Organic piezoelectric materials: milestones and potential

Abstract

Research on the piezoelectric response of biomolecules has intensified following demonstration of open circuit voltages of over 20 V in biopiezoelectric generators. Organic piezoelectric nanotubes, fibers, and micro-islands have been grown and studied; however, the lack of fundamental understanding of the piezoelectric effect in nature hinders the rational design of biomaterials to provide a tailor-made piezoelectric response. Advances in high performance computing have facilitated the use of quantum mechanical calculations to predict the full piezoelectric tensor of biomolecular crystals, including amino acids and small peptides. By identifying directions of high piezoelectric response, the simulations can guide experimental crystal growth, device fabrication and electrical testing, which have led to the demonstration of unprecedented piezoelectric responses in organic crystals on the order of 200 pC/N. These large responses arise from strong supramolecular dipoles, which can be tuned by molecular chemistry and packing, opening new opportunities for the realization of technologically useful piezoelectric devices from renewable materials. The amino acids predicted to exhibit the highest piezoelectric response, such as glycine, hydroxyproline and lysine, are anticipated to be used to engineer highly piezoelectric peptides in the future. With improved scaling of advanced computational methods, such as density functional perturbation theory, the research community can begin to efficiently screen peptide structures for enhanced electromechanical properties. This capability will accelerate the experimental development of devices and provide much-needed insight into the evolution of a hierarchical relation in biological materials starting from strongly piezoelectric building blocks.

Half a century of amyloids: past, present and future

“…Other studies indicated the materials-like properties of amino acid assemblies and the piezoelectric properties of amino acid crystals. 353 The overall organization of the metabolites in those systems seems to be related to metabolite amyloids, highlighting once again the similarity between the protein and non-proteinaceous selfassembling systems.…”

Recent Advances in Organic Piezoelectric Biomaterials for Energy and Biomedical Applications

“…Glycine (G) is a zwitterionic amino acid and a good model building block for investigating the process of polymorphic crystallization [34][35][36]. At ambient conditions, the crystalline glycines have three distinct structures, α-, β-, and γ-structures, where the βand γ-structures have shear piezoelectricity due to their acentric structures [37][38][39][40]. Herein, the piezoelectricity arises from the displacement of ion in the crystal, as it does in the inorganic materials, and such displacement creates a dipole in local, and a net polarization in bulk, material, as shown in Figure 1c.…”

Influence of the Stabilization Process on the Piezotronic Performance of Electrospun Silk Fibroin

“…Energy harvesting from environmental mechanical vibration sources is a promising technology where reliable power sources are unavailable, [ 1,2 ] and it can increase the lifetime of a system while reducing device maintenance.…”

“…There is an increasing interest in new energy harvesters to power wearable personal electronic devices without the need for external power sources like batteries. [ 3 ] These devices find potential applications to monitor human gait, [ 2,4,5 ] personalized healthcare, [ 6 ] sports training, [ 7 ] and thus allowing a continuous assessment of health conditions, and are a powerful tool in the development of accurate treatment plans. [ 8 ]…”

“…Different mechanisms can be used to build energy harvesters and wearable sensor devices, like thermoelectric, [ 9 ] triboelectric [ 4 ] and piezoelectric materials. [ 2 ] Thermoelectric materials rely on a temperature gradient from a cold to a hot side to generate energy, [ 9 ] while triboelectric devices are limited to a maximum vibration frequency of 10 Hz to be able to generate an electrical signal output, they present low durability due to wear and tear at the surfaces of the electrical contacts, and are sensitive to environmental humidity, especially during packing. [ 10 ]…”