Hao Zhang demonstrated a direct visualization of the carrier-lattice interactions in 2D halide perovskites for the first time. He did this by directly probing the lattice degrees of freedom in ps time scale using the ultrafast electron diffraction technique (MeV-UED) following the above bandgap high-density photoexcitation.
Upon illumination, he observed a novel lattice behavior involving the ultrafast relaxation of lattice distortion, originating from the strong interaction between electron-hole plasma and crystal lattice.
https://news.rice.edu/news/2023/researchers-can-see-crystals-perform-their-dance-moves