Regulating the Intermolecular Hydrogen Bond to Realize Directional Dimension Reduction of Lead Iodide Perovskite toward Low-Dimensional Photovoltaics

A low-dimensional organic amine lead halide perovskite is an attractive semiconductor material that has potential application prospects in photovoltaics, light-emitting diodes, detectors, X-ray imaging, and other fields. It has been reported that the photoelectric properties of low-dimensional perovskite can be controlled by adjusting the chain length of organic ammonium, the ratio of precursor components, and van der Waals interaction between amine molecules. Herein, we report the successful synthesis of low-dimensional perovskite (PdEA)PbI4 (PdEA = piperidine ethylammonium) and (MlEA)PbI4 (MlEA = morpholine ethylammonium) single crystals by regulating the intermolecular hydrogen bond of organic ammonium ligands. The two-dimensional (2D) layered structure (PdEA)PbI4 single crystal with a fluorescence reflection peak at 563 nm was produced by the reaction of PdEA with PbO in a concentrated hydroiodic acid aqueous solution. Differently, the (MlEA)PbI4 single crystal prepared by replacing MlEA with PdEA presents a one-dimensional (1D) rod structure, and its fluorescence reflection peak is located at 531 nm. The optical bandgaps of (PdEA)PbI4 and (MlEA)PbI4 perovskite films were about 2.16 and 2.33 eV, respectively. Low-dimensional perovskite solar cells with 2D (PdEA)PbI4 and 1D (MlEA)PbI4 of perovskite films yielded efficiencies of 1.18 and 1.52%, respectively.