Longer perovskite solar cell life after theoretical search of passivating materals

Author: EIS Release Date: Feb 28, 2023

Perovskite materials show much promise in solar cells as they are as efficient as silicon, but are deposited as thin films that can be coated on glass.

 

Yanfa-Yan-credit-Daniel-Miller-University-of-Toledo

However, their lifetime is nothing like as good as silicon, and many research projects are under way to increase durability.

 

This week, the University of Toledo has reported on a project that passivated reactive points in the crystal structure to prevent it failing.

 

It is known that chemicals called Lewis bases can donate electrons and bind with under-coordinated lead (Pb) atoms and passivate defects at interfaces and grain boundaries in perovskite films.

 

With this knowledge, the research team used density functional theory to screen potential such bases and found the one most likely to bond strongly to Pb.

 

They found the di-phosphids 1,3-bis(diphenylphosphino)propane, a commercially-available chemical, which did indeed stabilise the perovskite solar cells they were dealing with.

 

“Phosphine-containing Lewis base molecules with two electron-donating atoms have a strong binding with the perovskite surface,” said Toledo physics professor Yanfa Yan (pictured). “We saw the robust beneficial effects on perovskite film quality and device performance when we treated the perovskite solar cells.”

 

Once stabilised, the cells operated at ~23% efficiency for >1,500 hours (85°C open-circuit). ~23% was also achieved for for >3500 hours at ~40°C at maximum output with simulated AM1.5 illumination.

 

The next step is to try the same technique in the construction of whole solar panels.

 

The University of Toledo collaborated with the University of Washington, University of Toronto, Northwestern University and Swiss Federal Laboratories for Materials Science and Technology.