Supramolecular ferroelectrics

Abstract

Supramolecular chemistry uses non-covalent interactions to coax molecules into forming ordered assemblies. The construction of ordered materials with these reversible bonds has led to dramatic innovations in organic electronics, polymer science and biomaterials. Here, we review how supramolecular strategies can advance the burgeoning field of organic ferroelectricity. Ferroelectrics - materials with a spontaneous and electrically reversible polarization - are touted for use in non-volatile computer memories, sensors and optics. Historically, this physical phenomenon has been studied in inorganic materials, although some organic examples are known and strong interest exists to extend the search for ferroelectric molecular systems. Other undiscovered applications outside this regime could also emerge. We describe the key features necessary for molecular and supramolecular dipoles in organic ferroelectrics and their incorporation into ordered systems, such as porous frameworks and liquid crystals. The goal of this Review is to motivate the development of innovative supramolecular ferroelectrics that exceed the performance and usefulness of known systems.

Chemically Driven Interfacial Coupling in Charge-Transfer Mediated Functional Superstructures

“…The ordered noncentrosymmetric crystalline structure with the generation of long-range orientation of dipoles, and the large density of CT states are beneficial for organic CT ferroelectrics. 45,46 It is consistent with the results in the inset of Figure 2j that the loading of electric field increase the alignment of the dipoles toward the crystal growth direction. The HT-C 60 crystal exhibits the optimum photoexcitation dependent polarization due to its ordered structure and relatively weak shielding effect from donating electrons to acceptors ( Figure S34a).…”

Fabrication of diisopropylammonium bromide aligned microcrystals with in-plane uniaxial polarization

“…Ferroelectricity is only possible in polar crystal structures, which account for 10 of the 32 crystallographic point groups [10], and therefore it can be challenging to engineer new ferroelectric materials with both the correct symmetry and useful properties [11]. Nevertheless, in recent years there has been an increased interest in developing organic alternatives to the inorganic ferroelectric systems [12][13][14]. Typical inorganic ferroelectrics are oxides [15,16] belonging to the ABO3 perovskite family, such as barium titanate (BTO), lead titanate and compound oxides such as lead zirconium titanate (PZT).…”

“…Molecular ferroelectrics, on the other hand, readily grow into large single crystals and afford greater synthetic flexibility than polymers, while avoiding many of the difficulties presented by oxides. For these and other reasons, there has been renewed interest in the development of new high-performance molecular ferroelectrics [12][13][14][31][32][33][34][35]. Some of the key properties of useful ferroelectrics are high spontaneous polarization, a transition temperature well above room temperature, and a low coercive field [7].…”

Control over the Self‐Assembly Modes of PtII Complexes by Alkyl Chain Variation: From Slipped to Parallel π‐Stacks

“…[5][6][7][8][9][10][11][12][13][14][15][16][17] In order to achieve these functionalities, highlyordered, adaptive nanostructures formed via a cooperative supramolecular polymerization mechanism are highly desirable. 18 The introduction of orthogonal noncovalent interactions, 19 from which hydrogen bonding and combinations with other secondary interactions are by far the most exploited ones, 20 represents a rational means for this purpose.…”