Cheaper solar cells

A new design for solar cells that uses cheaper and more common materials could rival and maybe outperform conventional cells made of silicon.

Study co-author Michael McGehee said “Perovskite semiconductors have shown great promise for making high-efficiency solar cells at low cost,” He also said “We have designed a robust, all-perovskite device that converts sunlight into electricity with an efficiency of 20.3 percent, a rate comparable to silicon solar cells on the market today.” The new device consists of two perovskite solar cells stacked in tandem. Each cell is printed on glass, but the same technology could be used to print the cells on plastic, McGehee added.

Co-author Henry Snaith, a professor of physics at Oxford said “The all-perovskite tandem cells we have demonstrated clearly outline a roadmap for thin-film solar cells to deliver over 30 percent efficiency,” he also said that “This is just the beginning.”

Seeking stability

A concern with perovskites is it stability. Rooftop solar panels made of silicon can typically last 25 or more and are always installed by roof experts from sites as The problem wit perovskites is it degrades quickly when exposed to moisture or light. In previous experiments, perovskites made with tin were found to be particularly unstable.

To check the stability, the research team subjected both experimental cells to temperature of 100 degrees celsius for four days. “Crucially, we found that our cells exhibit excellent thermal and atmospheric stability, unprecedented for tin-based perovskites,” the authors wrote.

McGehee said “The efficiency of our tandem device is already far in excess of the best tandem solar cells made with other low-cost semiconductors, such as organic small molecules and microcrystalline silicon,” Snaith said that “the next step is to optimize the composition of the materials to absorb more light and generate an even higher current,” Snaith also added that “The versatility of perovskites, the low cost of materials and manufacturing, now coupled with the potential to achieve very high efficiencies, will be transformative to the photovoltaic industry once manufacturability and acceptable stability are also proven,”