Abstract:
Hybrid lead halide perovskites and their derivatives are important optoelectronic materials but suffer from water instability. Combining both the optoelectronics and the water stability of such systems is a major challenge in material design today. To address this issue, we employ the well-known π-conjugation and cation−π interaction concepts in designing a hybrid lead halide perovskite derivative system. (4,4′-VDP)Pb2Br6 (VDP = vinylenedipyridinium) single crystals are prepared. They have a one-dimensional (1D) arrangement of inorganic Pb–Br sublattices connected via the 4,4′-VDP organic sublattice. The π-conjugation in the 4,4′-VDP sublattice allows electronic communication between the 1D Pb–Br units, reducing the band gap and improving the photoconductivity. Importantly, N+ of one 4,4′-VDP molecular ion interacts with the π-electron cloud of the adjacent one. This intermolecular cation−π interaction extends throughout the organic sublattice, making the hybrid crystal stable when stored under water for more than a year without requiring any encapsulations.