Fabrication and characterization of high-performance Bi3+-doped Y2O3 transparent ceramics for cyan-emitting LEDs

Cyan-emitting LEDs are critical for advanced solid-state lighting, yet conventional phosphor-converted devices face thermal and encapsulant issues. All-solid-state transparent ceramics are promising alternatives, but cyan-emitting ones remain largely unexplored. Herein, novel cyan-emitting Bi 3+ :Y 2 O 3 transparent ceramics were prepared via vacuum sintering. The samples exhibit a dense microstructure, high visible transmittance, strong UVC/UVB shielding, and excellent mechanical properties. Bi 3+ occupies C 2 and S 6 lattice sites, producing dominant cyan (495 nm, C 2 ) and weak violet (423 nm, S 6 ) emissions under 332 nm excitation. The two emissions show distinct thermal responses due to thermally activated energy transfer from C 2 to S 6 , and the sample retains 75% of its intensity at 373 K with stable cyan color. The ceramic-based LED exhibits bright cyan emission, eliminating the aging issues of phosphor-converted devices. This work demonstrates the potential of Bi 3+ : Y 2 O 3 transparent ceramics for cyan-emitting LEDs in low-light and medical applications, as well as UV-shielding windows.