In recent years, solar energy has been a hot topic all over, as the world begins looking at alternative and more efficient sources of energy to coal and oil, and we have done a few articles on solar power in the past. Solar energy has been very limiting due to the fact that it has largely until now at least been very inefficient compared to other energy sources.
That all seems to be changing now, as Stanford University has made a breakthrough in solar technology that could once again revolutionize the industry, bringing in a whole new level of efficiency. By taking a different approach, they have now created a system whereby it is not only the energy from the sun’s light that is harvested, but also the heat. Until now a lot of research has been focussing on harvesting energy from the sun’s light, but, the new technology from Stanford University actually combines light and heat – a totally new concept in solar energy. And the figures are quite impressive.
Stanford engineers believe that by using this new method, more than double the amount of energy could be harvested, in comparison to current normal solar cells. According to Stanford’s webite, this new technology called “photon enhanced thermionic emission” (PETE) could reduce solar energy production costs so much that it may be able to compete with an energy source such as oil.
Current solar technology becomes less efficient the more the temperature rises, so it seems like a catch-22 situation. You need the sun to produce power from solar panels, but the irony is that the hotter it gets, the less effective the solar panels become. This new process, (PETE) actually works better, the more the temperature rises. So the hotter it gets, the better it works. According to the University’s website the process will surpass the efficiency levels of current existing photovoltaic and thermal conversion technologies.
“This is really a conceptual breakthrough, a new energy conversion process, not just a new material or a slightly different tweak,” said Nick Melosh, an assistant professor of materials science and engineering, who led the research group. “It is actually something fundamentally different about how you can harvest energy.”



With normal photovoltaic cells, the semiconducting material used (silicon) can only use a portion of the light spectrum. The unused sunlight is therefor turned into heat, and is lost. This loss of energy amounts to about 50 percent of the initial solar energy that reaches the cell. The engineers found that by coating a coating a piece of semiconducting material with a thin layer of the metal cesium, they were able to harvest the energy generated from both light and heat, and thus turn it into electricity.
Most solar cells become highly ineffective when reaching a temperature of 100 degrees celsius, but the new PETE device only hits it maximum performance peak at over 200 degrees celsius. Now, because rooftops are highly unlikely to reach these kinds of temperatures th PETE device wil work best in situations where the light can be focussed, in cases such as parabolic dishes, where temperatures can rise to as much as 800 degrees Celsius.
It is estimated that by using PETE, the energy produced could be almost three times as much as existing systems produce at the moment. The engineering team wish to design PETE devices so that they could be easily integrated with existing systems.