Ferroelectricity-Tuned Upconversion Luminescence in Yb3+/Er3+-Doped Bi4Ti3O12 Thin Films for Information Photonics Applications

Ferroelectric Bi 4 Ti 3 O 12 (BIT), with a unique structure and superior ferroelectricity, can distort its lattice under an external electric field. Doping BIT with lanthanide ions (Ln 3+ ) is appealing as their luminescence intensity is sensitive to crystal symmetry changes, allowing effective modulation by an external electric field. However, current research on Ln 3+ -doped BIT primarily focuses on ceramic materials, which pose challenges for heterogeneous integration with devices. In this study, we synthesized Yb 3+ /Er 3+ -doped BIT thin films at various concentrations via the sol-gel method and systematically investigated their ferroelectric and luminescent properties. With a 0.5Yb/0.1Er doping ratio, we successfully achieved real-time, dynamic, and reversible regulation of the upconversion luminescence (UCL) intensity of BIT thin films by applying an external electric field. Furthermore, digitally encoded electrical signals were successfully converted by manipulating UCL emission into visible light intensity variation signals, and we visualized electrical logic and arithmetic operations. These findings offer new possibilities for developing information photonics applications, providing a novel approach to integrating ferroelectric and luminescent properties in thin-film materials for advanced technological applications.