University of Toronto

First Solar and its cadmium telluride (CdTe) technology dominate thin-film solar in the mainstream market. Valerie Thompson looks at the US-based business and the future of thin-film PV technology.

The perovskite solar race is heating up, with a cue of manufacturers forming to test products at the US Department of Energy’s (DoE) PV commercialization facilities, and academics on both sides of The Pond announcing new advances in recent months.

A US-Canadian group of scientists has used Lewis base molecules to improve surface passivation in a perovskite solar cell. The team produced a device with a high open-circuit voltage and remarkable stability levels.

Scientists in Canada fabricated a perovskite solar cell based on an inverted structure that achieved 23.9% efficiency, and maintained 92% of its initial performance after 500 hours of accelerated aging tests. By carefully controlling the thickness of the perovskite layer, the group was also able to gain control of “quantum mechanics” properties such as the movement of electrons within the layer and the wavelengths of light absorbed.

Perovskites and quantum dot solar cells both have potential for use in high efficiency PV devices, but have major challenges to overcome to be a commercial reality. Scientists at the University of Toronto have found that if the two technologies are combined in the right way, they can stabilize each other.