Morphotropic Phase Boundary in Polarized Organic Piezoelectric Materials

Designing the morphotropic phase boundary (MPB) has been the most sought-after approach to achieve high piezoelectric performance of piezoelectric materials. However, MPB has not yet been found in the polarized organic piezoelectric materials. Here, we discover MPB with biphasic competition of β and 3/1-helical phases in the polarized piezoelectric polymer alloys (PVTC-PVT) and demonstrate a mechanism to induce MPB using the compositionally tailored intermolecular interaction. Consequently, PVTC-PVT exhibits a giant quasistatic piezoelectric coefficient of >32 pC/N while maintaining a low Young's modulus of 182 MPa, with a record-high figure of merit of piezoelectricity modulus of about 176 pC/(N·GPa) among all piezoelectric materials.