Pressure Coupled Lanthanide Ion Doping to Enhance Optical Properties in BaTiO₃

Abstract Self‐trapped excitons (STEs) typically give broadband photoluminescence emission with a large Stokes shift, which is important for the enhancement of the optical properties of materials. Here, low‐dimensional La‐doped BaTiO₃ nanocrystals with defects are prepared using supercritical CO₂ (SC CO₂). The generation of the STEs is facilitated by doping La³⁺ ions and introducing CO₂ pressure, which effectively enhance the luminescence intensity of BaTiO₃. This discovery shows that the La ion doping concentration can modulate the photoluminescence of BaTiO₃ nanocrystals under pressure. This work deepens the understanding of the influence of rare‐earth‐doped luminescent materials under pressure and provides insight to improve the capabilities of optical devices.