Wavelength-influenced electrical performance of laser-written flexible copper-based structures

Area of Science:

• Materials Science
• Nanotechnology
• Laser Processing

Background:

• One-step direct laser writing is effective for flexible metal structures.
• Laser wavelength's impact on flexible copper structuring is not well understood, limiting manufacturing.
• Developing universal laser writing processes requires understanding wavelength effects.

Purpose of the Study:

• To investigate the feasibility of one-step laser writing of flexible copper (Cu) structures using different continuous diode laser wavelengths.
• To clarify the influence of laser wavelength on the photothermal reaction and subsequent Cu structure formation.
• To optimize laser parameters for enhanced flexible Cu structure properties.

Main Methods:

• Utilized one-step direct laser writing with continuous diode lasers of varying wavelengths (532 nm and 808 nm).
• Analyzed the photothermal reaction mechanism driving the decomposition of reducing agents to form Cu.
• Characterized the resulting Cu structures, focusing on reduced-joining degree, conductivity, adhesion, and bendability.

Main Results:

• Confirmed the feasibility of one-step laser writing for flexible Cu structures with different wavelengths.
• Demonstrated that laser wavelength significantly affects photothermal reaction amplitude, influencing Cu structure formation.
• The 532 nm laser induced a stronger photothermal reaction than the 808 nm laser.
• Cu structures fabricated with 532 nm laser exhibited higher reduced-joining degree, superior conductivity, adhesion, and bendability.

Conclusions:

• Laser wavelength is a critical parameter in direct laser writing of flexible Cu structures.
• The 532 nm laser offers advantages over the 808 nm laser for fabricating high-performance flexible Cu structures.
• Successfully fabricated functional strain sensors using 532 nm laser-written Cu structures, showcasing practical applicability.