Dual Enhancement of Photoluminescence and Ferroelectric Polarization in Pr3+/La3+-Codoped Bismuth Titanate Thin Films.

Pr³⁺/La³⁺-codoped Bi₄Ti₃O₁₂ (BPLT) ferroelectric thin films were prepared on fused silica and Pt/TiO₂/SiO₂/Si substrates by the chemical solution deposition method, and their photoluminescence and electrical properties were investigated. Different from Pr-doped ATiO₃ (A=Sr, Ca) titanate thin films showing a red emission with the highest emission peak at 612 nm, BPLT thin films exhibited a strong blue–green emission at 493 nm. This can be ascribed to their difference of host lattice between Pr-doped titanate with a simple perovskite structure and BPLT with a bismuth-layered perovskite structure and/or the difference of site symmetry of Pr ions. It was also found that the luminescent intensity was enhanced by the incorporation of La³⁺ ions into Pr³⁺-doped Bi₄Ti₃O₁₂ (BPT) thin films. Meanwhile, the introduction of La³⁺ also greatly enhanced the ferroelectric properties of the BPT thin films. The dual enhancement of photoluminescence and ferroelectric polarization can be attributed to crystallization improvement of the BPLT thin films. It is expected that BPLT thin films can find potential applications in new multifunctional photoluminescence ferroelectric thin-film devices. [ABSTRACT FROM AUTHOR]