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Energy harvesting

Energy harvesting (also known as power harvesting or energy scavenging or ambient power) is the process by which energy is derived from external sources (e.g., solar powerthermal energywind energysalinity gradients, and kinetic energy, also known as ambient energy), captured, and stored for small, wireless autonomous devices, like those used in wearable electronics and wireless sensor networks[1].

The use of piezoelectric materials to harvest power has already become popular. Piezoelectric materials have the ability to transform mechanical strain energy into electrical charge. Piezo elements are being embedded in walkways[24][25][26] to recover the “people energy” of footsteps. They can also be embedded in shoes[27] to recover “walking energy”.

Researchers at FFM lab developed the first micro-scale piezoelectric energy harvester using thin film of PVDF nanofiber in 2005.[28] Sorayani and Bagherzadeh invented the Ultra Wide-Bandwidth micro-scale piezoelectric energy harvesting device by exploiting the nonlinear stiffness of a doubly clamped microelectromechanical systems (MEMSs) resonator.

In 2018, Soochow University researchers reported hybridizing a triboelectric nanogenerator and a silicon solar cell by sharing a mutual electrode. This device can collect solar energy or convert the mechanical energy of falling raindrops into electricity.[33]


Electrospun Fibrous Materials

Electrospinning is a fiber production method which uses electric force to draw charged threads of polymer solutions or polymer melts up to fiber diameters in the order of some hundred nanometers. Electrospinning shares characteristics of both electrospraying and conventional solution dry spinning of fibers.[1]

Electrospinning has the unique ability to produce nanofibers of different materials in various fibrous assemblies. The relatively high production rate and simplicity of the setup makes electrospinning highly attractive to both academia and industry. A variety of nanofibers can be made for applications in energy storage, healthcare, biotechnology, environmental engineering, and defense and security.

In our laboratory, nanofiber meshes are also being tested as harvesting energy. To be used as harvesting devices, electrospun nanofibers must be surface functionalized with nanosized piezoelectric material. In this regard, Dr Sorayani functionalized PVDF nanofibers with ZnO nanostructers. The result of this project published on ….