enhancing performance.
• Simulations indicated that the optimal electrode design for air ambient requires adaptation for integration into inverted perovskite solar cells.

Conclusions:

• Ultrathin copper electrodes embedded between dielectrics can be effectively optimized for high performance.
• Sputtering process parameters significantly influence the microstructure and properties of copper electrodes.
• Integration into specific device architectures, like perovskite solar cells, necessitates tailored electrode designs.