A novel cyan-emitting phosphor Ba2La8(SiO4)6O2:Eu2+ for full-spectrum white light-emitting diodes

Phosphors are regarded as the crucial functioning part of white light-emitting diodes (WLEDs). Silicate-based phosphors have enjoyed numerous attentions for decades due to their varied crystal structures and high chemical stability, as well as their great application potentials. In this work, a novel cyan-emitting phosphor Ba2La8(SiO4)6O2:Eu2+ is synthesized via a high-temperature solid-state method. The phase purity was first verified by X-ray diffraction (XRD) analyses, and its structure was further solved by Rietveld refinement. The photoluminescence characteristics were investigated in detail by employing diffuse reflectance spectroscopy (DRS), fluorescence spectroscopy, and other characterization methods. The results evidence that the optimal doping concentration of Eu2+ is ∼4 mol%. The fundamental band gap of Ba2La8(SiO4)6O2:4mol%Eu2+ is estimated to be approximately 2.91 eV, which provides sufficient space to accommodate activators like Eu2+. The CIE coordinates lie in the cyan region, which allows Ba2La8(SiO4)6O2:Eu2+ to efficiently fill into the missing cyan emission in conventional WLED devices. As a proof-of-concept experiment, a prototype WLED device was then assembled, which suggests that the introduction of Ba2La8(SiO4)6O2:Eu2+ could lead to an increased color rendering index from 87 to 92. These results imply that the Ba2La8(SiO4)6O2:Eu2+ phosphors show great potential in full-spectrum WLEDs application.