Room-Temperature Photoferroelectrics Semiconductor Driven by the Interlayer Confinement Effect

Abstract

With the assistance of the ferroelectrochemistry theory, many multifunctional organic−inorganic hybrid perovskites (OIHPs) ferroelectrics have been designed and studied. However, research on regulating ferroelectrics through the interlayer confinement effect in two-dimensional (2D) OIHPs is still rare. Herein, we regulated the strength of interlayer confinement by changing the length of the alkyl chain on organic cations, and precisely constructed a lead bromide ferroelectric (IPA) 2 PbBr 4 (IPA + is isopropylammonium) with a high Curie temperature (T c ) of 340.5 K and a spontaneous polarization (P s ) of 3.16 μC/cm 2 through a strong interlayer confinement effect. Compared with (IPA) 2 PbBr 4 (T p = 370.5 K), (IBA) 2 PbBr 4 (IBA + is isobutylammonium, T p = 315 K) and (IAA) 2 PbBr 4 (IAA + is isoamylammonium, T p = 271 K) crystallized in the centrosymmetric space group P2 1 /c, Cmca at room temperature (RT), respectively, while also having a lower phase transition temperature (T p ). More importantly, the gradual decrease in interlayer spacing from 10.47 Å in (IAA) 2 PbBr 4 , 7.73 Å in (IBA) 2 PbBr 4 to 5.79 Å in (IPA) 2 PbBr 4 enhances the interlayer confinement effect, leading to IBA + and IAA + cations in a disordered state at RT, while the IPA + cation can be arranged in an orderly and directional manner. Due to the differences in cations configuration, the impacts on the degree of distortion of inorganic skeleton and PbBr 6 octahedra are also different, ultimately reflected in the crystal structure. In short, the directional arrangement and order−disorder phase transition of IPA + cations induce the ferroelectricity of (IPA) 2 PbBr 4 through the strong confinement effect of the inorganic skeleton. Additionally, a single crystal device based on (IPA) 2 PbBr 4 was assembled, which exhibits a lower X-ray detection limit of 102 nGy/s in the selfdriven mode. This work provides an effective strategy for designing high-temperature photoferroelectrics semiconductors.

Regulating the Stereoisomerism of Diammonium Cations to Construct Polar Dion-Jacobson Hybrid Perovskites for Self-Powered X-ray Detection

“…Especially compared to the X-ray detection performance of RP HPs at 0 V bias, the (1,3-BMACH)­PbBr 4 detector has an absolute advantage. For example, RP-type HPs (butylammonium)­PbI 4 and (isopropylammonium)­PbBr 4 only have very low sensitivity of 11 μC Gy –1 cm –2 and 51.4 μC Gy –1 cm –2 at 0 V bias, respectively. As another important parameter for the X-ray detector, the detection limit is the ability of the device to detect the lowest X-ray dose.…”

Manganese-Based Halogen Regulation Enhances Photoluminescence Efficiency Engineering

“…During the past few years, organic–inorganic hybrids have attracted significant interest and become the topic of researchers’ concerns. − The thermodynamic and kinetic properties of these hybrids are contingent on their distinct chemical constituents and molecular arrangement. Consequently, the chemical design of organic–inorganic hybrids emerged as a focal point across diverse research fields. − Additionally, organic–inorganic hybrid halides are equally appealing due to their versatility, ease of synthesis, , structural tunability, , and optoelectronic properties. , They have demonstrated excellent performance in various properties including dielectricity, ferroelectricity, piezoelectricity, photoluminescence, thermochromism, and nonlinear optics. − Despite this, optimizing and enhancing the material performance poses challenges.…”