Growth, Near-Infrared luminescence Properties, and Dual-Function optical applications of Er³⁺, Yb³⁺ Co-Doped NaSrY(MoO₄)₃ single crystals

Er³⁺ ions serve as a crucial luminescent center in the 1.55 μm band, but their intrinsic absorption cross section at 980 nm is relatively small, limiting pumping efficiency. Co-doping with Yb³⁺ can act as an effective sensitizer to enhance 980 nm absorption; however, existing studies have primarily focused on powder systems, which exhibit shortcomings in thermal stability and device integration. This work successfully grew Er³⁺, Yb³⁺ co-doped NaSrY(MoO₄)₃(NSYM) single crystals using top-seeded solution growth (TSSG) method, investigating their structural, electronic, and luminescent properties. X-ray diffraction and structural refinement confirmed the successful incorporation of dopant ions. First-principles calculations revealed the modulation of electronic structure and optical bandgap. Spectroscopic studies demonstrated that Yb³⁺ doping significantly enhanced absorption at 980 nm, with a maximum absorption cross section of 9.01 × 10^-21 cm², while the excited emission cross section at 1535 nm reached 13.7 × 10^-21 cm². Employing a fluorescence intensity ratio-based temperature measurement method utilizing Er³⁺ thermally coupled energy levels, this single crystal exhibits outstanding optical temperature sensing performance, achieving a maximum relative sensitivity( S_r ) of 1.12% K⁻¹. These results indicate that Er³⁺, Yb³⁺ co-doped NSYM single crystals represent a promising integrated optical device material combining highly efficient near-infrared luminescence with high-precision self-monitoring capabilities.