Showcasing the Structure and Properties of Lanthanide‐Doped BaTiO3

Abstract Two‐dimensional (2D) ferroelectrics, especially lead‐free materials such as barium titanate, BaTiO 3 , hold significant promise for advanced electronics due to their unique nanoscale properties. Doping BaTiO 3 with lanthanides (Ln) can enable fine‐tuning of electrical and dielectric properties by substituting Ba 2 ⁺ (A‐site) or Ti⁴⁺ (B‐site) in the perovskite structure. A‐site doping enhances dielectric properties, while doping the B‐site changes the polarization and thermal stability. The site preference depends on the ionic radii and charge compensation mechanisms, which include oxygen vacancies and self‐compensation processes. This research delivers the structural and microstructural aspects of BaTiO 3 doped with members of the Ln family from La to Lu, emphasizing their superior properties compared to undoped BaTiO 3 . Notably, the Ln dopants significantly influence the ferroelectric, ferromagnetic, luminescent, and piezocatalytic properties, where the ionic radius, doping mechanisms, defect formation, and preparation methods play a role. Theoretical studies and advanced characterization data indicate that Ln dopants improve the performance of BaTiO 3 by stabilizing structural defects, affecting site occupancy, and improving insulation resistance. Understanding the defect chemistry and Ln ion distribution in Ln‐doped BaTiO 3 systems can help optimize their functional properties for next‐generation technologies and sustainable energy applications.