DFT-based and experimental study on Sr-doped BaTiO3: Impacts on piezoelectric and ferroelectric performance

This study combines first-principles Density Functional Theory (DFT) calculations and experimental analysis to investigate the impact of Sr-doping on the structural, electronic, and piezoelectric properties of Ba 1-x Sr x TiO 3 (BST) perovskites at different Sr concentrations (x = 0, 0.125, 0.25 theoretically; x = 0, 0.1, 0.125, 0.15, 0.2, 0.25 experimentally). Theoretical results using the Wien2K package show that increasing Sr content induces a phase shift from tetragonal phase (ferroelectric) to cubic phase (paraelectric), confirmed by XRD analysis, which also reveals an increase in grain size. Key piezoelectric parameters, including remnant polarization (P r ), piezoelectric coefficient (e 33 ), and piezoelectric constant (d 33 ), theoretical predictions closely align with experimental findings. With Sr addition, Curie temperature and electromechanical coupling factor kp (%) decrease, minimizing BST's applicability for piezoelectric applications. Nonetheless, P-E hysteresis analysis highlights its potential for energy storage due to residual and saturation polarization. Electronic studies indicate that Sr doping narrows the band gap, suggesting BST’s promise for optoelectronic, solar cell, and semiconductor applications. These findings demonstrate the multifaceted potential of Sr-doped BaTiO 3 , driven by Sr's influence on its structural, piezoelectric, ferroelectric, and electronic properties.