High Piezoelectric Voltage Coefficient in Porous BaTiO 3 Single Crystals by Solid‐State Crystal Growth

ABSTRACT Porous BaTiO 3 (BTO) single crystals have been successfully fabricated via the solid‐state crystal growth (SSCG) method. The unique porous microstructure in the single crystal greatly suppresses the dielectric constant ( ε r ) and contributes to a very high piezoelectric voltage coefficient g 33 that is superior to the commercial Pb‐based piezoelectric materials. Phase‐field simulations demonstrate that stress concentration around the pores refines ferroelectric domains, and the enhanced transverse stress at domain walls contributes to polarization rotation, leading to an almost unchanged piezoelectric coefficient d 33 = 190 pC N −1 and a significantly enhanced g 33 = 52.62 × 10 −3 V m N −1 , which is confirmed by the piezo‐response force microscopy results. The electromechanical performance is systematically investigated through both theoretical analysis and experimental characterization, providing guidance for environmentally friendly device applications.