Yb3+-Mediated Luminescence Enhancement in Er3+-Doped 3D-Printed ZrO2 Microarchitectures

• Photoluminescence and cathodoluminescence reveal dopant effects on emission properties. • Yb 3+ enhances Er 3+ emissions in 3D ZrO 2 architectures. • Thermal treatments stabilize t-ZrO 2 and induce m-ZrO 2 phase transitions. • Optical characterization reveals reduced defect emissions in thermally treated architectures. Lanthanide-doped ZrO 2 ceramics are promising materials for optics due to their high refractive index and tunable luminescent properties. In this study, we investigated the impact of Yb 3+ and Er 3+ dopant concentrations on the emission behavior of lanthanide-doped 3D ZrO 2 microarchitectures fabricated using two-photon lithography. Thermal treatments have been carried out at 600°C and 750°C to promote the stabilization of the ZrO 2 tetragonal phase ( t -ZrO 2 ) and at 1000°C to induce phase transition in ZrO 2 to the monoclinic ( m -ZrO 2 ) phase in the 3D microarchitectures. Scanning transmission electron microscopy confirmed the crystallinity changes across the thermal treatments. Photoluminescence (PL) and cathodoluminescence (CL) measurements confirm emission bands of Yb 3+ and Er 3+ single dopants and Yb 3+ :Er 3+ co-dopants. Variations in Yb 3+ content reveal that the PL emission of Er 3+ increases (e.g., 4 S 3/2 → 4 I 15/2 ), which is attributed to the interplay between the dopant concentrations, defect structures and the ZrO 2 host. The results highlight the importance of ZrO 2 microarchitectures' crystallinity and co-doping relationship, which enable the promotion of Er 3+ emissions. We expect our research will find applications in 3D optical systems.