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

Abstract

Organic−inorganic hybrid metal halide perovskites possessing unique two-dimensional (2D)-layered structures have been demonstrated with excellent molecular tunability and stability, especially the promising semiconductor properties for solar cell applications. In this work, three 2D lead halide organic− inorganic hybrid perovskites (IAA) 2 PbX 4 (IAA = isoamylammonium cation and X = Cl, Br, and I) were synthesized by employing a solution processing method and demonstrate distinct tuning solid-state phase transitions coupled with dielectric responses, as well as light absorption properties. Among the title perovskites, the phase transition temperature decreases gradually, and their band gap also indicates a narrowing trend. The results are mainly derived from slight changes in the crystal structure by halogen regulation. These findings might provide an effective crystal engineering strategy for exploring high-performance functional perovskite materials.

Photophysical and Magnetic Properties in Zero-Dimensional (H2DABCO)MX4·nH2O (M = Mn and Cu; X = Cl and Br; n = 0, 1, and 4)

“…Recently, the class of organic–inorganic hybrid (OIH) halide compounds has emerged as a bigwig in the field of energy harvesting. − OIH halides incorporate the organic cations and inorganic halide frameworks leading to exciting optoelectronic and photovoltaic properties and potential for several applications like light-emitting diodes, photodetectors, solar cells, and so on. − The organic cation and inorganic metal halide sublattices independently or synergistically play a pivotal role in displaying dielectric, ferroelectricity, piezoelectricity, magnetism, second harmonic generation, and luminescence properties. − Although much progress has been made in lead-based hybrid halide perovskites, they are detrimental owing to their toxicity . Consequently, numerous lead-free hybrid halides have been designed, yet their low stability is their primary shortcoming. − Though researchers employed a transition metal doping strategy to minimize the toxicity, there is doubt regarding its application due to the structural deformation and charge variation .…”

H/F Substitution on the Spacer Cations Leads to 1D-to-2D Increment of the Pyrrolidinium-Containing Lead Iodide Hybrid Perovskites

“…As illustrated in Figures c,d and S9b, the theoretically calculated band gaps of (DFP) 2 PbI 4 , S -, and R -FPPbI 3 are 1.86, 2.74, and 2.67 eV, respectively. The slight difference between the experimental band gaps and the simulated ones may originate from the limitation of the DFT calculation method . Furthermore, the same wave vector of the conduction band minimum (CBM) and the valence band maximum (VBM) of S -, R -FPPbI 3 , and (DFP) 2 PbI 4 reveals their direct band gap features (Figures c,d and S9b).…”

“…Lead halogen-based hybrid organic–inorganic perovskites (HOIPs) have received remarkable attention as photoelectric materials due to their decent processability, high conversion efficiency, and low cost. − The special photophysical properties induced by spatial and dielectric confinement effects endow them with high performance for a wide range of optoelectronic applications, such as field-effect transistors (FETs), light-emitting diodes (LEDs), nonlinear optics, laser, and photodetectors. − Although the 3D HOIPs, such as CH 3 NH 3 PbI 3 , show excellent photoelectric properties and offer tremendous potential for the future photovoltaic industry, the poor environmental stability and the limited organic cation candidates induced by the Goldschmidt tolerance factor seriously hinder the development of 3D HOIPs. − In contrast, the 2D HOIPs show improved stability, great structural tunability, and diversity, which are in favor of chemical tailoring and modification. − …”

Two Manganese(II)-Based Hybrid Multifunctional Phase Transition Materials with Strong Photoluminescence, High Quantum Yield, and Switchable Dielectric Properties: (C6NH16)2MnBr4 and (C7NH18)2MnBr4

“…Multifunctional materials have many commercial and industrial applications, with rich and excellent physical properties, such as superconductivity, magnetoresistance, ferroelectricity, ion conductivity, and so on. − Organic–inorganic hybrid halides as an important component of multifunctional materials have attracted much attention for their ability to effectively regulate physical properties (light, temperature, dielectric, and/or ferroelectric properties) between several relatively different states in response to external stimuli. Materials with light or temperature stimulus–response characteristics are more important among these functional materials for their great applications in digital processing, temperature sensor, and other fields. − Therefore, a great deal of research has been done on the design of these functional materials, and a large number of reports have been made on their light or temperature stimulus–response characteristics.…”