PETE could be your new best friend if you're thinking of installing solar panels. PETE's not actually a person but a new solar energy capture technology that's just been announced by scientists at Stanford University.
The new technology, photon-enhanced thermionic emissions or PETE concentrates solar energy on a semiconductor receiver coated with cesium metal. It's twice as efficient as existing solar panels as it combines both the light and heat from solar radiation to produce electricity.
Current photovoltaic cells used in solar panels convert the energy of light photons to electricity using silicon as a semiconducting material. Unfortunately, they can only use part of the light spectrum with the rest of it just generating heat. The problem has been to capture this wasted heat energy, which can account for up to 50 per cent of the solar energy received by the cell.
Conventional solar panels become less efficient as the temperature rises, but high temperatures are needed to capture the wasted heat energy. The new solar cells work all the way up to 800 degrees centigrade, rather than the 100 degrees centigrade of conventional photovoltaic cells. Their peak efficiency starts at well over 200 degrees centigrade. In fact, the hotter, the better for the performance of PETE cells. It's the cesium coating that makes the big difference as it enables the semiconducting material to harvest the energy from both the heat and light.
Just as exciting as the increased efficiency of PETE, is the potential for reducing the costs of solar power technology. As it uses solar concentrators, PETE uses less semiconducting material, so the need for large expensive sheets of silicon should become a thing of the past. The Stanford University team also want to design devices so that the new technology can be easily added to existing systems.
Also other materials, such as the commonly-used gallium arsenide, could work even better than the gallium nitride semiconducting material that the team used.
This is a fundamentally-new way of generating solar panels. Hopefully, it'll be standard fitment in homes in the next few years.
