Figure 2

(a) FT-IR spectrum of Phellodendron phosphor; (b) UV visible absorption spectrum of Phellodendron phosphor; (c) Direct band gap estimation of Phellodendron phosphor; (d) Indirect band gap estimation of Phellodendron phosphor; (e) Relative photoluminescence excitation and emission spectra of Phellodendron phosphor (filled area) and YAG:Ce (dotted curves); (f) The PL decay spectrum of Phellodendron phosphor monitored at the emission peak (orange line). The dash line shown in (f) is a fitting result according to Eq. (2).