Perovskite solar cell made with the new solvent system. Image: Nakita Noel/Bernard Wenger.
Perovskite solar cell made with the new solvent system. Image: Nakita Noel/Bernard Wenger.

Scientists at Oxford University in the UK have developed a solvent system with reduced toxicity that can be used in the manufacture of perovskite solar cells, clearing one of the barriers to the commercialization of a technology that promises to revolutionize the solar industry.

Perovskites – a family of materials with the crystal structure of calcium titanate – have been described as a 'wonder material' and shown to be almost as efficient as silicon in harnessing solar energy, as well as being significantly cheaper to produce.

By combining methylamine and acetonitrile, the scientists were able to develop a clean solvent with a low boiling point and low viscosity that quickly crystallizes perovskite films at room temperature and could be used to help coat large solar panels with the material. The scientists report their work in a paper in Energy & Environmental Science.

“At the moment, there are three main solvents used in the manufacture of perovskite solar cells, and they are all toxic, which means you wouldn't want to come into contact with them,” explained lead author Nakita Noel from Oxford University's Department of Physics. “Additionally, the most efficient perovskite solar cells are currently made through a process called solvent quenching – a technique that is not easily transferred from lab-scale deposition techniques to large-scale deposition techniques. While vapor deposition of these materials can overcome this problem, it will come at additional costs. One of the main selling points of this material is that it is cheap and can be easily solution-processed.”

“We have now developed the first clean, low-boiling-point, low-viscosity solvent for this purpose,” he continued. “What is really exciting about this breakthrough is that largely reducing the toxicity of the solvent hasn't led to a reduction in the efficiency of the material in harnessing solar energy.”

In recent years, perovskite-based solar cells have raced to the front of emerging photovoltaics, already able to compete on efficiency against well-established solar technologies such as the inorganic thin-film and multi-crystalline silicon used in solar panels around the world. Perovskites also have the shortest 'energy payback time' – the time taken for a material to save the same amount of energy that was expended in its production.

“While we are probably still a few years from seeing perovskite-based solar panels on people's roofs, this is a big step along the way,” said co-author Bernard Wenger, also from the Department of Physics.

Henry Snaith, senior author of the paper and leader of the photovoltaics group at Oxford, has been a pioneer in the development of perovskite solar cells and was one of the first researchers to recognize their potential as a low-cost, highly efficient material for this purpose.

This story is adapted from material from Oxford University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.