Tailoring the structural, optical properties and photocatalytic behavior of ferroelectric Bi 0.5 K 0.5 TiO 3 nanopowders

Bac, Luong Huu; Thanh, Le Thi Hai; Chính, Nguyễn Văn; Khoa, Nguyen Tri; Thiet, Duong Van; Trung, Trinh Van; Dũng, Đặng Đức

doi:10.1016/j.matlet.2015.11.086

Cited by 42 publications

(11 citation statements)

References 20 publications

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“…Figure 3(a) presents the optical absorbance spectra of undoped Bi 0.5 Na 0.5 TiO 3 and CaFeO 3-δ -modified Bi 0.5 Na 0.5 TiO 3 materials at various concentrations at room temperature. The pure Bi 0.5 Na 0.5 TiO 3 samples exhibited a single absorbance edge, which is consistent with the recently reported optical properties of Bi 0.5 Na 0.5 TiO 3 materials 29,30,50,51 . The addition of CaFeO 3-δ to Bi 0.5 Na 0.5 TiO 3 caused the absorbance edge to shift to high wavelengths, indicating that the electronic band structures had been modified.…”

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confidence: 91%

“…Lin et al reported that a self-trapped excitation possibly originated from the PL of the Bi 0.5 Na 0.5 TiO 3 materials, whereas the distortion of the TiO 6 octahedra due to surface stress resulted in a blue shift in the emission peak 58 . Bac et al also reported the disordered coupling to a tilt of the TiO 6 -TiO 6 adjacent octahedral that resulted in structural distortion and generation of localized electronic levels above the valence band; these phenomena are mainly responsible for the PL emission of Bi 0.5 K 0.5 TiO 3 materials 51 . Interestingly, the addition of CaFeO 3-δ reduced the PL emission intensity of the Bi 0.5 Na 0.5 TiO 3 materials ( Fig.…”

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confidence: 98%

“…In addition, CaFeO 3-δ -modified Bi 0.5 Na 0.5 TiO 3 materials exhibited smooth absorbance edges with slight tails. The appearance of tails in CaFeO 3-δ -modified Bi 0.5 Na 0.5 TiO 3 materials could be related to an intrinsic defects or surface effects 51 . The optical band gap (E g ) was estimated using the Wood and Tauc method 53 .…”

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Intrinsic and tunable ferromagnetism in Bi0.5Na0.5TiO3 through CaFeO3-δ modification

Hung

Lam

Nguyen

et al. 2020

Sci Rep

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New (1-x)Bi 0.5 na 0.5 tio 3 + xcafeo 3-δ solid solution compounds were fabricated using a sol-gel method. the cafeo 3-δ materials were mixed into host Bi 0.5 na 0.5 tio 3 materials to form a solid solution that exhibited similar crystal symmetry to those of Bi 0.5 na 0.5 tio 3 phases. The random distribution of Ca and fe cations in the Bi 0.5 na 0.5 tio 3 crystals resulted in a distorted structure. The optical band gaps decreased from 3.11 eV for the pure Bi 0.5 na 0.5 tio 3 samples to 2.34 eV for the 9 mol% CaFeO 3-δ -modified Bi 0.5 na 0.5 tio 3 samples. Moreover, the Bi 0.5 na 0.5 tio 3 samples exhibited weak photoluminescence because of the intrinsic defects and suppressed photoluminescence with increasing cafeo 3-δ concentration. Experimental and theoretical studies via density functional theory calculations showed that pure Bi 0.5 na 0.5 tio 3 exhibited intrinsic ferromagnetism, which is associated with the possible presence of Bi, Na, and Ti vacancies and Ti 3+ -defect states. Further studies showed that such an induced magnetism by intrinsic defects can also be enhanced effectively with CaFeO 3-δ addition. This study provides a basis for understanding the role of secondary phase as a solid solution in Bi 0.5 na 0.5 tio 3 to facilitate the development of lead-free ferroelectric materials.The integration of room-temperature ferromagnetic behavior in lead-free ferroelectric materials is a new research trend for the development of green functional materials in smart electronic devices 1,2 . PbTiO 3 -based compounds are one of the most commonly used ferroelectric materials in electronic devices 3 . Therefore, ferroelectric PbTiO 3 -based materials with improved magnetic properties have the potential for the fabrication of next-generation electronic devices.First, the self-organized ferromagnetism of pure ferroelectric PbTiO 3 materials was investigated. The experimental results showed that the weak ferromagnetism in undoped PbTiO 3 nanocrystalline at room temperature resulted from intrinsic defects in events such as O and Ti vacancies 4 . PbTiO 3 thin films also exhibited room-temperature ferromagnetism because of defects in the crystal quality of the film during growth 5 . Shimada et al. predicted that both O and Ti vacancies induce ferromagnetism but through different mechanisms. The ferromagnetism driven by O vacancies originated from the spin-polarized e g state of the nearest Ti atom, whereas that directed by Ti vacancies was attributed to the half-metallic p x state of the nearest O atom 6 . In addition, the ferroelectric property of PbTiO 3 materials at room temperature could be attributed to O vacancies formed on the surfaces, such as vacancies induced ferromagnetism due to local non-stoichiometry and orbital symmetry breaking 7 . Xu et al. conducted first-principle calculations and reported that the O vacancies that formed at the domain wall led to magnetism with a localized spin moment around the vacancies 8 . Second, the conversion of transition metals to ferroelectric PbTiO 3 materials was studied...

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confidence: 98%

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Intrinsic and tunable ferromagnetism in Bi0.5Na0.5TiO3 through CaFeO3-δ modification

Hung

Lam

Nguyen

et al. 2020

Sci Rep

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“…The reduction of the optical bandgap was possible originated from transition metal splitting under crystal field and oxygen vacancies was created due to unbalance charge between transition metal (Co 2+/3+ ) and host (Ti 4+ ) [16]. [17][18][19]. Recent studies of the BKT -BFO and BKT -BCO solid solutions, as well as Fe/Co -doped BKT, also reported the enhancement of the RT magnetic ordering together with the increase of Co/Fe concentration [14,16,17].…”

Section: Resultsmentioning

confidence: 99%

FABRICATION AND PROPERTIES OF Co DOPED Bi0.5K0.5TiO3 – BiFeO3 SOLID SOLUTION

Tuấn¹

2018

JST

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In this study, we present some results on the structure and properties of the solid solution of Bi 0.5 K 0.5 TiO 3 -BiFeCoO 3 (BKT -BFCO) by Sol-gel method. Crystal structures of BKT -BFCO solid solutions were studies by XRD and Raman spectroscopy. The results were in good agreement with the previous reports of Bi 0.5 K 0.5 TiO 3 -BiFeO 3 (BKT -BFO) and Bi 0.5 K 0.5 TiO 3 -BiCoO 3 (BKT -BCO) solid solutions. The magnetic properties were investigated via unsaturated M-H loop, which showed the competition of paramagnetic and antiferromagnetic ordering in BKT -BFCO. However, differing from the BKT -BFO and BKT -BCO solid solutions, the unclear values of saturated magnetism in BKT -BFCO raised the unexplained question, which needed further studies.

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“…BaTiO 3 , BiTiO 3 , and BiFeO 3 , known as a class of ferroelectric materials, were also considered in photocatalytic applications [21][22][23][24][25]. The use of BiFeO 3 /ZnFe 2 O 4 nanocomposites was reported for the photocatalytic degradation of organic dyes under visible light irradiation [26]. To improve the photocatalytic activity, doping at appropriate sites with suitable elements to control the optical properties and band gap of the perovskites has been an effective approach [27].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Bi_0.5Li_0.5TiO₃ Nanoparticles by Sol-Gel Method for Photocatalytic Methylene Blue Degradation and Antibacterial Activity

Phung

Dang

2019

Journal of Nanomaterials

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Facile synthesis of nanomaterials for advanced characterization and application is gaining interest from many researchers. In this study, Bi0.5Li0.5TiO3 nanoparticles were synthesized through the sol-gel method. The photocatalytic activity of the synthesized Bi0.5Li0.5TiO3 was investigated for degradation of methylene blue (MB) under UV irradiation. A photocatalytic efficiency of 74% was found at 150 min when the degradation was performed in the basic media, and the kinetic rate constant was calculated equal to 0.0093 min-1. The antibacterial activity of Bi0.5Li0.5TiO3 nanoparticles was evaluated against E. coli, and the results showed considerable efficiency.

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Tailoring the structural, optical properties and photocatalytic behavior of ferroelectric Bi 0.5 K 0.5 TiO 3 nanopowders

Cited by 42 publications

References 20 publications

Intrinsic and tunable ferromagnetism in Bi0.5Na0.5TiO3 through CaFeO3-δ modification

Intrinsic and tunable ferromagnetism in Bi0.5Na0.5TiO3 through CaFeO3-δ modification

FABRICATION AND PROPERTIES OF Co DOPED Bi0.5K0.5TiO3 – BiFeO3 SOLID SOLUTION

Synthesis of Bi_0.5Li_0.5TiO₃ Nanoparticles by Sol-Gel Method for Photocatalytic Methylene Blue Degradation and Antibacterial Activity

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Tailoring the structural, optical properties and photocatalytic behavior of ferroelectric Bi 0.5 K 0.5 TiO 3 nanopowders

Cited by 42 publications

References 20 publications

Intrinsic and tunable ferromagnetism in Bi0.5Na0.5TiO3 through CaFeO3-δ modification

Intrinsic and tunable ferromagnetism in Bi0.5Na0.5TiO3 through CaFeO3-δ modification

FABRICATION AND PROPERTIES OF Co DOPED Bi0.5K0.5TiO3 – BiFeO3 SOLID SOLUTION

Synthesis of Bi0.5Li0.5TiO3 Nanoparticles by Sol-Gel Method for Photocatalytic Methylene Blue Degradation and Antibacterial Activity

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Synthesis of Bi_0.5Li_0.5TiO₃ Nanoparticles by Sol-Gel Method for Photocatalytic Methylene Blue Degradation and Antibacterial Activity