German-French scientists develop ultra-thin GaAs solar cell with 19.9% efficiency

Share

A research team from Germany’s Fraunhofer ISE and France’s Centre for Nanoscience and Nanotechnology (C2N) claim to have developed an ultra-thin solar cell based on Gallium arsenide (GaAs), which is a compound of elements belonging to the so-called III-V materials, with an efficiency of 19.9%.

The results, the scientists have explained, were obtained through a new manufacturing process that is characterized by the use of a 205-nanometer-thick absorbing GaAs layer and a nanostructured back mirror. “The guiding idea was to conceive a nanostructured back mirror to create multiple overlapping resonances in the solar cell, identified as Fabry–Perot and guided-mode resonances,” said Fraunhofer ISE.

These resonances are said to trap light in the absorber for a longer time. Simultaneously, they improve optical absorption, which is enhanced over a large spectral range that fits the solar spectrum from the visible to the infrared.

Popular content

The silver back mirror was fabricated at the nanometer scale by soft nano-imprint lithography, through the application of a sol-gel derived film of titanium dioxide. “Controlling the fabrication of patterned mirrors at the nanometer scale was a key in the project,” the research team said.

It also believed that this cell technology could reach a 25% efficiency rate in the short term. It is also thought that the cell’s thickness could be further lowered without efficiency losses. The results of the research were published in “III-V Photovoltaics and Concentrator Technology,” in the scientific journal Nature Energy.

This content is protected by copyright and may not be reused. If you want to cooperate with us and would like to reuse some of our content, please contact: editors@pv-magazine.com.