Preparation and characterization of rare earth (Pr, Nd) doped ZnO nanoparticles

Pr and Nd doped ZnO nanoparticles are prepared by simple chemical route and precursors used are ZnCl₂ and NaOH. From XRD patterns, the particles size are found to be 15, 16, 17 nm for 1 wt%, 2 wt% and 3 wt% of Pr doped ZnO nanoparticles respectively and 17,18, 19 nm for 1 wt%, 2 wt% and 3 wt% of Nd doped ZnO nanoparticles respectively. Absorption studies are carried out from 200 to 800 nm. The ZnO cut off wavelength of both the Pr and Nd doped are found near 346 nm. Pr³⁺ absorption peaks are found at 446, 463 and 589 nm and these correspond to transitions from the ground state of ³H₄ to ³P₂, ³P₁ and ¹D₂ and Nd³⁺ absorption peaks are found at 520, 578, 738 and 799 nm and these correspond to transitions from the ground state of ⁴I_9/2 to ⁴G_7/2, ⁴G_5/2 + ²G_7/2, ⁴S_3/2 + ⁴F_7/2, ⁴F_5/2 + ²H_9/2. Photoluminescence studies of the sample are also made and excitation wavelength was 325 nm. Emission bands characteristic of Pr³⁺ are observed at 450, 469, 482 and 493 nm for samples, which corresponds to ³H₄->;³P₂, ¹I₆->;³H₄, ³P₁->;³H₄ and ³P₀->;³H₄ transitions, respectively. Emission bands characteristic of Nd³⁺ are observed at 450, 473, 480 and 530 nm for samples, which corresponds to ²P_3/2 ->; ⁴I_13/2, ²P_3/2->;⁴I_15/2, ²P_1/2->;⁴I_11/2 and ⁴G_7/2->;⁴I_9/2 transitions, respectively. FTIR spectra sh- - ow the Zn-O stretching at 535 cm^-1 for the Pr doped and at 544 cm^-1 for Nd doped ZnO nanoparticles. High resolution SEM images are taken and morphology of the particles was reported.