Synthesis and piezoelectric response of cubic and spherical LiNbO ₃ nanocrystals

Methods have been developed for the shape-selective synthesis of ferroelectric LiNbO ₃ nanoparticles. Decomposition of the single-source precursor, LiNb(O-Et) ₆, in the absence of surfactants, can reproducibly lead to either cube- or sphere-like nanoparticles. X-Ray diffraction shows that the LiNbO ₃ nanoparticles are rhombohedral (R3c). Sample properties were examined by piezoresponse force microscopy (PFM) and Raman where both sets of nanoparticles exhibit ferroelectricity. The longitudinal piezoelectric coefficients, d ₃₃, varied with shape where the largest value was exhibited in the nanocubes (17 pm V ^-1 for the cubes versus 12 pm V ^-1 for spheres).