A decade of research has gone into raising the efficiency of perovskite solar cells to the level of conventional silicon solar cells. The alternative technology is widely considered to be the future of photovoltaics as the cells can be produced easily, cost-effectively and with a high degree of sustainability. But the problem is, they don’t last long.
"The Achilles' heel of perovskite solar cells is their low durability," explains Prof. Christoph Brabec of the Helmholtz Institute Erlangen-Nuremberg (HI ERN) at the Jülich Research Centre in a . "Classic silicon modules are quite durable. Even after more than 20 years in practical use, they lose little of their performance." By contrast, perovskite cells typically lose efficiency after weeks or even days, which means they are not yet commercially viable.
But all this could soon change: Prof. Brabec’s team at HI ERN have developed new perovskite variants in the laboratory with ultra-long stability. During testing, the illuminated cells were able to withstand temperatures of 65°C, over 1,450 hours, and remained remarkably stable – retaining 99 percent of their initial efficiency.
The HI ERN team achieved the results, which were first published in the journal , by testing hundreds of perovskite mixtures before hitting on the right formula. They also shielded the electrodes with a protective shell to improve stability at the points of contact. Brabec is confident that the new variant “could be operated for more than 20,000 hours under normal circumstances.”
“The solar cell we have now presented in Nature Energy impresses with its exceptional stability,” he says. “The values are certainly among the best ever measured for a planar perovskite solar cell in a long-term test.” The next goal is to improve the efficiency of the cells from 20.9 percent to 24 or 25 percent, approaching the efficiency of conventional silicon solar cells.