Towards an insight on the photoluminescence of disordered CaWO4 from a joint experimental and theoretical analysis

Orhan, Emmanuelle; Anicete-Santos, M.; Maurera, M. A. M. A.; Pontes, F. M.; Souza, A. G.; Andrés, Juán; Beltrán, Armando; Varela, José Arana; Pizani, P. S.; Taft, Carlton A.; Longo, Elson

doi:10.1016/j.jssc.2004.12.038

Cited by 54 publications

(42 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4). However, a strong band of the excitonic origin is shifted to smaller energies below ∼ 4 0 eV, due to a decrease of the optical band gap caused by disorder [28]. The presence of local structural relaxation in nano-ZnWO 4 is confirmed by the extended x-ray absorption fine structure (EXAFS) studies 2 and is in agreement with the recent Raman and luminescence results [19].…”

Section: Resultssupporting

confidence: 89%

Electronic excitations in ZnWO4 and ZnxNi1−x WO4 (x = 0.1 − 0.9) using VUV synchrotron radiation

et al. 2011

View full text Add to dashboard Cite

Abstract:The photoluminescence spectra and luminescence excitation spectra of pure microcrystalline and nano-sized ZnWO 4 as well as the Zn Ni 1− WO 4 solid solutions were studied using vacuum ultraviolet (VUV) synchrotron radiation. The samples were also characterized by x-ray powder diffraction. We found that: (i) the shape of the photoluminescence band at 2.5 eV, being due to radiative electron transitions within the [WO 6 ] 6− anions, becomes modulated by the optical absorption of Ni 2+ ions in the Zn Ni 1− WO 4 solid solutions; and (ii) no significant change in the excitation spectra of Zn 0 9 Ni 0 1 WO 4 is observed compared to pure ZnWO 4 . At the same time, a shift of the excitonic bands to smaller energies and a set of peaks, attributed to the one-electron transitions from the top of the valence band to quasi-localized states, were observed in the excitation spectrum of nano-sized ZnWO 4 .PACS (2008)

show abstract

Section: Resultssupporting

confidence: 89%

Electronic excitations in ZnWO4 and ZnxNi1−x WO4 (x = 0.1 − 0.9) using VUV synchrotron radiation

et al. 2011

View full text Add to dashboard Cite

show abstract

“…This emission was quite different from previous results of crystalline CaWO 4 powders synthesized by the polymeric precursor method were the PL emission has a maximum centered at 520 nm, the green area of visible spectra. 69,104 Both CaWO 4 crystals, obtained by processing in MH system and polymeric precursor method, were crystalline at long range order in agreement with XRD analyses. However, the difference in the maximum PL emission between the samples obtained by the two methods show that there are structural differences between them.…”

Section: -7supporting

confidence: 71%

“…104 The exponential optical absorption edge and the optical bandgap energy are controlled by the degree of structural disorder in the lattice. The decrease in the bandgap can be attributed to defects, local bond distortion, intrinsic surfaces states and interfaces which yield localized electronic levels in the forbidden bandgap.…”

Section: E Uv-vis Measurements Analysismentioning

confidence: 99%

Presence of excited electronic state in CaWO4 crystals provoked by a tetrahedral distortion: An experimental and theoretical investigation

Gracia

Longo

Cavalcante

et al. 2011

Journal of Applied Physics

Self Cite

View full text Add to dashboard Cite

By combining experimental techniques such as x-ray diffraction, Fourier transform Raman, ultraviolet-visible, x-ray absorption near edge structure, extended x-ray absorption fine structure spectroscopy, and theoretical models, a general approach to understand the relationship among photoluminescence (PL) emissions and excited electronic states in CaWO 4 crystals is presented. First-principles calculations of model systems point out that the presence of stable electronic excited states (singlet) allow us to propose one specific way in which PL behavior can be achieved. In light of this result, we reexamine prior experiments on PL emissions of CaWO 4 .

show abstract

“…We are focusing on the effect of periodic local structural deformation among the numerous possible irregularities. This strategy of models with the coexistence of different types of environments around the network former has already been successfully employed in studying the PL emission in orderdisordered structures of scheelite tungstates [51][52][53] and of perovskite titanates. [54][55][56][57][58][59] In the case of the perovskite titanates, the cationic environments had fivefold MO 5 ͑M =Ti,Zr͒ and sixfold MO 6 coordinations.…”

Section: Crystal Structure and Periodic Modelsmentioning

confidence: 99%

Contribution of structural order-disorder to the green photoluminescence ofPbWO4

et al. 2007

View full text Add to dashboard Cite

An intense and broad visible photoluminescence ͑PL͒ band was observed at room temperature in structurally disordered PbWO 4 thin films. The scheelite lead tungstate ͑PbWO 4 ͒ films prepared by the polymeric precursor method and annealed at different temperatures were structurally characterized by means of x-ray diffraction and atomic force microscopy analysis. Quantum-mechanical calculations showed that the local disorder of the network modifier ͑Pb͒ has a very important role in the charge transfer involved in the green PL emission. The experimental and theoretical results are in good agreement, both indicating that the generation of the intense visible PL band is related to simultaneous structural order and disorder in the scheelite PbWO 4 lattice.

show abstract

Towards an insight on the photoluminescence of disordered CaWO4 from a joint experimental and theoretical analysis

Cited by 54 publications

References 38 publications

Electronic excitations in ZnWO4 and ZnxNi1−x WO4 (x = 0.1 − 0.9) using VUV synchrotron radiation

Electronic excitations in ZnWO4 and ZnxNi1−x WO4 (x = 0.1 − 0.9) using VUV synchrotron radiation

Presence of excited electronic state in CaWO4 crystals provoked by a tetrahedral distortion: An experimental and theoretical investigation

Contribution of structural order-disorder to the green photoluminescence ofPbWO4

Contact Info

Product

Resources

About