Discrete Molecular Copper(II) Complex for Efficient Piezoelectric Energy Harvesting Above Room‐Temperature

Abstract

Developing robust, wearable, and biocompatible energy harvesting devices with bulk oxides (ceramics and perovskites) is extremely hard to achieve due to their zero mechanical flexibility, heavy metal toxicity, and tunability of properties. Alternatively, discrete inorganic complexes can be an excellent choice to overcome the above‐stated issues, thanks to appropriate molecular engineering. Herein, we report an above‐room‐temperature ferroelectric discrete molecular complex [Cu(L‐phe)(bpy)(H2O)]PF6⋅H2O (1) which is suitable for piezoelectric energy harvesting due to its large values of piezoelectric co‐efficient (d33=10 pm V−1) and spontaneous polarization (Ps=1.3 μC cm−2). Among the devices prepared with the composite films of polyvinyl alcohol (PVA) and various weight % composition of 1, the 10 Wt % composite shows the highest output voltage of 8 V, a power density of 0.85 μW cm−2, and output current of 5 μA, which is highest for any discrete inorganic complex reported to date.

Nanoconfinement Effect in Water Processable Discrete Molecular Complex-Based Hybrid Piezo- and Thermo-Electric Nanogenerator

“…Figure a shows the atomic force microscopy (AFM) topography image of PVPF 6 fiber and the corresponding phase image (Figure b) indicates the localized orientation of ferroelectric nanoconfined domains of 1 . The observed Curie transition in PVPF 6 nanofibers confirms the ferroelectric nature of 1 at room temperature (Figure c), which is consistent with the transition observed in pure 1 . The obtained PE loop and polarization switching induced strain in PVPF 6 fibers indicates the ferroelectric and piezoelectric nature, respectively (Figure d).…”

“…The observed Curie transition in PVPF 6 nanofibers confirms the ferroelectric nature of 1 at room temperature (Figure 2c), which is consistent with the transition observed in pure 1. 24 The obtained PE loop and polarization switching induced strain in PVPF 6 fibers indicates the ferroelectric and piezoelectric nature, respectively (Figure 2d). Thereafter the advantage of the enhanced piezoelectricity of nanoconfined fibers is shown by improved performance of piezoelectric nanogenerator (PENG) as compared to nanocomposite film (Figure 2e).…”

Deciphering the anisotropic energy harvesting responses of an above room temperature molecular ferroelectric copper(ii) complex single crystal

“…This electrical output is one of the largest outputs among the discrete molecular PENG devices reported in the literature and is comparable to those of certain conventional bulk oxide devices. 3,11,12 We also report the pyroelectric energy harvesting of the single crystal of 1 (along the b -axis) with a pyroelectric coefficient of 29 μC m −2 K. To the best of our knowledge, this is the first report on single-crystal anisotropic mechanical and thermal energy harvesting based on a discrete molecular complex.…”

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

“…The origin of the enhanced remnant polarization is attributed to the hierarchical assembly of donor and acceptor entities, around the polar BTA-core. Notably, the hysteresis loops appear to exhibit a slightly lossy behavior owing to the presence of semiconducting properties. , The frequency dependence of the P – E loop is shown in Figure S15, Supporting Information. Hereafter, we proceed further with our studies primarily with the C-T complex due to its superior ferroelectric properties.…”