Sungkyungwan University Professor’s Team Invents Cleaning Process for Perovskite Solar Cells at Room Temperature
 
Expired solar cells can be recycled by being cleaned.
 
On June 14th, a team lead by Dr. Hyunsuk Jung, a professor of Advanced Materials Science and Engineering at SKKU, invented a recycling process for perovskite solar cells that can be performed effectively at room temperature.
Organic-inorganic perovskite light absorber has high light absorption coefficient, so their world-record photoconversion efficiency reached up to 22%, even when it is below 500nm (nanometer, 1nm = one billionth of a meter) in thickness. They not only surpass the efficiency of silicon solar cells, which have the same thickness as perovskite cells, but are also receiving attention because they do not require expensive high-temperature high-pressure processes.
 
However, scientists were apprehensive about perovskite solar cells because the expired ones accumulate lead in their absorber layers which might adversely affect human beings and the environment during their dismantling process. They were also difficult to distribute due to the fact that materials composed of perovskite solar cells like transparent conductive layers are precious metals like gold.

The research team solved the aforementioned problems by dissolving perovskite solar cells in a polar aprotic solvent like dimethylformamide (DMF) enabling them to get transparent conductive substrate once the lead absorber layers were removed above 99.99%. They were able to pick up the substrates because they sank in the solvent used for electrodes.

Byeongjo Kim, the 1st co-author of the thesis, said, “After the solution process, the transparent conductive substrate emerged in seconds. The polar aprotic solvent successfully removed the lead from the perovskite’s absorber layers.”

Also, the team discovered that the solar cells could be recycled by cleaning the transparent conductive substrates. The research team confirmed that they had the same level of function as new solar cells.
Dr. Jung said, “This invention is quite meaningful because it solved the environmental problems associated with perovskite solar cells and created a new way to raise their economic efficiency.”
 
The results of this study were published in Nature Communications along with Nature Scientific Journal on May 23rd.