Preparation and electrical properties of Sm-doped Bi2Ti2O7 thin films prepared on Pt (111) substrates

Sui, Huiting; Yang, Dongmei; Jiang, Hao; Ding, Yuhao; Yang, Changhong

doi:10.1016/j.ceramint.2012.07.035

Cited by 16 publications

(9 citation statements)

References 23 publications

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“…The wide range of the cationic radius ratio 1.46 < r (A 3+ )/ r (B 4+ ) < 1.80 (“pyrochlore field” for A 3+ 2 B 4+ 2 O 7 ), the possibility of the substitution either A- or B-site atoms, , and stability with the presence of vacancies , allow designing new pyrochlore compounds with miscellaneous properties . Bismuth titanate pyrochlore Bi 2 Ti 2 O 7 (BTO) is such an outstanding example. − New doped BTO pyrochlores may be potentially used as dielectric materials at room temperatures, − as mixed electronic-ionic conductors at intermediate temperatures for developing electrochemical devices, as luminescence compounds, − and in photocatalytic applications. − …”

Section: Introductionmentioning

confidence: 99%

Ab Initio and Experimental Insights on Structural, Electronic, Optical, and Magnetic Properties of Cr-Doped Bi₂Ti₂O₇

et al. 2019

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Combined ab initio and experimental study of Cr doping into bismuth titanate pyrochlore was carried out for the first time. Accurate firstprinciples density functional theory calculations were performed considering a Hubbard U correction (DFT+U) to account for on-site Coulomb interactions of the Cr 3d states. The possibility to synthesize a novel pyrochlore-type compound with a high dopant content Bi 1.5 Cr 0.5 Ti 2 O 7 (Bi site doping) in a fine powder state was shown via coprecipitation method, while the single-phase Bi 2 Ti 1.5 Cr 0.5 O 7 (Ti site doping) could not be obtained. Detailed descriptions of thermostability, structural, optoelectronic, and magnetic properties of Cr-doped pyrochlores in the fine (particles size 100− 300 nm) and "bulk" (1−50 μm) powder states are presented based on the well-matched results of theoretical and experimental investigations. According to the Rietveld refinement of the X-ray diffraction data, Bi 1.5 Cr 0.5 Ti 2 O 7 compound is an A-site deficient pyrochlore (Bi 1.38 Cr 0.30 )-(Ti 1.84 Cr 0.16 )O 6.44 with chromium distribution between both cationic sites. Metastability of fine powder Cr-containing pyrochlore phase was revealed during long-thermal annealing, while the bulk powder sample was stable up to its melting point 1230 °C. According to the study of electronic structure and optical properties, Cr-doped pyrochlores are wide-band semiconductors with light absorption in the range of 300−500 nm and perspective as photocatalytic active materials under visible light irradiation. Paramagnetic behavior with effective magnetic moment 3.92 μB (Bi 1.6 Cr 0.1 Ti 2 O 7−δ ) and 3.01 μB (Bi 1.5 Cr 0.5 Ti 2 O 7 ) was experimentally observed. All chromium in magnetically diluted pyrochlore Bi 1.6 Cr 0.1 Ti 2 O 7−δ exists in the form of Cr 3+ monomers, whereas in the more concentrated magnetic Bi 1.5 Cr 0.5 Ti 2 O 7 composition Cr 3+ -O-Cr 3+ dimers may also be present, with a fraction equal to 0.39. This investigation constitutes the first approach to the electronic, structural, optical, and magnetic properties of d-elements doped bismuth titanate pyrochlores from experimental and theoretical viewpoints, emphasizing the power of DFT+U to provide insights and to complement the experimental characterization of these new compounds.

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Section: Introductionmentioning

confidence: 99%

Ab Initio and Experimental Insights on Structural, Electronic, Optical, and Magnetic Properties of Cr-Doped Bi₂Ti₂O₇

et al. 2019

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“…) with pyrochlore structure has been studied as a photocatalyst that can be used to convert solar energy into H 2 and O 2 (fuels) from water [37][38][39][40][41][42][43][44][45][46][47][48]. [41], and due to the presence of active Bi 6s lone pairs, the unoccupied Bi 6p states are strongly coupled with Ti 3d antibonding states.…”

Section: Introductionmentioning

confidence: 99%

Free energy landscape approach to aid pure phase synthesis of transition metal (X=Cr, Mn and Fe) doped bismuth titanate (Bi2Ti2O7)

Mayfield

Huda

2016

Journal of Crystal Growth

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A density functional theory study of Cr, Mn and Fe substitutions in Bi 2 Ti 2 O 7 (BTO) photocatalysts is presented. We performed a stability analysis from our total energy calculations and have determined formations of dopant inspired phases are detrimental to the overall photocatalytic performance of X-doped BTO. From our calculated formation energies and electronic structures it is shown that X substitution of Ti is least stable and should be associated with formation of secondary phases more so than X substitution of Bi. This result contradicts the many experimental studies which suggest transition metal dopants always substitute Ti in BTO, but on the other hand, explains the poor photocatalytic response beyond what has become known as the critical dopant concentration.

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“…The peak marked by star around 2θ= 28.8 • in BiT thin film at 600 • C corresponds to the second phase of Bi 2 Ti 2 O 7 [18][19]. It can be seen in Fig.…”

Section: Resultsmentioning

confidence: 83%

Fabrication of Bismuth Titanate (Bi4Ti3O12) Thin Films: Effect of Annealing Temperature on their Structural and Optical Properties

Ranjbar

Behdani

et al. 2018

Scientia Iranica

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Bismuth Titanate (Bi 4 Ti 3 O 12 ) ceramics, so-called BiT, have many modern applications in microelectronics, sensors, and capacitors. In this study, the related solutions for fabricating BiT thin films were prepared and then coated on glass substrates by using the sol-gel technique and the spin coating instrument. The Xray diffraction patterns of our samples indicate that the crystalline phases of BiT are orthorhombic. Based on the transmission-spectra analysis, the samples are transparent in visible spectrum, and their optical energy gaps are found to be 3.36 eV and 3.41 eV for the BiT thin films annealed at 600 • C and 650 • C, respectively. Other physical quantities such as refractive index, thickness, extinction coefficient and dielectric constant were estimated by swanepol's method. The results show that as the annealing temperature rises the real part of the dielectric constant becomes larger indicating our samples are good dielectric materials.

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Preparation and electrical properties of Sm-doped Bi2Ti2O7 thin films prepared on Pt (111) substrates

Cited by 16 publications

References 23 publications

Ab Initio and Experimental Insights on Structural, Electronic, Optical, and Magnetic Properties of Cr-Doped Bi₂Ti₂O₇

Ab Initio and Experimental Insights on Structural, Electronic, Optical, and Magnetic Properties of Cr-Doped Bi₂Ti₂O₇

Free energy landscape approach to aid pure phase synthesis of transition metal (X=Cr, Mn and Fe) doped bismuth titanate (Bi2Ti2O7)

Fabrication of Bismuth Titanate (Bi4Ti3O12) Thin Films: Effect of Annealing Temperature on their Structural and Optical Properties

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Preparation and electrical properties of Sm-doped Bi2Ti2O7 thin films prepared on Pt (111) substrates

Cited by 16 publications

References 23 publications

Ab Initio and Experimental Insights on Structural, Electronic, Optical, and Magnetic Properties of Cr-Doped Bi2Ti2O7

Ab Initio and Experimental Insights on Structural, Electronic, Optical, and Magnetic Properties of Cr-Doped Bi2Ti2O7

Free energy landscape approach to aid pure phase synthesis of transition metal (X=Cr, Mn and Fe) doped bismuth titanate (Bi2Ti2O7)

Fabrication of Bismuth Titanate (Bi4Ti3O12) Thin Films: Effect of Annealing Temperature on their Structural and Optical Properties

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Ab Initio and Experimental Insights on Structural, Electronic, Optical, and Magnetic Properties of Cr-Doped Bi₂Ti₂O₇

Ab Initio and Experimental Insights on Structural, Electronic, Optical, and Magnetic Properties of Cr-Doped Bi₂Ti₂O₇