Flexible Composite Energy Harvesters from Ferroelectric A₂MX₄-Type Hybrid Halogenometallates

Abstract

Two new molecular organic−inorganic hybrid halogenometallates [BnNMe 2 R]CdBr 4 (Bn = benzyl; 1: R = Me; 2: R = n-Pr) have been synthesized and found to crystallize in the acentric crystal systems suitable for ferroelectric behavior. Both these compounds exhibit well-resolved rectangular polarization vs electric field (P−E) hysteresis loops at room temperature for their polycrystalline thin films. Compounds 1 and 2 exhibited fairly high remnant polarization (P r ) values of 18.59 and 14.24 μC cm −2 , respectively. Moreover, flexible composite thin films of these halogenometallate salts with poly-(dimethylsiloxane) (PDMS) were prepared and employed as mechanical energy-harvesting devices using an impact test setup operating at a frequency of 25 Hz and an applied force of 40 N. The maximum output voltages of 52.9 and 63.8 V have been recorded for the PDMS-fabricated devices of 5 wt % of 1 and 10 wt % of 2, respectively. Also, the obtained power densities of 13.8 and 37.1 μW cm −2 for the respective 5 wt % 1−PDMS and 10 wt % 2−PDMS devices are much higher than all known devices made up of organic− inorganic hybrid materials embedded in PDMS. The energy harvested from these devices was further utilized to charge a capacitor through a full wave-bridge rectifier.

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

“…31 24 it is comparable to the phase transition temperature of TMCM-CdCl 3 (T c =400 K), 33 [BnNMe 2 R]CdBr 4 (T c = 400 K). 25 In addition, we measured TG-DTA (Fig. S6, ESI † ).…”

“…Therefore, lead free Bi-based and Cdbased hybrid metal halide are considered to be the most promising substitutes due to their low toxicity and high stability. 20 There are only a few multifunctional organicinorganic metal halide ferroelectrics containing inorganic anion CdBr 4 2-in the literature, such as (3-pyrrolinium)CdBr 3 (T c = 260 K), 21 25 Cd-based molecular ferroelectrics with both chiral and luminescent properties are rare.…”

“…Therefore, lead-free Bi-based and Cd-based hybrid metal halides are considered to be the most promising substitutes due to their low toxicity and high stability. 20 There are only a few multifunctional organic–inorganic metal halide ferroelectrics containing the inorganic anion CdBr 4 2− in the literature, such as (3-pyrrolinium)CdBr 3 ( T c = 260 K), 21 ([BrCH 2 CH 2 N(CH 3 ) 3 ] 2 + [CdBr 4 ] 2− ) ( T c = 390 K), 22 [cyclopentylammonium] 2 CdBr 4 ( T c = 340 K), 23 (diisopropylammonium) 2 [CdBr 4 ] ( T c = 244 K), 24 [BnNMe 2 R]CdBr 4 ( T c = 400 K), 25 and Cd-based molecular ferroelectrics with both chiral and luminescent properties are rare.…”

Ferroelectric Behavior of an Octahedral Metal‐Ligand Cage and Its 2D‐Connected Cage Framework

“…[2][3][4][5] Recent studies explored ferroelectrics as solar-and mechanical-energy harvesting systems. [6][7][8][9] Most commercial ferroelectrics utilize ceramic metal oxide systems. [10][11][12] However, these materials are mostly brittle, require high processing temperatures and often contain heavy and toxic elements.…”

“…Ferroelectric materials find many technological applications, such as in memory devices and sensors . Recent studies explored ferroelectrics as solar‐ and mechanical‐energy harvesting systems . Most commercial ferroelectrics utilize ceramic metal oxide systems .…”