Layered hybrid perovskites exhibit a wide range of physical properties and exceptional functionality. However, the coexistence of lattice order and structural disorder poses challenges for understanding these materials from a materials science perspective. The manipulation of inorganic frameworks and interactions with molecular moieties can affect lattice dynamics, but the underlying process remains unknown.
To tackle this issue, Zhuquan Zhang and a team of scientists from the University of Pennsylvania, University of Texas, Austin, and the Massachusetts Institute of Technology, U.S., employed a combination of spontaneous Raman scattering, terahertz spectroscopy, and molecular dynamics simulations.
The research findings unveiled how the structural dynamics, both in and out of equilibrium, offer unexpected observables that can distinguish between single- and double-layered perovskites. The study has been published in Science Advances.
Although no vibrational coherence was observed in double-layered perovskites, the researchers noted the potential for an off-resonant terahertz pulse to induce a long-lived coherent phonon mode in the single-layered system. These findings based on layered perovskites have implications for ultrafast structural engineering and high-speed optical modulators.
Over the past two decades, materials scientists have highlighted the significance of two-dimensional hybrid perovskites as natural, quantum-well-like semiconductors with notable light absorption, high luminescence quantum yield, and strong exciton binding energy. Compared to their 3D counterparts, these materials offer a wide range of chemical variability and structural diversity, and their composition can be adjusted by modifying organic spacer cations, inorganic networks, and octahedral layers.
2023-09-01 07:00:04
Original from phys.org rnrn