Solvent switch adds stability to perovskite solar cells

By removing the solvent dimethyl-sulfoxide and introducing dimethylammonium chloride as a crystallisation agent, the researchers at Oxford University and Exciton Science were able to better control the intermediate phases of the perovskite crystallisation process, leading to thin films of greater quality, with reduced defects and enhanced stability.

Large groups of up to 138 sample devices were subjected to an accelerated ageing and testing process at high temperatures and in real-world conditions.

Formamidinium-caesium perovskite solar cells created using the new synthesis process are said to have significantly outperformed the control group and demonstrated resistance to thermal, humidity and light degradation.

According to the team, this is a strong step forward to matching commercial silicon’s stability and makes perovskite-silicon tandem devices a much more realistic candidate for becoming the dominant next-generation solar cell.

Led by Oxford’s Professor Henry Snaith and Professor Udo Bach, Monash University, Australia, the work has been published in Nature Materials.

In a statement, Oxford University PhD student Philippe Holzhey, a Marie Curie Early Stage Researcher and joint first author on the work, said: “It's really important that people start shifting to realise there is no value in performance if it's not a stable performance.