Presentation description

Metal halide perovskites have emerged as promising new materials in the field of photovoltaics. They can be used in a number of optoelectronic devices such as LEDs and solar panels. Recently, researchers have taken advantage of their ability to store heat for solid state refrigerants and insulation materials. We focus on 2D Ruddlesden-Popper (RP) perovskites that have alternating inorganic and organic layers, where a metal cation and a halide anion make up the inorganic layers that sandwich the organic spacer cations. Because of the way RP perovskites are structured, they can undergo a solid-solid phase transition where the organic layer ""melts,"" but the inorganic layers remain solid, thus allowing the material to undergo a phase transition but remain a solid. This phase change can be fine-tuned by changing the organic cation. Using X-ray diffraction (XRD) and temperature dependent grazing incident wide angle X-ray scattering (GIWAX), we calculated the lattice spacing and the phase transition temperature of nonylammonium copper (II) bromide ((NA)¬2CuBr¬4), decylammonium copper (II) bromide ((DA)2CuBr4), and dodecylammonium copper (II) bromide ((DDA)2CuBr4). We observed changes in the crystal lattice spacing as well as shifts in the phase transition temperatures depending on the length of the organic cations.