used the LIFEtime 2DIR instrument at Ultra to investigate how this material’s
components move and interact over time.
Hybrid perovskites are a relatively complex material that contain both an organic and inorganic part. The organic part typically consists of relatively small – less than 10 atoms – cations, whilst the inorganic part creates a cage around these organic cations to keep them in place. Hybrid perovskites are semiconductors. They combine the advantages of organic semiconductors (low cost and flexibility) with the advantages of inorganic semiconductors (high performance and electrical conductivity). Their composition is what gives them the properties to be a suitable candidate for solar cell applications.
The organic cations can interact with the inorganic cage they sit in and move within that cage by 'rotating'. This movement and interaction influences properties of the material that are relevant to their applications as solar cells. However, very little is known about how the interactions influence the properties of the material and how they might be controlled to improve solar cell applications.
Therefore, a team of researchers used the LIFEtime 2DIR instrument at Ultra to build up a real-time picture of how the organic cations rotate and how their interaction with the inorganic part of the structure changes over time. This will help us better understand how the interactions between the organic cations and their inorganic cages influences the properties of hybrid perovskites. This in turn will hopefully enable us to improve their material applications as next generation solar cells.
Measurements were done across a series of hybrid perovskites with increasing amounts of the organic cation swapped out for caesium. This changed the shape of the inorganic cage but not the composition of the cage itself. This allowed the researchers to keep aspects of the interactions they're interested in constant.
They discovered that the two rotational processes the organic cation can perform inside of the cage depend on different types of interactions with the inorganic cage. By looking at the rotations and interactions at the same time, the scientists can better understand how these interactions change over time, therefore how they effect the solar cell performance of the material.
Read the paper detailing this research into hybrid perovskites using LIFEtime 2DIR at Ultra.