Fabrication of 3D-Ordered Nanoporous Gold for Chemical Sensors

3D ordered nanoporous materials provide high surface-to-volume ratio and controlled nano-scale periodic architecture, making them attractive for applications such as energy storage, catalysis, separations, chemical sensing, and tissue engineering. 3D-ordered nanoporous gold structures were fabricated by electrodeposition of gold into colloidal crystal templates formed by self-assembly. The structures are replicas of the colloidal crystal and have pore sizes and feature sizes that are dependent on the particle size. When the dimensions of a conductor are sufficiently small the resistance is dominated by surface scattering. A prototype chemical sensor was created exploiting this architecture. Molecules with sulfhydryl groups adsorb strongly to gold surfaces and can be monitored by the change in resistance. A resistance change of approximately 2 percent was achieved and a chemical sensor based on surface scattering has been demonstrated.