Cyclophosphazenes offer a robust and easily modifiable platform for a diverse range of functional systems that have found applications in a wide variety of areas. Herein, for the first time, it reports an organophosphazene-based supramolecular ferroelectric [(PhCH2 NH)6 P3 N3 Me]I, [PMe]I. The compound crystallizes in the polar space group Pc and its thin-film sample exhibits remnant polarization of 5 µC cm-2 . Vector piezoresponse force microscopy (PFM) measurements indicated the presence of multiaxial polarization. Subsequently, flexible composites of [PMe]I are fabricated for piezoelectric energy harvesting applications using thermoplastic polyurethane (TPU) as the matrix. The highest open-circuit voltages of 13.7 V and the maximum power density of 34.60 µW cm-2 are recorded for the poled 20 wt.% [PMe]I/TPU device. To understand the molecular origins of the high performance of [PMe]I-based mechanical energy harvesting devices, piezoelectric charge tensor values are obtained from DFT calculations of the single crystal structure. These indicate that the mechanical stress-induced distortions in the [PMe]I crystals are facilitated by the high flexibility of the layered supramolecular assembly.
Keywords: cyclophosphazene; energy harvester; ferroelectric; piezoelectric; piezoresponse force microscopy.
© 2023 The Authors. Small published by Wiley-VCH GmbH.