Integrated Reversible Thermochromism, High T_c, Dielectric Switch and Narrow Band Gap in One Multifunctional Ferroic

Abstract

Organic‐inorganic Hybrid (OIH) materials for multifunctional switchable applications have attracted enormous attention in recent years due to their excellent optoelectronic properties and good structural tunability. However, it still remains challenging to fabricate one simple OIH compound with multi‐functionals properties, such as dielectric switching, thermochromic properties, semiconductor characteristics and ferroelasticity. Under this context, we successfully synthesized [2‐(2‐fluorophenyl)ethan‐1‐ ammonium]2SnBr6 (compound 1), which has a higher phase transition temperature of 427.7 K. Additionally, it exhibits a semiconducting property with an indirect band gap of 2.36 eV. Combining ferroelastic, narrow band gap, thermochromic, and dielectric properties, compound 1 can be considered as a rarely reported multi‐functional ferroelastic material, which is expected to give inspiration for broadening the applications in the smart devices field.

Tin-based organic–inorganic metal halides with a reversible phase transition and thermochromic response

“…The Sn–Cl bond length varies from 2.4462(16) to 2.4538(18) Å, which is consistent with related reports. 19 At LTP, both cations and anions adopt an ordered state. The [SnCl 6 ] octahedra are separated by discrete organic ammonium cations (C 3 H 9 BrN + ), forming a zero-dimensional structure.…”

“…[1][2][3][4][5][6][7][8][9][10] The perfect combination of organic and inorganic components provides feasibility for the occurrence of phase transition behavior. [11][12][13] At the same time, dielectric phase transition (thermally stimulated response) materials often bring about interesting physical properties such as fluorescence, [14][15][16] thermochromism, [17][18][19][20] ferroelectricity [21][22][23] and so on. [24][25][26][27][28][29][30] Compared with high-dimensional hybrid phase transition materials with limited organic ammonium species, the structures of low-dimensional compounds are more flexible and diverse.…”

“…53 Therefore, tin-based materials have excellent optical properties. 19,54 Additionally, tin-based halides have also received attention due to their thermochromic properties. 19 In simple terms, the color of the material changes with temperature so it can be used as a temperature indicator or alarm.…”

“…19,54 Additionally, tin-based halides have also received attention due to their thermochromic properties. 19 In simple terms, the color of the material changes with temperature so it can be used as a temperature indicator or alarm. 55 To the best of our knowledge, there are few reports on the thermochromic effect of tin-based halides, limited to our report on [2-(2-fluorophenyl)ethan-1ammonium] 2 SnBr 6 , which has both thermochromic and ferroelastic properties.…”

“…55 To the best of our knowledge, there are few reports on the thermochromic effect of tin-based halides, limited to our report on [2-(2-fluorophenyl)ethan-1ammonium] 2 SnBr 6 , which has both thermochromic and ferroelastic properties. 19 Above all, to investigate the effect of inorganic frameworks on physiochemical properties of organic-inorganic halides, (BPA) 2 SnCl 6 (1) and (BPA) 2 SnBr 6 (2) are designed by halogen modulation. Both compounds exhibit a zero-dimensional inorganic framework [SnX 6 ] 2À (X = Cl, Br) with discrete organic [BPA] + cations.…”