Figure 2

Spectral identification of Eu²⁺ luminescent sites in h-EAO.

(a), Normalized luminescence decay curves of h-EAO monitored at 650 nm and 550 nm emissions at 77 K. The excitation source is a 355 nm Nd:YAG pulsed laser. The red solid lines are the fitted profiles. The black dashed lines are the decomposed decay compositions. Inset is a zoomed-in view of the initial stage of the decays for the two emission wavelengths. (b), Plot of PL spectral distribution (A₂/A₁) over two Eu²⁺ sites (Eu₁ and Eu₂) as a function of emission wavelengths at 77 K (solid balls). The line curves are the PL emission spectra from Eu₁ and Eu₂ sites at 77 K, which are the same as the emission curves in Fig. 1b.