Hysteretic Piezochromism in a Lead Iodide-Based Two-Dimensional Inorganic–Organic Hybrid Perovskite
Paul Steeger, Mohammad Adnan, Thorsten Deilmann, Xiang Li, Susanne Müller, Katarzyna Skrzyńska, Michael Hanfland, Efim Kolesnikov, Jutta Kösters, Theresa Block, Robert Schmidt, Ilya Kupenko, Carmen Sanchez‐Valle, G. Vijaya Prakash, Steffen Michaelis de Vasconcellos, Rudolf Bratschitsch
Abstract
Two-dimensional inorganic–organic hybrid perovskites are in the limelight due to their potential applications in photonics and optoelectronics. They are environmentally stable, and their various chemical compositions offer a wide range of bandgap energies. Alternatively, crystal deformation enables in situ control over their optical properties. Here, we investigate (C 6 H 9 C 2 H 4 NH 3 ) 2 PbI 4, a hybrid perovskite whose organic linkers are 2-(1-cyclohexenyl)ethylammonium. Pressure-dependent optical absorption and emission spectroscopy reveal a hysteretic piezochromism that was not reported for other lead iodide-based 2D perovskites. We combine our optical studies with high-pressure X-ray diffraction experiments and first-principles calculations to demonstrate that the deformation of the inorganic lead iodide layers is the main reason for the observed changes in the optical bandgap.