Coupling Narrow Band Gap and Switchable SHG Responses in a New Molecule Ferroelectric: Imidazolyl Propylamine Pentabromo Stibium(III)

Abstract

Due to the existence of some cross properties such as SHG (second-harmonic generation), ferroelectricity, piezoelectricity, and thermoelectricity, molecular ferroelectrics have been widely used as a composite multipurpose material. Particularly, organic–inorganic molecular ferroelectrics have received much interest recently because of their unique flexible structures, friendly environment, ease of synthesis, etc. Also, these hybrids show great flexibility in band-gap engineering. Here we report a new molecular halide, [C6H13N3SbBr5] n (1; C6H13N3 = 1-(3-aminopropyl)­imidazole), which experiences a unique ferroelectric to paraelectric phase transition at around 230 K from space group P21 to P21/c. Significantly, compound 1 exhibits a narrow band gap with a value of 2.52 eV, large pronounced SHG-active, perfect rectangle hysteresis loops with a large spontaneous polarization of 6.86 μC/cm2. DSC (differential scanning calorimetry) and dielectric dependence on temperature tests and the volume change before and after the phase transition show that compound 1 is characterized by a second-order phase transition. These findings will contribute to the multifunctional materials field of organic–inorganic hybrids.

Unusual high-temperature host–guest inclusion compound-based ferroelectrics with nonlinear optical switching and large spontaneous polarization behaviours

“…In order to prove the ferroelectricity of compounds 1 and 2 at RTP , we used the Sawyer–Tower circuit method to test hysteresis loops at different temperatures. 23 As shown in Fig. 7d and e, the rectangular hysteresis loops at 300 K are well-presented, providing evidence for the room temperature ferroelectricity of compounds 1 and 2 .…”

High‐Temperature and Large‐Polarization Ferroelectric with Second Harmonic Generation Response in a Novel Crown Ether Clathrate

“…In particular, PDOS diagrams (Figure 7c) show that the valence band maximum of [(C 6 H 5 NF 3 )(18‐crown‐6)][BF 4 ] is dominated by O‐2p and H‐1s orbitals, while the C‐2p orbital contributes to conduction band minimum. Obviously, the band gap value of 1 is smaller than some organic‐inorganic hybrid perovskite semiconducting materials, such as [(C 6 H 15 ClNO) 2 CdBr 4 ] ( E g =4.75 eV), [3] [C 3 H 5 NH 3 ] 2 [CdCl 4 ] ( E g ≅5.20 eV), [12] [TMIM] 2 SnCl 6 ( E g ≅4.83 eV), [13] and larger than [C 6 H 13 N 3 SbBr 5 ] n ( E g ≅2.52 eV), [14] indicating that 1 is a good semiconductor material. Moreover, we have studied optoelectronic properties of 1 under light illumination using the 377 nm laser.…”

A multifunctional molecular ferroelectric with chiral features, a high Curie temperature, large spontaneous polarization and photoluminescence: (C9H14N)2CdBr4

“…Polarization hysteresis loop (P-E) test is the main evidence to prove whether it has ferroelectricity. 44 The P-E hysteresis loop with ideal shape is obtained by using the Sawyer-Tower circuit method, which shows that it is a ferroelectric material. As shown in Fig.…”