Broadband upconversion luminescence of Er³⁺/Yb³⁺ co-doped silica glass with an interlayer-doping structure fabricated...

Upconversion luminescence (UCL) in Er³⁺/Yb³⁺ co-doped glass has great value in fields of biomedicine, 3D displays, sensors, etc. However, the bandwidth of green emission is still too narrow (usually less than 50 nm) to further improve tunability. In this work, we proposed an interlayer doping method based on selective laser sintering (SLS) technology. Er³⁺ and Yb³⁺ layers were alternately sintered. Compared with co-doped glass, the energy transition pathways were increased, where two additional green emission peaks at 486 nm and 500 nm were observed. As a result, the bandwidth was broadened from 49 to 97 nm. The noncrystalline properties, absorption peaks, and broadband mechanism in interlayer-doped samples were discussed in detail. Besides, the UCL with different Er³⁺/Yb³⁺ layer number ratios was investigated, which also confirms the feasibility of regulating red and green luminescence intensity simply through controlling the doping layer number.