The ability to convert excess heat into electricity for electronic devices has been a popular idea among engineers, material scientists, university research teams lately. Dr. Yi Gu and his team at Washington State University has developed a device called a van der Waals Schottky diode, which he hopes can make the dream of converting excess heat from electronics and automobile into usable electricity a reality.
Dr. Gu's research group in WSU's Department of Physics and Astronomy. Image courtesy of Washington State University.
The van der Waals Schottky Diode
What is the difference between a van der Waals Schottky diode and a regular ol' Schottky diode? Like a regular Schottky diode, the van der Waals diode directs electricity in a certain direction. What separates the van der Waals Schottky diode is the material it's made from: a multilayer of microscopic crystalline indium selenide.
Representation of indium selenide. Image courtesy of the University of Manchester
These 2D atomic layer heterostructures are referred to as van der Waals. Most van der Waals structures are made from graphene and other carbon-based compounds. According to Gu’s partner, WSU physicist Matthew McCluskey, this material has no impurities or defects at the interface where the metal and semiconductor materials are joined together, which allows electricity to travel through the device with nearly 100% efficiency.
A van der Waals heterostructure. Courtesy of the Kim Group at Harvard University
Dr. Gu’s research was published in the Journal of Physical Chemistry Letters.
Applications and Challenges
Recycling the heat from electronics and automobiles would make for a viable renewable resource that is waiting to be harnessed. If Dr. Gu and his team can find a way to produce the crystalline indium selenide inexpensively, there will likely be a market for it.
Of course, at present, this heat-recycling device is too experimental for anything practical. In an interview, Dr. Gu talked about having it mounted on something like a car exhaust pipe. If it can't fit on an automobile yet, then this design has a long way to go before it can fit into a consumer device, let alone a mobile device.
The crystalline indium selenide used for these diodes sounds very difficult to develop, which could make it too expensive for any consumer products. Dr. Gu’s Associate Dr. Matthew McCluskey has made a start-up company called Klar Scientific, which develops specialized microscopes and other optical instruments in order to refine materials made from van der Waals structures like indium selenide.
A modular scanning confocal microscope with digital image processing like this one is used to view van der Waals. Image courtesy of Washington State University
These van der Waals Schottky diodes would need to collect a lot of energy because we can already charge something like a phone battery using the energy from a car's alternator. This may come in handy down the road for electric vehicles, which can use all the extra electricity they can get to improve their range in order to be more competitive with petrol engines.
Although the odds of commercial success for the technology anytime soon are low, it's hard not to root for a design that can turn a byproduct into electricity. I've compiled a list of other designs in development that convert byproducts into energy below:
Is there an energy producing technology that has you excited? Let us know in the comments!
Featured image courtesy of Nature.com.