2023/08/30 by Stefano Paolo Villani, Villani, Stefano Paolo, Marco Campetella +5 · 1 citation
Engineering · Materials Science · #Advanced Sensor and Energy Harvesting Materials #Conducting polymers and applications #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Perovskite Materials and Applications
paper · pdf · doi:10.48550/arxiv.2308.16070
openalex publication_date 2023/08/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Piezoelectricity of organic polymers has attracted increasing interest because of several advantages they exhibit over traditional inorganic ceramics. While most organic piezoelectrics rely on the presence of intrinsic local dipoles, a highly nonlocal electronic polarization can be foreseen in conjugated polymers, characterised by delocalized and highly responsive π-electrons. These 1D systems represent a physical realization of a Thouless pump, a mechanism of adiabatic charge transport of topological nature which results, as shown in this work, in anomalously large dynamical effective charges, inversely proportional to the band gap energy. A structural (ferroelectric) phase transition further contributes to an enhancement of the piezoelectric response reminiscent of that observed in piezoelectric perovskites close to morphotropic phase boundaries. First-principles Density Functional Theory (DFT) calculations performed in two representative conjugated polymers using hybrid functionals, show that state-of-the-art organic piezoelectric are outperformed by piezoelectric conjugated polymers, mostly thanks to strongly anomalous effective charges of carbon, larger than 5e - ordinary values being of the order of 1e - and reaching the giant value of 30e for band gaps of the order of 1 eV.