Static and dynamic strain-driven photoluminescence tuning in rare-earth doped perovskite oxide thin films

Recently, there have been significant interest in the wide potential of photoluminescence (PL) response of rare-earth doped perovskite oxide thin films in the field of optoelectronics. This work reports an effective method to modulate the PL properties of 0.8 mol%Sm³⁺-doped BaTiO₃ (BTO:Sm) thin films through static and dynamic strain. BTO:Sm films were epitaxially grown on LaAlO₃ (LAO), 0.7Pb(Mg_1/3Nb_2/3)O₃-0.3PbTiO₃ (PMN-PT), MgO, and Mica single-crystal substrates by pulsed laser deposition technique. Compared with the BTO:Sm/PMN-PT heterostructure which experiences minimal lattice mismatch effect, the PL intensity of BTO:Sm/LAO and BTO:Sm/MgO is enhanced by 818.1% and 1014.7%, respectively, due to static tensile/compressive strain (-0.429% and 0.461%) during the epitaxial growth process. In the flexible BTO:Sm/Mica heterostructure, dynamic strain is introduced through mechanical bending. Compared with the unbent state, the u-type and n-type bending modes increase the relative changes in PL intensity (ΔI/I) by 599.0% and 768.5%, respectively. Particularly, BTO:Sm/Mica also exhibits a remarkable optical transmittance exceeding 75% (500–2500 nm). The enhancement of PL intensity is closely related to the adjustment of lattice strain, which changes the crystal field strength of the BTO:Sm and the radiative transition probability. This work provides valuable insights for designing future optoelectronic devices and environmental monitoring equipment. It has the potential to advance photonics and sensor technologies, paving the way for innovation and exploration in these fields.