Can the most exciting new solar material live up to its publicity?

While Perovskites have the power to reach high efficiency ( world record for a cell with only perovskite it is something more than 25%), now most of the best yields among perovskite cells are small – less than an inch wide.

Increasing the scale makes it difficult to reach the limits of potential efficiency. Right now, Saule’s one-meter-wide panels are 10% more efficient. This is reduced by commercial silicon panels of a similar size, which typically achieve an efficiency of 20%.

Olga MalinkiewiczAccording to Saul’s founder and chief technology officer, the company’s goal was to extract only one solar cell from perovskites, and that low efficiencies won’t matter if the technology is cheap enough.

Saule is trying to get where silicon solar panels don’t want to go: to covers that can’t withstand the weight of heavy glass-covered panels or to more specialized applications, such as solar blinds, for cases the company is testing.

While Saule is marketing thin film products for more niche applications, other companies expect silicon to gain or at least merge in its game. Based in the UK Oxford PV perovskites are entering combination perovskite-silicon cells.

Because silicon absorbs light to the red end of the visibility spectrum, and perovskites are tuned to absorb different wavelengths, coating a layer of perovskite on silicon cells allows the combination cells to achieve greater efficiency than silicon.

Oxford PV combination cells are heavy and rigid, like silicon-only cells. But because they are the same size and shape, new cells can easily be inserted into roof matrix panels or solar panels.

Chris Case, Chief technology officer at Oxford PV, says the company is focused on lowering the standard cost of electricity by factoring in the costs of installing a system and operating it for a lifetime. While the stratification of perovskites on silicon adds to the manufacturing cost, he says the equal cost of the combined cell should fall below that of silicon over time because these new cells are more efficient. Oxford has registered several world brands in recent years for the effectiveness of this type of cell, which eventually reached 29.5%.

Semiconductor Microquanta, A Chinese perovskite company based in Hangzhou is also taking some signals from silicon solar cells. The company is manufacturing from rigid glass-coated cells made of perovskite.

The pilot plant for Microquanta opened in 2020 and should reach a capacity of 100 megawatts by the end of the year, he says Buyi Yan, head of technology at the company. The company has installed display panels in various buildings and solar farms across China.

Stability solution

Perovskite’s stability has improved from a few minutes to a few months in a matter of years. But most of the silicon cells currently installed have a 25-year warranty, a goal that perovskites still can’t achieve.

Perovskites are particularly sensitive to oxygen and moisture, as they can interfere with crystal bonds, preventing electrons from moving efficiently through the material. Researchers have been working to improve the life of perovskites, both by developing less reactive perovskite and by looking for better ways to package them.

Oxford PV, Microquanta and Saul say they have solved the stability problem by at least the age of selling the first products.

Calculating long-term performance in solar cells is usually done through accelerated testing by placing cells or panels under stress-free conditions to simulate years of wear. The most common set of external silicon cell tests is the IEC 61215 series.