Photoluminescent spectroscopy measurements in nanocrystalline praseodymium doped zirconia powders

Abstract

Praseodymium doped zirconia powder (ZrO 2 : (0.53 at%) Pr 3+ ) was prepared by a co-precipitation technique and annealed in air at a temperature T a = 950 • C. The x-ray diffraction pattern shows a nanocrystalline structure composed of 29.6% monoclinic and 70.4% cubic-tetragonal phases. Medium infrared and Raman analysis confirms the monoclinic/cubic-tetragonal crystalline structure and proves the absence of praseodymium aggregates in the material. Photoluminescent spectroscopy over excitations of 457.9 and 514.9 nm (at 20 K), shows two emission spectra composed of many narrow peaks in the visible-near infrared region (VIS-NIR) of the electromagnetic spectrum, associated with 4f inter-level electronic transitions in praseodymium ions incorporated in the zirconia. Excitation and emission spectra show the different mechanisms of the direct and non-direct excitation of the dopant ion (Pr 3+ ), and the preferential relaxation of the material by charge transfer from the host (zirconia) to the 4f5d band and the 4f inter-level of the dopant ion (Pr 3+ ). No evidence of energy transfer from the host to the dopant was observed.

Structural characterization and photoluminescence behavior of pure and doped potassium strontium niobates ceramics with tetragonal tungsten–bronze structure

“…For the KSN-Pr, there are four PL bands related to 4f5d-4f 2 transitions of praseodymium (Pr 3 þ ). In this case, they are centered at around 499 nm (green), 616 nm (orange), 702 nm (red), and 813 nm (near-infrared), as a result of 3 P 0 -3 H 4 , 3 P 0 -3 H 6 , 3 P 0 -3 F 3 , and 1 D 2 -2 H 6 transitions, respectively [26][27][28]. PL property of neodymium (Nd 3 þ ) is ascribed to 4f 2 5d 1 -4f 3 transitions from excited to ground state.…”

Electrochemical characterization of praseodymium centers in Pr x Zr1−x O2 zirconias using electrocatalysis and photoelectrocatalysis

“…Additionally, the absorption spectra of Pr-doped ZrO 2 samples display two sets of narrow, weak bands over the ranges 1,350-1,550 and 1,700-1,900 nm, respectively. However, other bands in the 440-610-nm range associated with 4f inter-level electronic transitions in Pr 3+ ion are not distinguished in the spectra trace of our prepared samples [12,13]. In order to assign the observed bands to the electronic transitions yielded by the Pr cation in the available structural sites in the zirconia lattices, some comment on the results previously obtained by different authors is worthwhile.…”

“…In order to assign the observed bands to the electronic transitions yielded by the Pr cation in the available structural sites in the zirconia lattices, some comment on the results previously obtained by different authors is worthwhile. Thus, Ramos-Brito et al [12,13] reported the diffuse reflectance spectra for praseodymium-doped zirconia powders as a function of the relative amount of praseodymium with respect to the zirconium in the starting precursors. The diffuse reflectance spectra of these Pr Intensity (a.u.)…”

“…Recently, some reports on Pr x Zr 1−x O 2 materials deal with the synthesis and X-ray powder diffraction (XRD) characterization of doped zirconia crystalline forms [10] and the spectral characteristics of monoclinic and tetragonal Pr x Zr 1−x O 2 [11][12][13][14]. Although it is frequently assumed that praseodymium acts as a typical trivalent rare earth element, it is possible to expect that this element can also exhibit a +4 oxidation state when stabilized in zirconia host.…”

Structural and cathodoluminiscent properties of Zr0.95Ce0.05O2 nanopowders prepared by sol–gel and template methods

“…Therefore, luminescence studies can provide important information about intrinsic and impurity defects in pure and doped ZrO 2 [17][18]. The techniques employed to study the optical properties of lanthanide ion-doped ZrO 2 materials include cathodoluminescence [12,[18][19][20], photoluminescence [13][14][15][16][21][22][23][24][25][26][27] and thermoluminescence [12,[28][29][30][31][32] spectroscopies. Light emission from rare-earth ions is mainly due to electric and magnetic dipole optical transitions within the 4f manifolds or involving configurations such as 4f nÀ 1 and 5d [17].…”