Chiral Switchable Low-Dimensional Perovskite Ferroelectrics

Abstract

Low-dimensional hybrid organic−inorganic perovskites (HOIPs) possess more localized electronic states and narrower conduction and valence bands to promote self-trapping of excitons and stronger exciton emission; therefore, they are widely used as building blocks for various applications in the fields of optoelectronics, photovoltaics, light-emitting diodes, luminescence, fluorescence, and so forth. Despite the past decades of intensive study, the discovered low-dimensional chiral HOIPs are rare as of the 1D chiral HOIP single crystals reported in 2003, as well as the low-dimensional chiral HOIP ferroelectrics are particularly scarce since the first chiral two-dimensional (2D) and/or one-dimensional (1D) HOIP ferroelectrics reported. Herein, two new low-dimensional HOIPs with the same conformational formula [R-MPA] 2 CdCl 4 (R-MPA + = (R)-(−)-1methyl-3-phenylpropylamine) were successfully synthetized by means of regulating the stoichiometric proportion of R-MPA and CdCl 2 in two ways of 1:1 (1) and 2:1 (2). By combining single-crystal X-ray diffraction, circular dichroism (CD) spectroscopy, differential scanning calorimetry, temperature-dependent dielectric constant, temperature-dependent second-harmonic generation (SHG) effect, polarization-dependent SHG response, and P−E hysteresis loop, we reveal that 1 is a 1D nonchiral molecular ferroelectric and 2 is the first zero-dimensional (0D) chiral ferroelectric with distinct CD signals; meanwhile, 2 exhibits increased properties of high-T c , large dielectric constant, SHG isotropy, and ferroelectricity than that of 1. These results not only shed light on the high tunability of the low-dimensional HOIP ferroelectrics but also open up an avenue to explore multifunctional chiral ferroelectrics.

Neutral 1D Perovskite‐Type ABX3 Phase Transition Material with a Narrowband Emission and Semiconductor Property

“…Generally, the phase change behavior of the crystal is usually accompanied by a large anomaly in dielectric behaviors [15] . Dielectric behavior can be expressed by measuring the temperature‐dependent of the real part ϵ′ of the complex permittivity ϵ ( ϵ = ϵ′ – iϵ′′ , where ϵ′′ is the imaginary part of the permittivity) [16] . Figure 3 shows that with the cooling/heating process, there are distinct ‘step‐like’ dielectric anomalies near 235 K, in good agreement with DSC result.…”

Tin‐Based Chiral Perovskites with Second‐Order Nonlinear Optical Properties

“…Organic–inorganic hybrid perovskites (OHPs), along with the excellent structural flexibility, easy accessibility, low‐cost, and outstanding optoelectrical properties, have been widely explored in the fields of solar cells, [ 13–15 ] photodetectors, [ 16,17 ] light‐emitting diodes, [ 18–20 ] and field‐effect transistors, [ 21,22 ] and NLOs. [ 23,24 ] Especially, chiral OHPs represent unique photoelectric characteristics [ 25–27 ] such as ferroelectricity, [ 28–30 ] circularly polarized photoluminescence (CPL), [ 31–33 ] bulk photovoltaic effect (BPVE) [ 34 ] as well as spintronics. [ 35–37 ] More importantly, the introduction of chiral ligands will elicit the inherent structural nonsymmetry directly.…”

Spin‐Dependent Charge Transport in 1D Chiral Hybrid Lead‐Bromide Perovskite with High Stability

“…such as luminescence and detection of circularly polarized light, [5,[9][10][11][12] nonlinear optics, [13] and ferroelectricity. [14,15] In recent years, the strong spin-orbit coupling [16][17][18] of heavy elements (Pb, I) offers new application opportunities of HOIPs in spintronics. [19] Furthermore, introducing chirality into perovskites paves the way to HOIPs-based spintronics owing to the interplay of chirality and spin, which is promising to manipulate the spin degree of freedom via chiral modification.…”