Tunable photoluminescence of CaCu3Ti4O12 based ceramics modified with tungsten

Moreno, H.; Cortés, Juan; Praxedes, F.M.; Freitas, Sabrina M. de; Rezende, Marcos V. dos S.; Simões, Alexandre Zirpoli; Teixeira, Verônica C.; Ramírez, M. A.

doi:10.1016/j.jallcom.2020.156652

Cited by 19 publications

(5 citation statements)

References 102 publications

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“…The ratios between Ti 3+ /Ti 4+ of CCTO, TaAl10, and TaAl20 ceramics were 6.91%/93.39%, 5.16%/94.84%, and 4.65%/95.35%, respectively. The presence of Cu + and Ti 3+ is consistent with previous reports [5,33,38].…”

Section: All Elements Casupporting

confidence: 92%

Enhanced giant dielectric properties and improved nonlinear electrical response in acceptor-donor (Al3+, Ta5+)-substituted CaCu3Ti4O12 ceramics

et al. 2021

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The giant dielectric behavior of CaCu3Ti4O12 (CCTO) has been widely investigated owing to its potential applications in electronics; however, the loss tangent (tanδ) of this material is too large for many applications. A partial substitution of CCTO ceramics with either Al3+ or Ta5+ ions generally results in poorer nonlinear properties and an associated increase in tanδ (to ∼0.29–1.15). However, first-principles calculations showed that self-charge compensation occurs between these two dopant ions when co-doped into Ti4+ sites, which can improve the electrical properties of the grain boundary (GB). Surprisingly, in this study, a greatly enhanced breakdown electric field (∼200–6588 V/cm) and nonlinear coefficient (∼4.8–15.2) with a significantly reduced tanδ (∼0.010–0.036) were obtained by simultaneous partial substitution of CCTO with acceptor-donor (Al3+, Ta5+) dopants to produce (Al3+, Ta5+)-CCTO ceramics. The reduced tanδ and improved nonlinear properties were attributed to the synergistic effects of the co-dopants in the doped CCTO structure. The significant reduction in the mean grain size of the (Al3+, Ta5+)-CCTO ceramics compared to pure CCTO was mainly because of the Ta5+ ions. Accordingly, the increased GB density due to the reduced grain size and the larger Schottky barrier height (Φb) at the GBs of the co-doped CCTO ceramics were the main reasons for the greatly increased GB resistance, improved nonlinear properties, and reduced tanδ values compared to pure and single-doped CCTO. In addition, high dielectric constant values (ε′ ≈ (0.52–2.7) × 104) were obtained. A fine-grained microstructure with highly insulating GBs was obtained by Ta5+ doping, while co-doping with Ta5+ and Al3+ resulted in a high Φb. The obtained results are expected to provide useful guidelines for developing new giant dielectric ceramics with excellent dielectric properties.

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Section: All Elements Casupporting

confidence: 92%

Enhanced giant dielectric properties and improved nonlinear electrical response in acceptor-donor (Al3+, Ta5+)-substituted CaCu3Ti4O12 ceramics

et al. 2021

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“…Colossal dielectric permittivity of ceramic oxides with very large dielectric constant (ε > 10 4 ) has been extensively studied for use in electronics applications, especially for capacitive-based devices such as ceramic capacitors [1][2][3][4][5][6][7][8][9][10][11]. Since the colossal dielectric permittivity of CaCu 3 Ti 4 O 12 (CCTO) ceramics was reported by Subramanian, et al [12], many simple and complex oxides such as NiO, ZnO, TiO 2 , SnO 2 , BiFeO 3 , and CCTObased ceramics, have been investigated [1][2][3][13][14][15][16][17][18][19][20][21][22][23][24]. However, these ceramic oxides have limitations for application in electronic devices.…”

Section: Introductionmentioning

confidence: 99%

Effects of Charge Compensation on Colossal Permittivity and Electrical Properties of Grain Boundary of CaCu3Ti4O12 Ceramics Substituted by Al3+ and Ta5+/Nb5+

et al. 2021

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The effects of charge compensation on dielectric and electrical properties of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics (x = 0−0.05) prepared by a solid-state reaction method were studied based on the configuration of defect dipoles. A single phase of CaCu3Ti4O12 was observed in all ceramics with a slight change in lattice parameters. The mean grain size of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics was slightly smaller than that of the undoped ceramic. The dielectric loss tangent can be reduced by a factor of 13 (tanδ ~0.017), while the dielectric permittivity was higher than 104 over a wide frequency range. Impedance spectroscopy showed that the significant decrease in tanδ was attributed to the highly increased resistance of the grain boundary by two orders of magnitude. The DFT calculation showed that the preferential sites of Al and Nb/Ta were closed together in the Ti sites, forming self-charge compensation, and resulting in the enhanced potential barrier height at the grain boundary. Therefore, the improved dielectric properties of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics associated with the enhanced electrical properties of grain boundaries. In addition, the non-Ohmic properties were also improved. Characterization of the grain boundaries under a DC bias showed the reduction of potential barrier height at the grain boundary. The overall results indicated that the origin of the colossal dielectric properties was caused by the internal barrier layer capacitor structure, in which the Schottky barriers at the grain boundaries were formed.

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“…Studies on the properties of calcium-copper-titanate (CaCu3Ti4O12, CCTO) have been progressing very rapidly in recent decades, and it is because of its unique characteristics and promising technological applications. CCTO is well known as a dielectric material with high relative permittivity or dielectric constant and low dielectric loss, which is called giant dielectrics material [1][2][3][4]. Dielectric properties of CCTO are a characteristic that is most studied and investigated to explore its potential applications in electronics technology, including in energy storage devices [5], capacitors [6], gas sensors [7], random access memory [8], and microwave devices [9].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of CaCu3Ti4O12 utilizing eggshell waste as a calcium source: Structure, morphology, and dielectric properties

MADDU¹,

YULWAN²,

SOFIAN³

et al. 2022

J Met Mater Miner

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Calcium copper titanate (CaCu3Ti4O12, CCTO) has been synthesized utilizing eggshell waste as a source of calcium through the hydrothermal route, followed by annealing treatment at temperatures 950°C and 1050°C. The sample with annealing temperatures of 950°C and 1050°C is named CTO-A and CCTO-B, respectively. The structure, microstructure, and dielectric properties of CCTO samples were investigated. The X-ray diffraction analysis results confirmed that the pure phase of CCTO has been successfully synthesized as identified in the diffraction pattern. The average crystallite size of CCTO is quite large due to annealing at high-temperature. The morphology of CCTO by electron microscopy investigation showed the grains tends to agglomerate as the annealing temperature increases due to the solid-state diffusion. Dielectric property investigation showed the CCTO samples have a high dielectric constant at low frequencies and decrease with increasing frequency. Sample CCTO-A annealed at 950oC has a higher dielectric constant than sample CCTO-B annealed at 1050oC, otherwise, it has a lower tangent loss than the sample CCTO-B.

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Tunable photoluminescence of CaCu3Ti4O12 based ceramics modified with tungsten

Cited by 19 publications

References 102 publications

Enhanced giant dielectric properties and improved nonlinear electrical response in acceptor-donor (Al3+, Ta5+)-substituted CaCu3Ti4O12 ceramics

Enhanced giant dielectric properties and improved nonlinear electrical response in acceptor-donor (Al3+, Ta5+)-substituted CaCu3Ti4O12 ceramics

Effects of Charge Compensation on Colossal Permittivity and Electrical Properties of Grain Boundary of CaCu3Ti4O12 Ceramics Substituted by Al3+ and Ta5+/Nb5+

Synthesis of CaCu3Ti4O12 utilizing eggshell waste as a calcium source: Structure, morphology, and dielectric properties

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