Synergetic H-Bonding and C-T Interaction-Mediated Self-Assembled Structure Results in a Room-Temperature Ferroelectric Material Exhibiting Electric Field-Induced Dipole Switching and Piezo- and Pyroelectric Energy Conversion

Abstract

Increasing demand for flexible and wearable electronic devices has led to the development of soft ferroelectrics as a new class of piezo- and pyroelectric material. In this work, we demonstrate a supramolecular strategy for aligning dipoles through the use of two noncovalent interactions, H-bonding and charge-transfer (C-T) complexations, working synergistically toward self-assembly. In nonpolar solvents, the supramolecular scaffold (BTA-C6-NDI3) self-assembled into a columnar structure with three electron-deficient naphthalene diimide (NDI) arms around the benzene-tricarboximide core. The C-T complexation between the NDI arms and the guest molecule (pyrene) at their preorganized state results in the formation of a nanofibrous organogel network exhibiting ferroelectric (Tc ∼ 47 °C) properties at room temperature. On the basis of the remnant polarization measurement before (0.10 μC cm–2) and after the C-T complexation (0.21 μC cm–2), it has been found that the C-T complexation was critical for dipole ordering. A distinct writing response within +18 V establishes favorable dipole switching upon external voltage. The piezoelectric and pyroelectric responses observed in the organogel network suggest potential mechanical and thermal energy harvesting applications. Further, it can also be used as a self-powered biomedical sensor to monitor physiological signal monitoring.