Poling effect on the electrostrictive and piezoelectric response in CH3NH3PbI3 single crystals

Methylammonium lead triiodide perovskites (MAPbI(3)) have demonstrated a large electrostrictive strain up to 1%, which was theoretically proved to be related to the additional defects under applied bias voltages. However, as this effect was detected only at a low frequency, we explored the electrostrictive response at a higher frequency (4kHz) by using ac poling at 1Hz. In such conditions, the electrostrictive coefficient was evaluated at -45.7nm(2) V-2, i.e., quite larger than the results under dc poling or in unpoled samples. The occurrence of a high-frequency electrostrictive effect may be correlated with the defects that rise in the ac poled samples from the ion migration under reverse bias as it was also demonstrated from the shift of the dielectric loss peak in the considered systems. In parallel to the electrostrictive effect, the piezoelectric response shows a drastic increase after the ac and dc poling due to the lattice distortion induced by the applied electric field. Based on the above approach, the achieved electrostrictive and piezoelectric responses at 4kHz in MAPbI(3) may open opportunities in the area of actuators, energy-harvesting, and micro-electromechanical systems.

Automated summary

The study found that methylammonium lead triiodide perovskites exhibit a stronger electrostrictive effect at higher frequencies, possibly related to additional defects induced by applied bias voltage. After ac and dc poling, the piezoelectric response also showed a significant increase, possibly due to lattice distortion induced by the applied electric field.