Macroscopic piezoelectricity of an MAPbI3 semiconductor and its associated multifunctional device

Lead halide perovskite MAPbI3 is an excellent semiconductor with an extremely long minority carrier lifetime, a long diffusion length, good light absorption, and a small bandgap of -1.55 eV. However, it is challenging to exploit the merits of its semiconductor, piezoelectric, and ferroelectric properties simultaneously. Here, an MAPbI3 single crystal is fully polarized by a series of pulsed electric fields, and its macroscopic piezoelectric and ferroelectric properties are confirmed. The piezoelectric d33 coefficient is over 7 pC/N, and the ferroelectric polarization is -2 mu C/cm2 in the tetragonal MAPbI3 crystal at room temperature. Furthermore, two interdigital electrodes are grown on the smooth surface of the MAPbI3 single crystal to prepare a multifunctional device that can sense pressure through the d31 coefficient and/or detect incident light. The detectivity of such a photodetector is as high as 7.1 x 1014 cm & sdot;Hz1/2 & sdot;W- 1 for 450-nm light. This study opens the door to developing novel multifunctional devices with single-phase piezoelectric semiconductors to realize transformations between light, force, and electrical signals.