A theoretical study on the photoluminescence of SrTiO3

Gracia, Lourdes; Longo, Valeria; Varela, José Arana; Longo, E.

doi:10.1016/j.cplett.2010.05.041

Cited by 50 publications

(45 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Based on both experimental and theoretical calculations performed by our group, we have shown that PL emission in perovskite based materials originates mainly from their structural disorder in the short-range order of these clusters. 49,56,57 During the PL process the long-range order that characterizes a crystalline structure remains. However, for the initial samples a symmetry breaking process occurs at short order, involving two clusters; i.e., structural distortions associated with imperfect coordination of Zr and Ba sites.…”

Section: Resultsmentioning

confidence: 99%

“…From recent theoretical calculations, we are able to characterize the excited electronic states where the presence of atomic under-coordination related to distorted [ZrO 5 ] and [BaO 11 ] clusters is the key ingredient. 57 Conversely, to obtain a significant RL emission, many factors should be considered as the high periodic order that must be achieved to form the cubic BZO system. Consequently, an alternative technique such as XAFS has been used to characterize these samples; XAFS was performed to better understand the influence of the local order on optical properties.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

On the reversed crystal growth of BaZrO3 decaoctahedron: shape evolution and mechanism

Moreira

Andrés

Mastelaro³

et al. 2011

CrystEngComm

View full text Add to dashboard Cite

BaZrO 3 (BZO) nanoparticles were nucleated, grown and subsequently self-assembled into a 3D decaoctahedronal architecture via a microwave-assisted hydrothermal (MAH) method. X-Ray diffraction (XRD), field emission scanning microscopy (FE-SEM), X-ray absorption spectroscopy (XAFS) as well as both photoluminescence (PL) and radioluminescence (RL) emission studies have provided fundamental insight into the nature of the anisotropic crystal growth mechanism of BZO nanocrystals into their final decaoctahedral shape. The growth mechanism of the assembled nanoparticles via mesoscale transformations to form BZO decaoctahedrons occurs from the surface to the core along a reversed crystallization route. This pathway is accompanied by a large enhancement of RL emissions while the intensity of PL emissions is enhanced and worsened along the process. The analysis of the results reveals a relationship between the decaoctahedrons obtained and their optical properties.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

On the reversed crystal growth of BaZrO3 decaoctahedron: shape evolution and mechanism

Moreira

Andrés

Mastelaro³

et al. 2011

CrystEngComm

View full text Add to dashboard Cite

show abstract

“…19,20 The vacancy remaining from the electron in an otherwise ideal cluster is a "hole polaron" which has all the attributes of an electron polaron, except that it is positively charged. 84 In this way, as a consequence, there is a Coulomb attraction between the electron polaron and the hole polaron and suggests that the recombination process in the crystal takes place through the medium of density defects or intermediary energy levels, [85][86][87][88][89] as evidenced by the UV-vis measurements. Basically, the combination occurs between all pairs of excitons generated in the ZnO nanocrystals, resulting from different organization levels in the clusters, and is a bound state whose excitation energy lies below the conduction band threshold.…”

Section: 2526mentioning

confidence: 99%

Correlation between structural and electronic order–disorder effects and optical properties in ZnO nanocrystals

et al. 2014

Self Cite

View full text Add to dashboard Cite

The correlation between structural and electronic order-disorder effects in understanding the optical properties of flower-like ZnO nanocrystals synthesized by the microwave-assisted hydrothermal method at low temperatures and short times is discussed. Theoretical simulations were performed at the density functional theory level to gain a better understanding of the experimental data from X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), electron paramagnetic resonance (EPR), ultraviolet-visible diffuse reflectance (UV-vis) spectroscopy and photoluminescence (PL) measurement studies at different temperatures. The decrease in band gap values is due to the presence of intermediate states above the conduction band. These discrete levels are formed by structural and electronic disorder of tetrahedral [ZnO 4 ] clusters which enhance the electron-hole pair.

show abstract

“…[24][25][26] Using HSE hybrid functional we obtain a band gap from the difference of the highest occupied and lowest unoccupied eigenlevels of E g = 3.37 eV when the screening parameter µ = 0.30Å −1 , E g = 4.11 eV for µ = 0.20Å −1 and E g = 4.83 eV for µ = 0.10Å −1 . Thus for all subsequent hybrid functional calculations we have used µ = 0.30 and a 2 × 2 × 2 simulation cell (40 atoms).…”

Section: Methods Of Calculationmentioning

confidence: 99%

“…With an indirect band-gap of 3.25 eV, it belongs to the class of wide-band gap semiconductor and shows optical properties. [24][25][26] SrTiO 3 is oxygen deficient (often exists as SrTiO 3−x , 0 ≤ x ≤ 0.5), which makes it suitable for oxygen sensors and solid state fuel cells. 27 Given the wide spectrum of properties and technological applications, a thorough understanding of the stability and mobility of oxygen vacancies in SrTiO 3 is imperative.…”

mentioning

confidence: 99%

Method for defect stability diagram fromab initiocalculations: A case study of SrTiO3

2012

View full text Add to dashboard Cite

Point defects play a dominant role in determining the wide spectrum of electronic and physical properties of semiconducting materials that have vast technological applications. Using ab-initio simulations, a method to calculate equilibrium defect concentrations, Fermi energy and defect stability diagrams as functions of external parameters, such as temperature and pressure, is presented. Using SrTiO3 as a representative material, we report our analysis of the stability of oxygen vacancies and interstitials, in their different charge states, as a function of temperature, oxygen partial pressure and Fermi energy of the system. Further, by analyzing the defect chemistry at experimentally relevant temperatures, we find that at low oxygen partial pressure, neutral oxygen vacancies are most dominant and at intermediate and high oxygen partial pressure, doubly charged oxygen vacancies defects are dominant.

show abstract

A theoretical study on the photoluminescence of SrTiO3

Cited by 50 publications

References 50 publications

On the reversed crystal growth of BaZrO3 decaoctahedron: shape evolution and mechanism

On the reversed crystal growth of BaZrO3 decaoctahedron: shape evolution and mechanism

Correlation between structural and electronic order–disorder effects and optical properties in ZnO nanocrystals

Method for defect stability diagram fromab initiocalculations: A case study of SrTiO3

Contact Info

Product

Resources

About