Triple energy harvester

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Until now, most energy collectors “tapped” a single source to get small quantities of energy. But not enough for an entire host of applications. Now a special material that transforms light, heat and mechanical deformation into electricity is supposed to do it better.

Energy harvesting is an old hand when it comes to media presence. However, actual applications are much more difficult to find than headlines on the topic. But at the beginning of the year, a team from the Microelectronics Research Unit at the University of Oulo in Finland that wanted to harvest energy from three of the most common sources of renewable energy made the world sit up and take notice. The key is supposedly a new type of ferroelectric material that is based on a crystalline perovskite structure with the catchy name KBNNO.

Perovskites are important materials for electronic and electromechanical components. Their spontaneous and switchable polarization are predominantly used to manufacture nonvolatile memories. And the piezoelectric properties associated with ferroelectricity result in ultra-precision mechanical actuators such as those used in atomic force microscopes or for positioning in fuel injection devices.

Conversely, ferroelectric materials transform heat as well as mechanical deformation into usable electric energy. In addition, due to their photoelectric properties, perovskites are already being used in solar cells with efficiency rates of more than 20 percent. In other words, it is a material with multiple “talents”.

The triple energy harvester concept works

Still, until now it has only been possible to use one of its effects as an energy source at a time. Now researchers in “Advanced Materials” have proof that their idea of a triple energy harvester from the beginning of the year can be implemented in actual practice.

Manufacturing perovskite crystals is relatively simple, so the technology should be marketable within a few years. However, it will be necessary to optimize the material with regard to its chemical composition. Right now is still contains sodium, which lowers the band gap.

However, if energy harvesters that use KBNNO are supposed to really be marketed on a large scale, gigantic applications await the miracle material: from supplementing rechargeable batteries to replacing them in all kinds of compact devices and in billions of sensors on the Internet of Things and in smart cities.


Energy Harvester  (Image: University of Oulu).

A new “miracle material” responds to pressure, light and heat with electricity. (Photo: University of Oulu). (Image: University of Oulu).