There have been several noteworthy improvements in solar cell efficiency recently for both thin-film CIGS and silicon. Here’s an overview of the industry’s latest announcements.
We hear a lot these days about how the major advances in solar will come not from technology but from policy, soft cost reductions, or financial innovations. Nonetheless, technology continues to progress. Recently, there have been several noteworthy improvements in solar cell efficiency for both thin-film CIGS and silicon. James Montgomery of Renewable Energy World took a look at the latest in an overview of the recent efficiency advances. He found some improvements in three key areas.
N-type and p-type silicon improvements
Most solar cells use boron-doped p-type silicon. However, n-type silicon is a better-quality material that can achieve higher conversion efficiencies. Fraunhofer ISE has developed a way to create cells with a 24% conversion efficiency — up slightly less than 1% over the past four years.
Meanwhile, imec, another European research center, is pushing ahead with p-type solar cell technology. The institute developed a cell with an average conversion efficiency topping 20.2%.
The Center for Solar Energy and Hydrogen Research (ZSW) in Germany has set a new record for thin-film CIGS by developing a 20.8% efficient cell, up from the multicrystalline solar cells record efficiency of 20.4%. They expect the efficiency of commercial CIGS modules to go up from 14-15% to 16-18% efficiency in about four years.
ZSW is also developing new materials to improve the efficiency of thin-film solar cells that use the more earth-abundant materials tin and zinc.
EMPA, a Switzerland-based institute, has made 20.4% efficiency cells on plastic foils that would allow for more streamlined roll-to-roll manufacturing. Their new record beats their previous milestone of 18.7% by nearly two full points.
Hitting solar PV with sound waves
Researchers at Queen’s Mary University and Imperial College London decided to address the other side of the spectrum: the team hit solar cells with soundwaves to find out what would happen to their power output.
Playing music with different sound pitches affected the cells’ output, with sound levels as low as 75 decibels increasing solar cell efficiency up to 40%. According to the researchers, pop music has the biggest effect because of the cells’ sensitivity to higher-pitched sounds.