Sol-gel combustion synthesis of Sm3+ substituted La(OH)3 nanopowders for orange light-emitting phosphor

The high-efficiency Sm(3+)doped La(OH)(3) nanoparticles are synthesized in developing orange-emitting phosphors. A hexagonal phase of pure and Sm(3+)doped lanthanum hydroxide nanoparticles can be obtained by urea-assisted auto-combustion after calcination at 900 degrees C for 4 h. The dopant concentration of Sm3+ ions varied as 2, 5, and 10 wt% in the host lattice. The X-ray diffraction pattern confirmed the formation of the hexagonal phase with space group P63/m (176). The phase formation of pure and Sm(3+)ion-doped La(OH)(3) nanoparticles was confirmed using Raman spectroscopy. The band gap energy is determined to be 5.6 eV. The photoluminescence spectrum under the excitation of 407 nm exhibits four emission bands centered around orange emissions 569 nm, 605 nm, 652 nm, and 711 nm corresponding to (4)G(5/2) -> H-6(J) (J = 5/2, 7/2, 9/2, 11/2) transitions-the CIE coordinate of the Sm(3+)doped La(OH)(3) samples positioned in the orange region. The lifetime of Sm(3+)ion doped La(OH)(3) is found to be 0.36 ms, 0.708 ms, and 0.185 ms for 2, 5, and 10 wt%. The results suggest that the prepared phosphors are valuable for orange emission optoelectronic devices.