Lead Halide Perovskites

In the past decade, organic-inorganic perovskite materials have captured the attention of the scientific community due to their high potential for application in photovoltaic devices. This unique class of materials offers superb optoelectronic properties similar to GaAs, including extremely low degree of energetic disorder and high yield of photoluminescence (PL) quantum efficiency despite being processed from solution at low temperatures. They also exhibit extremely high exciton and carrier diffusion lengths and high absorption coefficients. The combination of these properties results in excellent performance in photovoltaic devices, reaching >25% to date.

Despite their phenomenal properties and remarkable performance, several challenges prevent their large-scale integration into industrial applications. In our group we focus on addressing these challenges and developing mitigation strategies to resolve them.

Stability: The relatively low stability of perovskite materials and devices is a significant limitation to their future application. We investigate the influences of environmental factors such as O₂, H₂O or light on the properties of perovskite materials. Additionally, we are interested in identifying the role that defects play in determining the stability of perovskite materials and devices.

Ion migration and hysteresis: The mixed electronic-ionic nature of perovskite materials dictates that not only charge transport, but also ion transport takes place in perovskite materials. The transport of ions has been linked to the presence of hysteresis in perovskite photovoltaic devices and has been shown to increase their degradation. We investigate the migration of ions both experimentally and by numerical simulations in order to understand the fundamentals of this process and its effect on the performance and stability of perovskite devices.

Reproducibility: Perovskite devices are notoriously known to suffer from poor reproducibility. We investigate the various factors that influence the properties and performance of perovskite devices in order to develop more robust and reliable fabrication procedures.