Broadband yellow-green emitting Bi3+-doped La2MgHfO6 double perovskite phosphor for WLED

Broadband yellow-green-emitting materials help to improve the color rendition performance of phosphor-converted white light-emitting diodes (pc-WLEDs). Herein, we report a Bi 3+ -activated double perovskite (La 2 MgHfO 6 ) broadband yellow-green-emitting phosphor synthesized via high-temperature solid-state reaction. Structural characterization confirms phase-pure crystallization in the P21/n space group, while spectral analysis reveals a broad yellow-green emission (λ em  = 544 nm, FWHM = 137 nm) under 370 nm excitation, attributed to the parity-allowed 3 P 1 → 1 S 0 transition of Bi 3+ in [LaO 8 ] dodecahedron and [Mg/HfO 6 ] octahedra. The material effectively suppresses concentration quenching owing to the relatively large interionic distances within its crystal structure. Meanwhile, its emission peak exhibits a red-shifting (Δλ = 30 nm) with varying excitation wavelengths, which stems from the distinct responses of different luminescent centers to excitation energy. Additionally, it demonstrates good thermal stability, with minimal temperature-induced changes in peak position and full width at half maximum (FWHM). When combined with commercial red (CaAlSiN 3 :Eu 2+ ) and blue (BAM:Eu 2+ ) phosphors, the fabricated WLED exhibits bright white light with superior color rendering (Ra = 86.9) and comfortable correlated color temperature (CCT = 4994 K). The yellow-green emission significantly enhances spectral continuity, demonstrating great potential as a rare-earth-free component for high-quality full-spectrum lighting systems.