Structural and Optical Properties of a 0D Lead Iodide Hybrid Perovskitoid with Aromatic Diammonium Cations

0D hybrid organic–inorganic perovskitoids (HOIPs) are promising candidates for optoelectronic applications, due to the properties arising from the isolation of the metal halide octahedra, such as broadband photoluminescence (PL) emission, ambient stability, and reduced ion migration. However, a better understanding of the role of the organic cation in the crystal phase formed and resulting optical properties is needed, particularly regarding the appearance of anisotropy in the arrangement of the octahedra in the lattice. Here, the synthesis, crystal structure, and optical, vibrational, and electrical properties of a new 0D lead iodide HOIP containing 3-(aminomethyl)pyridinium, 3AMPy, as organic cation, are presented. X-ray diffraction reveals that 3AMPy2PbI6 has an orthorhombic crystal structure consisting of isolated [PbI6]4− octahedra. Polarization-dependent Raman spectroscopy and optical microscopy reveal narrow modes with preferential crystal orientation and birefringence, respectively. 3AMPy2PbI6 exhibits an isotropic red broadband PL emission shifted to longer wavelengths compared to the 2D and 3D AMPy-PbI2 phases and to other 0D Pb-based HOIPs, which is ascribed to exciton recombination and trap states in the octahedra. Devices made with flakes of 3AMPy2PbI6 show photoconduction under 405 nm light. Our results provide insight into the structure and optical properties of 0D HOIPs and their potential in optoelectronic devices.