Dr Gavin Bell and Dr Yorck Ramachers working on the solar power device in the laboratoryA new solar power device similar to a thin double-glazed window has been developed by two scientists at the University of Warwick in the UK. The device uses gas instead of vacuum to collect and transport electrical energy, and could lead to the development of more advanced photovoltaics for solar power.
The pair, Gavin Bell and Yorck Ramachers, whose study was published in the journal Joule [Bell, G. R. and Ramachers, Y. A., Joule (2017) DOI: 10.1016/j.joule.2017.11.007], realized that some materials physics combined with modified particle physics detector technology could form the basis of an energy system or a light-sensing device. The pair were re-investigating concepts around the photoelectric effect for solar power generation that go back to the time of Nikola Tesla and Albert Einstein.
Their breakthrough is based on solar power generation as opposed to traditional photovoltaics, whose efficiency are difficult to improve on. As Gavin Bell said “Our device is radically different from standard photovoltaics, and can even be adapted for other green technologies such as turning heat directly into electricity”. The outer pane of the device is transparent and can conduct electricity, while the inner window is coated with a material that acts a source of electrons under illumination by sunlight, called a "photocathode".
“Our device is radically different from standard photovoltaics, and can even be adapted for other green technologies such as turning heat directly into electricity”Gavin Bell
The panes are separated by a safe inert gas, such as argon. On sunlight striking the device, electrons are knocked from the photocathode to bounce through the gas to the outer pane without being absorbed or lost, which is very different to the way electrons usually act in solar panels. The electrons are then collected and the electrical energy transported into the grid through a gas-filled gap instead of a vacuum, making it much more cost-effective.
The team still have to work out the best material for the photosensitive layer, with a number of candidate materials being proposed – such as thin films of diamond, which would be extremely robust and long-lasting. In addition, the photocathode’s transparency could be changed, perhaps offering tinted windows that can generate solar power.
The findings show the potential for photoelectric solar power on a more quantitative basis, and highlight the transport of low energy electrons through atmospheric pressure gas, something of interest in energy research. The main applications lie in solar power generation if the materials challenges can be resolved, as well as thermionic power conversion and ultraviolet detection technologies. The team also hope that the materials science community will be inspired by the idea to further investigate photocathodes working in inert gas rather than vacuum.