Developing novel technologies for wireless nanodevices and nanosystems are of critical importance for in-situ, real-time and implantable biosensing, biomedical monitoring, and biodetection. Nanosensors are currently under intense development for ultrasensitive and real-time detection of biomolecules. An implanted wireless biosensor, for example, requires a power source, which may be provided directly or indirectly by the charging of a battery. It is highly desired for wireless devices and even required for implanted biomedical devices to be self-powered without using a battery.

“This work demonstrates the first work for achieving nano-scale energy conversion by nanowire nanotechnology. This is also the first example which shows that the coupling of piezoelectric and semiconducting properties is the key for the piezoelectric discharge process.”

The principle and technology demonstrated in the paper¹ have the potential of converting mechanical movement energy (such as body movement, muscle stretching, blood pressure), vibration energy (such as acoustic/ultrasonic waves), and hydraulic energy (such as the flow of body fluid, blood flow, contraction of blood vessels) into electric energy that may be sufficient for self-powering nanodevices and nanosystems.

The nano-generator could be the foundation for exploring new self-powering technology for in-situ, real-time and implantable biosensing, biomedical monitoring, and biodetection, with great potential for defense and civil applications. The technology can also be applied for building wireless, self-powered sensors by harvesting energy from the environment. The technology can also be used to generate electricity by body movement.

We have recently demonstrated that ZnO nanowires grown on conductive polymer can be effectively used for generating electricity².

This work demonstrates a new direction in nanotechnology research, termed as "nano-piezotronics"³, which utilizes the coupled piezoelectric and semiconducting properties of nanowires and nanobelts for designing and fabricating electronic devices and components, such as field effect transistors⁴ and diodes⁵. It is anticipated to have a wide range of applications in electromechanical coupled electronics, sensing, harvesting/recycling energy from the environment, and self-powered nanosystems.

This work demonstrates the first work for achieving nano-scale energy conversion by nanowire nanotechnology. This is also the first example which shows that the coupling of piezoelectric and semiconducting properties is the key for the piezoelectric discharge process. It lays down the foundation of using ZnO nanowires for fabricating electromechanical coupled devices and systems.

So far, innovations for delivering a nanoscale power source are almost non-existent; while huge emergent needs for nanoscale sensing devices continue for biological sensing and defense applications. Therefore, it is essential to explore innovative nanotechnologies for converting mechanical energy, vibration energy, and hydraulic energy into electric energy that will be used to power nanodevices without using a battery.

It also has a huge impact on miniaturizing the size of the integrated nanosystems by reducing the size of the power generator while improving its efficiency and power density. Once this is truly feasible, we have made the nanosystems. This was the motivation with which we started this research.

The objective of the follow up work is to develop a unique technology capable of converting mechanical movement energy, vibration energy, and hydraulic energy into electric energy that is sufficient for self-powering nanodevices and nanosystems in biological systems; and to fabricate large-power output electric generators using nanomaterials, which can be grown on substrates such as metal foils, flexible organic plastic substrates, ceramic substrates, and compound semiconductors, aiming at achieving flexible power sources for biomedical, defense and civil applications.