Researchers at the Universities of Cambridge and Milan (Politecnico di Milano) investigated the speed at which electrons (created as sunlight hits perovskite solar cell) need to reach the cell’s electrode to be converted into flowing electric current before their energy starts to decline. The scientists found that perovskite solar cells will need to take advantage of femtosecond events (about a millionth of a billionth of a second) to stretch the limits of their energy conversion efficiency.

If the cells manage to work that fast, they could achieve an efficiency of 30% or maybe even more, which is currently thought to be the greatest efficiency that solar cells could achieve. Today’s best silicon-based solar cells typically operate at efficiencies closer to 20%, but perovskite cells are thinner and regarded as having potential to surpass silicon cells' efficiency.

Toshiba recently announced the fabrication of a film-based perovskite solar cell mini module with an impressive conversion efficiency of 10.5%. This efficiency rate was achieved in a 5 cm x 5 cm module and is stated by the company to be the highest yet recorded in a multi-cell mini module.

Toshiba achieved this by developing a fabrication process technology for film-based perovskite solar cells. The technology uses a film substrate and scribe process technology based on organic thin film solar cell module fabrication. Since this technology uses a flexible film substrate, it allows roll-to-roll fabrication that reduces costs. Toshiba will continue to refine the technology and expects to see further improvements in efficiency.