Black Silicon solar cell efficiency pushed to 22.1%

The sun puts out all the clean and free electricity that we could ever need and the big problem in harnessing it is the low efficiency of solar panels today. Much of the solar energy that hits solar panels in use today isn't turned into electricity. Researchers are constantly working to improve solar panel efficiency and recently researchers from Aalto University and Universitat Politecnica de Catalunya have set a new record for the most efficient solar panel.

The team created a solar panel that uses black silicon with an efficiency of 22.1%. That may not seem like a very high efficiency rating, but it is almost an 4% absolute increase to the previous record for efficiency. The team was able to achieve this record by applying a thin passivating film on the nanostructures using Atomic Layer Deposition.

Efficiency was also aided by integrating all metal contacts on the back of the solar cell. The record setting solar panel has a thick back-contacted structure that is known to be highly sensitive to the front surface. This panel design marks the first time that the black silicon isn't limiting the final energy conversion frequency according to the team.

The team of researchers next plans to apply this same technology to other cell structures including thin and multi-crystalline cells. One researcher involved in the project thinks that higher efficiencies can be achieved by using n-type silicon or more advanced cell structures.