Abstract:CaZrO3 (CZO) powders were synthesized at different temperatures (400, 600, 800, and 1000 °C) and characterized by X-ray diffraction, Raman and ultraviolet-visible spectroscopic methods, along with photoluminescence (PL) emissions. First principle calculations based on the density functional theory (DFT), using a periodic cell models, provide a theoretical framework for understanding the PL spectra based on the localization and characterization of the ground and electronic excited states.Fundamental (singlet, s… Show more
“…We link the excited states theory to the generation of electron-hole pairs, providing a deeper understanding of optical effects in the solid state. This new approach was proposed in previous studies and has been confirmed in the present work 25 . The proposed connection between excited states and optical properties is well established in quantum chemical approaches; however, the present quantum evidence of dangling bonds generating electron-trapping levels and localizing spin density is entirely new.…”
Section: Figuresupporting
confidence: 85%
“…It is important to point out that in this study the Eu 3+ doping of the CZO matrix was modeled allowing lattice and atomic position relaxation for the singlet state, and calculations were carried out for both bulk and slab models, using the optimized cell for ordered and disordered models of CZO reported in our previous work 25 ; this enabled the computational treatment of the main electronic features associated with the doping process and the optical properties. well-defined peaks, denoting a high degree of crystallinity, without any secondary phases.…”
Section: Computational Detailsmentioning
confidence: 99%
“…4(a-c) properties, in this study we investigated excited singlet (s*) and triplet (t*) states by combining the analyses mentioned above. The main purpose was to rationalize the PL emission of CZO:Eu 3+ following an approach similar to that employed in our previous study of pure CZO 25 .…”
Section: Theoretical Analysismentioning
confidence: 99%
“…From a theoretical viewpoint, the investigation of PL emissions is a challenging task because it requires a detailed understanding of the excited states involved in the optical phenomena 1, 24 . In our previous work, we presented a novel approach to explore ground (singlet) and excited (singlet and triplet) states involved in the experimental PL spectra of CZO nanoparticles 25 . This approach was successfully applied by our group to investigate the mechanism of PL emission in SrTiO3, SrTiO3:Sm, CaWO4, BaZrO3, and BaZr1-xHfxO3 solid solutions, based on the characterization of excited electronic states [26][27][28][29][30][31] .…”
In this study, we present a combined experimental and theoretical study of the geometry, electronic structure, morphology, and photoluminescence properties of CaZrO3:Eu3+ materials.
“…We link the excited states theory to the generation of electron-hole pairs, providing a deeper understanding of optical effects in the solid state. This new approach was proposed in previous studies and has been confirmed in the present work 25 . The proposed connection between excited states and optical properties is well established in quantum chemical approaches; however, the present quantum evidence of dangling bonds generating electron-trapping levels and localizing spin density is entirely new.…”
Section: Figuresupporting
confidence: 85%
“…It is important to point out that in this study the Eu 3+ doping of the CZO matrix was modeled allowing lattice and atomic position relaxation for the singlet state, and calculations were carried out for both bulk and slab models, using the optimized cell for ordered and disordered models of CZO reported in our previous work 25 ; this enabled the computational treatment of the main electronic features associated with the doping process and the optical properties. well-defined peaks, denoting a high degree of crystallinity, without any secondary phases.…”
Section: Computational Detailsmentioning
confidence: 99%
“…4(a-c) properties, in this study we investigated excited singlet (s*) and triplet (t*) states by combining the analyses mentioned above. The main purpose was to rationalize the PL emission of CZO:Eu 3+ following an approach similar to that employed in our previous study of pure CZO 25 .…”
Section: Theoretical Analysismentioning
confidence: 99%
“…From a theoretical viewpoint, the investigation of PL emissions is a challenging task because it requires a detailed understanding of the excited states involved in the optical phenomena 1, 24 . In our previous work, we presented a novel approach to explore ground (singlet) and excited (singlet and triplet) states involved in the experimental PL spectra of CZO nanoparticles 25 . This approach was successfully applied by our group to investigate the mechanism of PL emission in SrTiO3, SrTiO3:Sm, CaWO4, BaZrO3, and BaZr1-xHfxO3 solid solutions, based on the characterization of excited electronic states [26][27][28][29][30][31] .…”
In this study, we present a combined experimental and theoretical study of the geometry, electronic structure, morphology, and photoluminescence properties of CaZrO3:Eu3+ materials.
“…The Wulff proposal refers to a simple relation between E surf and the distance in the normal direc tion from the center of the crystallite, which also allows this ideal morphology to be modified by tuning the surface energies of the different facets [62,63]. In recent years, this method was successfully applied for different kinds of materials, showing excellent agreement between theoretical predicted and experimental reported morphologies [45,[64][65][66][67].…”
Section: Superficial Magnetism and Crystal Morphologymentioning
The present study illustrates how density functional theory calculations can rationalize the surface structure and magnetism for the low-index (1 1 0), (1 0 1), (1 0 0), (0 0 1), (1 1 1), and (0 1 2) surfaces of MnTiO 3. A simple procedure, without surface reconstructions or chemical adsorptions in which the stability, magnetism and the morphological transformations is presented in detail to clarify the control of their multiferroic nature. The surface stability was found to be controlled by the octahedral [MnO 6 ] and [TiO 6 ] clusters formed by the Mn 2+ and Ti 4+ cations-i.e., their local coordination at the surfaces, respectively-with nonpolar (1 1 0) being the most stable. Enhanced superficial magnetism was found for (0 1 2), (0 0 1), and (1 1 1) surfaces in agreement with the more undercoordinated [TiO n ]′ and [MnO n ] • complex clusters at the surface plane. Our calculation suggests the existence of magnetic [TiO n ]′ species for unstable (0 0 1) and (1 1 1) surfaces, explained by the unusual crystal-field associated with the surface environment. The crystal morphology has been predicted to determine the most likely terminations to be present as well as the intrinsic magnetization density associated with morphologies. Moreover, the (0 0 1) surface plane plays a key role in the enhancement of the magnetic properties for shape-oriented MnTiO 3 nanoparticles, suggesting a superior magnetoelectric coupling due to the presence of uncompensated spins and polar distortions perpendicular to the surface plane.
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