According to Die Welt online, a team of German physicists at the Freiburger Fraunhofer Institute for Solar Energy Systems set a new world record by making a solar cell that can convert 41.1% of the sun’s light into electricity. Today’s typical silicium panels on homes don’t even reach 20%.
How did they do it? According to Die Welt, the solar cells have 3 layers stacked on top of each other, each converting a certain part of the sunlight.
In the first layer the visible light spectrum is converted into electricity. The thermal spectrum of sunlight passes through the first layer and is absorbed by a 2nd layer and converted into electricity. Especially longwave infrared light is converted by a third layer.
In addition to the three layers, which are made of elements such as gallium, germanium, indium and arsenic, the cells also have 22 micrometer–thin layers that perform special electrical functions. Physicist Frank Dimroth, who with his team worked 10 years to reach the record, says:
It’s all horribly complicated.
There are other drawbacks. The cells are efficient only in intensive, direct sunlight, which means they will find only a use in dry equatorial regions and will have to be equipped with a sun-tracking system to follow the sun from morning until evening.
They are also very expensive. The manufacturing cost is 50 times more than today’s conventional solar cells. Still, Dimroth hopes that production costs can be brought down to earthly levels by mass production. There’s no mention in the report of recycling and disposal costs.
1. It’s good that they are working on it.
2. Solar cells are NOT the answer for a nation’s energy requirements, but can “help” in limited ways where only limited amounts of low-voltage, low-current DC power is required for limited times of the day where the cost of running conventional lines is too expensive, too impractical.
Typically, you can only get solar power (at 90+ percent theoretical levels) between 10:30 and 13:30 hours local time. Before and after that small window – that period when the sun is almost directly overhead – between about 0900 local and 10:30 and later between 13:30 and 15:00, the amount is much less than maximum even with a (very expensive!) tracking tower and control system. And each morning and evening – you get nothing.
For solar power users, the sun doesn’t shine 12 hours a day, but is usable only about 6 hours.