Advanced molecular simulations to unravel phase transformations of perovskites

Perovskites have garnered intensive interest because of their extraordinary properties for photovoltaic applications. In the last years, the maximum obtained efficiency of perovskite absorbers for this application has risen substantially, up to a maximum of 23%, thereby rapidly closing the gap with the efficiency of more traditional photovoltaic materials. The further development of these perovskites for photovoltaic applications is, however, hampered by their limited mechanical and chemical stability. For instance, experiments at ambient conditions reveal that the desired black phase of inorganic perovskites tends to transition towards a yellow nonperovskite phase, which is associated with a strong deterioration of the photovoltaic properties. To understand how this unwanted phase transition can be suppressed, it is crucial to acquire microscopic insight into the physical interactions underpinning the stability of these materials. In this project, we will therefore develop and apply advanced simulations at the molecular level to model and comprehend the driving force for these phase transitions. This in-depth understanding will enable to computationally design and afterwards experimentally synthesize perovskites with an exceptional stability and superior photovoltaic performance exceeding the current state of the art.