Next-generation solar cells based on perovskite are lighter than conventional silicon-based modules, making installation simpler with lower load-bearing requirements for rooftops. But perovskite cells are difficult to manufacture at scale and have a slightly reduced efficiency at 24.2% vs 26.7% for silicon.
PEDOT, a new polymer developed at MIT, can be integrated into the panels to create a transparent conductive layer that’s less brittle than indium titanium oxide, which is transparent and conductive, but brittle and susceptible to cracking.
The combined transparency and conductivity is measured in units of Siemens per centimeter. ITO ranges from 6,000 to 10,000, and though nobody expected a new material to match those numbers, the goal of the research was to find a material that could reach at least a value of 35. The earlier publication exceeded that by demonstrating a value of 50, and the new material has leapfrogged that result, now clocking in at 3,000; the team is still working on fine-tuning the process to raise that further.
The findings were published this month in the journal Science Advances.
Many panels use indium titanium oxide for protection, but it’s brittle and susceptible to cracking. The team developed a PEDOT alternative two years ago, but it lacked ITO’s transparency and conductivity. The new material is 10 times more conductive than the old one, edging toward ITO levels, and lab tests showed it was able to boost a perovskite cell’s efficiency and stability.
Perovskites have been cited by the International Renewable Energy Agency as one of the technologies that could help solar meet the world’s energy needs. The agency’s report, posted earlier this month, stated that deploying solar alone could reduce carbon dioxide emissions 21 percent by 2050. That would mean solar covers 25 percent of global energy, second only to wind, and could contribute to a 70 percent reduction in carbon emissions from 2020 levels.
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