In the preceding chapters, various hierarchical nanostructures for energy efficient electronics applications among energy devices have been discussed. Electronics are the final stage for energy cycles and basically consume energy that was generated by energy harvesting devices and energy storage devices. Among the biggest electronics using nanostructures are displays (Chapter 10) and sensors (Chapter 11). Additionally, the application of hierarchical nanostructures can be found in various research topics: (1) highly efficient energy consumption devices including transparent conductors, highly flexible and stretchable electrodes, light emitting diodes, and (2) mechanical hierarchical nanostructures, for example, for super-hydrophobic and self-cleaning surfaces, pool boiling enhancement for more efficient heat transfer, and gecko-inspired adhesives. As long as the surface area or surface characteristics are considered an important factor to enhance the functionality of the devices, applying hierarchical nanostructures is one of the most powerful and promising approaches with a very high degree of design freedom.