Journal ArticleDOI
Wide-range tunable bandgap in Bi1−xCaxFe1−yTiyO3−δ nanoparticles via oxygen vacancy induced structural modulations at room temperature
Pavana S. V. Mocherla,Sanjeev Gautam,Keun Hwa Chae,M. S. Ramachandra Rao,Chandran Sudakar +4 more
- Vol. 2, Iss: 9, pp 095012
TLDR
In this article, the authors demonstrate that oxygen vacancies produced by aliovalent (Ca2+) doping in BiFeO3 (BCFO) and associated structural changes due to VO ordering result in systematic alteration of the bandgap (Eg) over a wide range from 1.5 eV to 2.3 eV.Abstract:
We demonstrate that oxygen vacancies (VO) produced by aliovalent (Ca2+) doping in BiFeO3 (BCFO) and associated structural changes due to VO ordering result in systematic alteration of the bandgap (Eg) over a wide range from 1.5 eV to 2.3 eV. By contrast, the change in the bandgap of a Ca2+ and Ti4+ co-doped BiFeO3 (BCFTO) system, wherein the VO formation is suppressed, is negligible. These contrastive results strongly confirm the role of oxygen vacancies in altering the bandgap of BCFO. Irrespective of doping, microstrain, which is found to be large (0.3 to 1.2%) below a critical size (dc ~ 60 nm) also produces a small, yet linear change in the bandgap (Eg from 2.0 to 2.3 eV). The cubic phase stabilizes gradually in BCFO for x > 0.1 through an orthorhombic phase (for 0.05 0.1 in BCFTO. This change in BCFO at 300 K suggests a high-pressure-like (or high-temperature-like) effect of the oxygen vacancies and dopants on the structure. Systematic variations in the relative intensities and peak positions of Fe d–d transitions in BCFO reveal the local changes in Fe–O–Fe coordination. These results along with XANES and HRTEM studies substantiate the observed structural changes.read more
Citations
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Journal ArticleDOI
Characterization and photocatalytic activity of Y-doped BiFeO3 ceramics prepared by solid-state reaction method
TL;DR: In this article, a singe phase bismuth ferrite doped by yttrium (Bi1−xYxFeO3, x = 0, 0.05, 1, 0., 0.15, 1.2 and 0.25) was synthesized by solid-state reaction followed by sintering.
Journal ArticleDOI
Strain induced magnetic anisotropy and 3d 7 ions effect in CoFe 2 O 4 nanoplatelets
TL;DR: In this article, the compressive microstrain of 0.024 and 0.016 was estimated for CoFe2O4 samples H120 and H180 respectively using Williamson-Hall plot analysis assuming uniform deformation model.
Journal ArticleDOI
Chemical pressure induced red shift in band gap and d-d transition energies in Sr doped BiFeO3
TL;DR: In this article, the optical response of multiferroic Bi1−xSrxFeO3 (0,≤,x,≤ 0.45) samples is studied in the spectral range from 1 eV to 4 eV.
Journal ArticleDOI
Maximizing Short Circuit Current Density and Open Circuit Voltage in Oxygen Vacancy-Controlled Bi1-xCaxFe1-yTiyO3-δ Thin-Film Solar Cells.
TL;DR: This work demonstrates oxygen vacancies (VO), present within the lattice and at grain boundary (GB), can explicitly be controlled to achieve high JSC and VOC simultaneously and demonstrates the efficiency ~ 0.22 % can be achieved in solid state BFO solar cells under AM 1.5 one Sun illumination.
Journal ArticleDOI
Photoconductivity induced by nanoparticle segregated grain-boundary in spark plasma sintered BiFeO3
TL;DR: In this article, photo-response of nanoparticle-segregated grain boundary (BFO-AP) and clean grain boundary(BFO -AA) samples was investigated on spark plasma sintered BiFeO3 samples with two contrasting morphologies.
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