Tailoring structural transitions in layered 2D perovskites using light

Organic-inorganic (hybrid) perovskite have recently emerged as a new semiconductor platform for next generation optoelectronics devices. These perovskite solids feature weak bonds between their organic and inorganic building blocks, which results in an intrinsic softness and dynamics disorder of the lattice and an acute sensitivity to external stimuli. For example, our group demonstrated that continuous sunlight illumination leads to a uniform expansion of the perovskite lattice, which impact the optoelectronic properties of the three-dimensional perovskites. In particular, this effect is beneficial as it helps cure electronics impurities and lowers energetic barriers near the surface/interface. Here, we present comprehensive in-situ light induced structural dynamics to layered two-dimensional (2D) hybrid perovskites. We correlate the changes in the structure of the 2D perovskite to modification of both the physical properties and the figures of merit in solar cells. We propose a new microscopic model to explain the evolution of the structure and optoelectronic properties under an external stimulus. These results demonstrate that structural characterization of hybrid perovskite under external perturbation is key in unraveling the fundamental physics of these materials.