Wang and Song firstly reported the piezoelectric “nanogenerators”
in 2006, which can generate impulsive output voltage
with several millivolts by bending a ZnO nanowire with the
atomic force microscopy (AFM)’s tip [6]. This nanogenerator
has attracted great interest of researchers due to the
great potential in the application of micro/nanoscaled power
supply systems. However, the energy conversion efficiency
and output power of this early-stage device are too low to
be applied. In the last 8 years, researchers have done great
efforts on improving the device performance, including the
employing of several kinds of piezoelectric materials with
higher piezoelectric properties [7–9], the design of device
structures [10, 11], and the hybrid of nanogenerators with
other types of energy harvesters [12, 13]. Moreover, some
novel applications such as the active chemical sensors were
also developed by using the nanogenerators [14, 15].As shown
in Figure 1, the publication and citation number of research
works have largely increased from the first report in 2006.
In this paper, we firstly reviewed the fundamental theory
about the piezoelectricity and piezoelectric materials
in Section 2. Then the working mechanism, modeling and
structural design, and the fabrication and performance of the
piezoelectric nanogenerators based on different structures
were discussed. After that, the application of piezoelectric
nanogenerators in recent years was briefly reviewed. Finally,
the future development of the nanogenerators was also
discussed.