Figure 4
Thermal properties. Temperature-dependent normalized emission intensities for (a) (Ca1-x Li x )(Al1-x Si1+x )N3:Eu and (b) (Ca1-x La x )(Al1+x Si1-x )N3:Eu samples (x = 0 – 0.15). These curves are fitted by I T/I 0 = [1 + D exp(−E a/kT)]−1. Photoluminescence spectra were obtained at T = 298 K to 573 K, and is shown in the right hand side. (c) Activation energies as a function of variable x for La and Li series. (Reprinted with permission from reference [19]. Copyright 2013, American Chemical Society).