Unveiling Piezoelectric Property of a CsPbC13 Microcrystal for Flexible Nanogenerator Design

Inorganic (cesium) metal halide perovskites have shown great potential for incorporation into flexible nanogenerators, solar cells, and wearable electronic devices. Their low-temperature solution processability, flexibility, and piezoelectric properties have uniquely placed them over century-old ceramic piezoelectric materials. Piezoelectric properties of a material are dependent on crystal orientation and could vary in their two-dimensional thin films or three-dimensional bulk microstructure. This study shed light on the intrinsic piezoelectric property of a single microcrystal
$(3\times 2.5\mu \mathrm{m}^{2})$
of cesium lead chloride
$(\text{CsPbCl}_{3})$
. Piezoelectric properties of the microcrystals were revealed using state-of-the-art piezo response force microscopy (PFM) technique. Our measured piezoelectric charge constant
$(\mathrm{d}_{33})\text{of} 19 \text{pCN}^{-1}$
is found to be analogous to their thin film form, and higher than lithium niobate
$(\text{LiNbO}_{3})$
ceramic, and piezoelectric voltage coefficients
$(\mathrm{g}_{33})\text{of} 43.3 \text{mVmN}^{-1}$
is higher than that of Pb (Zr, Ti)
$\mathrm{O}_{3}$
(PZT). The synthesized microcrystals were further dispersed in polydimethylsiloxane (PDMS) to make a flexible nanogenerator. With a force of 4.2 N, the NG with 5 wt. %
$\text{CsPbCl}_{3}$
in the PDMS produced a peak voltage of
$\sim 40\mathrm{V}$
current of
$\sim 4.1\mu \mathrm{A}$
, and power of
$\sim 111\mu \mathrm{W}$
. This result is among the best few NGs made with organic/inorganic halide perovskite materials. This work will inspire the exploration of novel piezoelectric materials to design efficient nanogenerators for harnessing ambient vibration energies, thereby realizing self-powering nano/microdevices.