Nanogenerators (NGs) based on piezoelectric nanowires (NWs) have been developed as a key technology for converting ambient mechanical energy into electricity. In fact, researchers have shown that ZnO NWs can successfully convert external mechanical energy, biomechanical energy, thermal energy and magnetic energy into electricity. Developers have used NGs to build self-powered nanosystems such as ultraviolet (UV) sensors, wireless data transmission and Hg2+ ion sensors.

Direct measure of vibration

Now a team led by Zhong Lin Wang at the Beijing Institute of Nanoenergy and Nanosystems has shown that NGs can be used as an active sensor for detecting vibration. In the study, Wang and Aifang Yu, a postdoctoral fellow in the group, demonstrated a flexible, compact and lightweight NG as an active sensor for detecting the vibration spectrum of a drum membrane without the use of an external power source.

The output current/voltage signal of the NG provides a direct measure of the strain of the local vibrating drum membrane and contains rich detail, notably the vibration frequency, vibration speed and vibration amplitude.

In testing, data from the self-powered, low-cost vibration sensors was compared with laser vibrometer readings, which showed that the NG-based devices were capable of detecting the local vibration frequency of the drum membrane accurately.

A spatial arrangement of NGs on the membrane can deliver position-dependent vibration information of the surface. The measured frequency spectrum can be understood based on theoretically calculated vibration modes. This work further expands the application of NGs.

Full details can be found in the journal Nanotechnology.