Tin continues to flex its muscles as a safer alternative to lead. First there was the shift from lead-based solder to tin-based solder. Now tin has been flagged as the best substitute for lead in solar cell technology.

A new solar cell developed by two separate teams of researchers promises low-cost, enhanced efficiency and a smaller environmental footprint.

The new cell uses a perovskite structure composed of tin instead of lead as the light-absorbing material in a perovskite solar cell. A perovskite structure’s usefulness in solar cells was discovered in 2009 using lead as the primary structure, but researchers have now demonstrated successful perovskite solar cell technology using tin.

Tin is the ideal material because unlike lead, it is a low-toxicity metal and is not easily absorbed by the human body.

Tin perovskite structure offers the potential economic advantage of being cheap and easy to make. It can be simply integrated into a standard manufacturing process.

The tin solar cell currently has an efficiency of around 6 per cent. Efficiency of a solar cell is measured as a percentage of sunlight absorbed versus the amount converted into energy. Tin has lower efficiency than lead, which reaches 15 to 16 per cent. However, researchers are encouraged by the fact that in 2009, lead perovskite structures were only at 3.8 per cent and they expect that tin will eventually be able match that efficiency.

Lead researcher Mercouri G. Kanatzidis, an inorganic chemist with the Weinberg College of Arts and Sciences at Northwestern, as reported in Nature Photonics, said “There is no reason this new material can’t reach an efficiency better than 15 percent,”

“Tin and lead are in the same group in the periodic table, so we expect similar results.”

If tin perovskites mimic the pattern set by lead, researchers will have brought a non-hazardous recipe of materials to a very promising technology.

The technology will still have to be demonstrated outside the laboratory and be proven to be affordable and durable at a commercial scale.

Source: Climate Spectator