Self-assembly based plasmonic arrays tuned by atomic layer deposition for extreme visible light absorption

Area of Science:

• Nanotechnology
• Metamaterials
• Plasmonics
• Optical Engineering

Background:

• Efficient light absorption is crucial for solar energy conversion, demanding minimal material usage for economic and efficiency gains.
• Exploring ultimate light absorption limits per unit volume is a key challenge in metamaterial science and nanosynthesis.

Purpose of the Study:

• To investigate the potential of metamaterials and nanosynthesis for achieving ultimate light absorption limits.
• To engineer ultrathin plasmonic nanostructures for enhanced light harvesting.

Main Methods:

• Utilized block copolymer lithography and atomic layer deposition to precisely control optical properties at the atomic scale.
• Employed critical coupling, guided by an analytical model and spectroscopic ellipsometry, to maximize light absorption.

Main Results:

• Achieved over 99% light absorption in a nanocomposite layer.
• Demonstrated that 93% of absorption occurred within an effective gold thickness of only 1.6 nm.
• Reported a record effective absorption coefficient of 1.7 × 10^7 cm⁻¹ in the visible spectrum, surpassing existing materials.

Conclusions:

• The developed nanoengineered system significantly pushes the boundaries of light harvesting in ultrathin materials.
• This approach offers a new pathway for highly efficient, low-volume light absorption systems for various applications.