Bromine-Substitution-Induced High-T_c Two-Dimensional Bilayered Perovskite Photoferroelectric

Abstract

High-Curie-temperature (T c) ferroelectrics have exhibited broad applications in optoelectronic devices. Recently, two-dimensional multilayered perovskite ferroelectrics with excellent photoelectric attributes are attracting increasing interest as new systems of photoferroelectrics. However, the effective tuning of the T c value of a multilayered perovskite photoferroelectric system still remains a huge challenge. Here, by a halogen substitution strategy to introduce bromine atoms on n-propylamine cations, the hybrid perovskite photoferroelectric (3-bromopropylaminium)2(formamidinium)­Pb2Br7 (BFPB) with a high T c value (348.5 K) was obtained. It is notable that BFPB adopts a two-dimensional bilayered inorganic framework, with tight linking to the organic cation by C–Br···Br–Pb halogen···halogen interactions and N–H···Br hydrogen bonds. Intriguingly, in comparison with the prototypical compound (n-propylaminium)2(formamidinium)­Pb2Br7, a remarkable augmentation of 85.2 K in the resulting T c value of BFPB is clearly observed, which further broadens the temperature range of its application. In combination with the remarkable ferroelectric and semiconducting attributes, the reversible bulk photovoltaic effect was realized in single crystals of BFPB. This finding can not only enhance the hybrid perovskite ferroelectric family but also further promote the photoelectric application of ferroelectrics.

Multi-functional hybrid perovskites with triple-channel switches and optical properties

“…The introduction of halogen atoms into organic cations can also increase the potential energy for cationic dynamic motions, which is an effective method to enhance the transition temperature of switching materials. 42–45 However, achieving one with a multi-channel response feature, suitable transition temperature, outstanding SHG signal, and excellent luminescence is still a challenge. 18,46–48…”

Tuning Dielectric Transitions in Two-Dimensional Organic–Inorganic Hybrid Lead Halide Perovskites

“…Intriguingly, 2D-layered OIHP structures integrate flexible organic components and functional inorganic frameworks, often demonstrating multiple physical properties. The organic cation acting as a stimuli-responsive cell presents temperature-dependent motional-frozen behavior, resulting in the occurrence of a phase transition coupled with other functional features in looking for well-applicative prospects to excellent capacitors, sensors, smart switches, and memory devices. − Generally, the local motions of the organic cation are accompanied by changes of the dipole moment. As a result, dielectric response is one of the most significant electrical properties among phase-transition materials, in which the bistable switching of a dielectric constant between high and low states has shown great potential in digital processing, smart devices, etc. − Very recently, some layered OIHPs have been discovered that they are suitable for exploring dielectric phase-transition materials. ,− For instance, layered lead halide perovskites were reported to exhibit evident dielectric transitions induced by a temperature-stimulated order–disorder transition of the organic component. − Moreover, layered OIHPs in cadmium/manganese halide perovskites have also been investigated to show dielectric switching due to the reversible phase transition of organic cations. , However, research on a crystal engineering strategy for tuning dielectric transitions related to the lead halide layered OIHPs is still rare .…”

Design of above-room-temperature ferroelectric two-dimensional layered halide perovskites

“…The bromide substitution in the propylammonium cation form (bromopropylammonium) 2 PbBr 4 (BPA 2 PbBr 4 , H-8), 132 and its bilayered analogue with the mixture of fomamidinium and bromopropyl ammonium cation (H-9), led to a non-centrosymmetric ferroelectric material. 133 Considering the lower electronegativity of chloride and bromide compared to fluoride, in a given organic linker and crystal structure, the latter substitution can lead to higher net spontaneous polarization.…”