Enhanced strain in functional nanoporous gold with a dual microscopic length scale structure

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Nanoporous gold (np-Au) is a versatile material with applications in catalysis and sensing.
• Traditional np-Au exhibits a single length scale of porosity.
• Enhancing the functional properties of np-Au requires novel structural designs.

Purpose of the Study:

• To synthesize nanoporous gold with a dual microscopic length scale.
• To investigate the relationship between precursor alloy grain size and the resulting material structure.
• To evaluate the impact of the dual length scale structure on charge-induced strain properties.

Main Methods:

• Synthesis of nanoporous gold by exploiting the crystal structure of an alloy precursor.
• Characterization of the mesoscopic material, focusing on stacked gold layers and nanoporosity.
• Tailoring layer thickness via control of the alloy precursor's grain size.
• Measurement of charge-induced strains.

Main Results:

• Successful synthesis of nanoporous gold with stacked layers of submicrometer thickness, each exhibiting bulk nanoporosity.
• Demonstrated tunability of layer thickness by controlling the grain size of the alloy precursor.
• Achieved charge-induced strains up to 6%, approximately two orders of magnitude greater than standard nanoporous gold.
• Presented a model to explain the observed phenomena.

Conclusions:

• The dual length scale structure in nanoporous gold significantly enhances its functional properties.
• Tailoring the mesoscopic structure offers a pathway to superior performance in nanoporous materials.
• The findings open new avenues for designing advanced nanoporous gold-based devices.