Synthesis and down conversion emission property of $\hbox {Eu}^{3+}$ doped $\hbox {LaAlO}_{3}, \hbox {CsAlO}_{2}$ and $\hbox {LiLaO}_{2}$ phosphors

Abstract

$\hbox {LaAlO}_{3}$:$\hbox {Eu}^{3+}, \hbox {CsAlO}_{2}$:$\hbox {Eu}^{3+}$ and $\hbox {LiLaO}_{2}$:$\hbox {Eu}^{3+}$ phosphors with varying concentrations of $\hbox {Eu}^{3+ }$ from 3 to 10 mol% were prepared by combustion synthesis method and the samples were further heated to 1,000 $^{\circ }$C to improve the crystallinity of the materials. The structure and morphology of materials have been examined by X-ray diffraction and scanning electron microscopy. SEM images depicted that the morphology of crystallites have no uniform shapes and sizes. Small and coagulated particles of irregular shapes of different sizes are obtained. The characteristic emissions of $\hbox {Eu}^{3+}$ were clearly observed at nearly 580, 592, 650, 682 to 709 (multiplet structure) nm for ${}^{5}\hbox {D}_{0} ~\rightarrow ~^{7}\hbox {F}_\mathrm{n}$ transitions where $\hbox {n}= 0, 1, 3, 4$ respectively, including the strongest emission peaks at 614 and 620 nm for ${}^{5}\hbox {D}_{0}~\rightarrow ~^{7}\hbox {F}_{2}$ transitions in $\hbox {CsAlO}_{2}$:$\hbox {Eu}^{3+}$ and $\hbox {LiLaO}_{2}$:$\hbox {Eu}^{3+}$ host lattices. The intensity of emission peak corresponding to ${}^{5}\hbox {D}_{0}~\rightarrow ~^{7}\hbox {F}_{1}$ transitions in $\hbox {LaAlO}_{3}$:$\hbox {Eu}^{3+}$ material is comparable to that of $^{5}\hbox {D}_{0}~\rightarrow ~^{7}\hbox {F}_{2}$ transitions which is also a singlet. Photoluminescence intensity follows the order as in $\hbox {LiLaO}_{2} > \hbox {LaAlO}_{3}> \hbox {CsAlO}_{2}$ lattices. Remarkable high photoluminescence intensity with 7 mol% doping of $\hbox {Eu}^{3+}$ in $\hbox {LiLaO}_{2}$ makes it a strong contender for red colored display applications.