Enhanced Nanoscale Piezoresponse and Ferroelectricity in Polymer Nanofiber Through Interfacial Interaction Controlled Molecular Dipole Orientation Using Perovskite Dopant

Amidst the worldwide growing energy demand, mechanical to electrical energy conversion through piezo- and ferroelectric effect can be a feasible solution. In this quest, piezoelectric polymer poly(vinylidene fluoride-hexafluoroproylene) (P(VDF-HFP)) has gained interest due to good mechano-sensitivity, flexibility and easy fabrication.¹ Noteworthy that P(VDF-HFP) has different crystalline polymorphs including non-electroactive phase, α and electroactive β and γ.^2,3 Here, inorganic halide perovskite (IHP) CsPbI₃ was used as a dopant to nucleate the highest electroactive ferroelectric β-phase and explicit control of molecular dipole orientation responsible for the electroactive functionality of P(VDF-HFP). CsPbI₃ aids in favourable molecular dipole orientation in electrospun P(VDF-HFP)-CsPbI₃ composite nanofiber leading to enhanced nanoscale piezoresponse and ferroelectric switching. The composite nanofiber features a higher piezoelectric d₃₃ coefficient of ∼30 pm/V and longer ferroelectric polarization retention. It was used for mechanical energy harvesting and achieved highest power density of ∼2 mW/m². The nanofiber can monitor several human physiological motions which could be utilized in humanoid and surgical robotics in healthcare.



References:

1. J. Appl. Phys. 2016, 120, 174501.

2. Science 1983, 220, 1115-1121.

3. Nano Energy 2022, 100, 107451.