Hydrothermal crystal growth, piezoelectricity, and triboluminescence of KNaNbOF5

Chang, Kelvin B.; Edwards, Bryce W.; Frazer, Laszlo; Lenferink, Erik J.; Stanev, Teodor K.; Stern, Nathaniel P.; Nino, Juan C.; Poeppelmeier, Kenneth R.

doi:10.1016/j.jssc.2015.07.011

Cited by 12 publications

(13 citation statements)

References 28 publications

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“…Compared with ZnO, the piezoelectric constants of α-KNaNbOF 5 are much lower. In order to make a comparison to the experimental piezoelectric response measurement reported in [ 9 ], the calculated piezoelectric stress matrix [ e ] is converted into the piezoelectric strain matrix [ d ] by the relationship [ e ] = [ c ][ d ], where [ c ] is the elastic matrix. Based on Table 4 and Table 5 , the calculated d z3 is 1.5 pC/N, which is lower than the experimental value 6.7 pC/N [ 9 ].…”

Section: Resultsmentioning

confidence: 99%

“…In order to make a comparison to the experimental piezoelectric response measurement reported in [ 9 ], the calculated piezoelectric stress matrix [ e ] is converted into the piezoelectric strain matrix [ d ] by the relationship [ e ] = [ c ][ d ], where [ c ] is the elastic matrix. Based on Table 4 and Table 5 , the calculated d z3 is 1.5 pC/N, which is lower than the experimental value 6.7 pC/N [ 9 ]. Since our calculated lattice parameters, atomic positions, and relative permittivity agree well with experiments, the errors in the calculated d z3 may originate from three aspects: (1) The experiment was carried out at room temperature—since finite temperatures are not included in the calculation, the calculated value of d z3 is smaller than that observed in experiments; (2) The value of d z3 is sensitive to the crystal structure—the calculated lattice constants deviate from the experimental values by ~1%, which affects the evaluation of d z3 ; (3) Compared to other commonly used piezoelectric materials, such as BaTiO 3 (~190 pC/N) and K 0.5 Na 0.5 NbO 3 (~160 pC/N) [ 9 ], the d z3 value of KNaNbOF 5 is much lower.…”

Section: Resultsmentioning

confidence: 99%

“…Secondly, KNaNbOF 5 is also a triboluminescent material. It was reported that strong triboluminescence can be visible to the naked eye under normal lighting conditions [ 9 ]. Last but not least, KNaNbOF 5 has attracted great interest due to its polymorphism [ 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

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Piezoelectric, Mechanical and Acoustic Properties of KNaNbOF5 from First-Principles Calculations

et al. 2015

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Recently, a noncentrosymmetric crystal, KNaNbOF5, has attracted attention due to its potential to present piezoelectric properties. Although α- and β-KNaNbOF5 are similar in their stoichiometries, their structural frameworks, and their synthetic routes, the two phases exhibit very different properties. This paper presents, from first-principles calculations, comparative studies of the structural, electronic, piezoelectric, and elastic properties of the α and the β phase of the material. Based on the Christoffel equation, the slowness surface of the acoustic waves is obtained to describe its acoustic prosperities. These results may benefit further applications of KNaNbOF5.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Piezoelectric, Mechanical and Acoustic Properties of KNaNbOF5 from First-Principles Calculations

et al. 2015

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“…17 Taking into account the ionic radii ratio with cations in A and B sites, for r(A n+ )/r(B m+ ) > 1.80, the 3D or 2D perovskite network is generally stabilized whereas the pyrochlore structure is obtained for 1.46 < r(A n+ )/r(B m+ ) < 1.80 and finally the fluorite framework is favored for r(A n+ )/r(B m+ ) < 1. 46. The introduction of vacancies at the A site promotes cation ordering and the formation of superstructures evidenced, for instance, in tetragonal or hexagonal tungsten bronzes.…”

Section: Introductionmentioning

confidence: 99%

“…42,43 Polar phases can be stabilized as sodium cations are partly substituted for lithium (Li x Na 1-x NbO 3 ) 44 and also when fluorine substitutes partially oxygen (KNaNbOF 5 ). 45,46 No Ti-substituted sodium niobate with a polar structure has ever been reported so far. In the present work, the synthesis of NaNb 1-x Ti x O 3-0.5x , 0 < x ≤ 0.20 is reported, starting with hydrothermal conditions.…”

Section: Introductionmentioning

confidence: 99%

High Ionic Conductivity in Oxygen-Deficient Ti-Substituted Sodium Niobates and the Key Role of Structural Features

et al. 2019

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NaNb 1-x Ti x O 3-0.5x (0 < x ≤ 0.15) compounds were prepared using a two-step synthesis involving a hydrothermal route at T = 200 °C in an autoclave followed by heat treatments under air or reductive conditions. Rietveld structural refinements from Xray diffraction data combined with 23 Na and 93 Nb nuclear magnetic resonance evidenced the formation of new complex oxides crystallizing in the P2 1 ma space group. Ti substitution for Nb atoms contributes to stabilize the acentric polymorph rather than the well-known thermodynamically stabilized network (Pbma space group) of sodium niobate. Taking into account the competitive bonds sequences Na1(2)-O1(2)-Nb-O3(4), the large variation of Na1-O1 and Na2-O2 bond lengths after Ti substitution leads to reduce the Nb/Ti-O1 and Nb/Ti-O2 apical distortion (elongation in one direction) and consequently to exalt the distortion in the equatorial plane. Then, the transition metal crystal-field splitting increases as well as the second-order Jahn-Teller effect and the optical band gap red-shifts to visible range starting with low Ti content. Two phase-transition sequences at moderated temperature are characterized by the relaxation of the perovskite framework with various [Nb(Ti)O 6 ] octahedral distortion and tilt modes: from the polar orthorhombic P2 1 ma phase to the centrosymmetric orthorhombic Cmcm network above T = 300 °C and then to the ideal cubic perovskite structure above T = 600°C. The pronounced decrease of phase transition temperature with Ti substitution, especially from P2 1 ma to Cmcm, was correlated to the almost identical stabilities of the two Na sites and the four oxygen positions in P2 1 ma symmetry but also to larger distortion of the transition metal polyhedron enhancing the oxygen mobility. Moreover, the high ionic conductivity of oxygen-deficient NaNb 1-x Ti x O 3-0.5x was evidenced for the first time between 300 and 700 °C (σ ion (T = 300 °C) = 3 10 -5

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Functional Modules Map of Unexplored Chemical Space: Guiding the Discovery of Giant Birefringent Materials

Tudi,

Li,

Xie

et al. 2024

Adv Funct Materials

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Finding birefringent material with giant optical anisotropy is urgent for photonic applications. However, the application of existing birefringent materials is limited by restricted transparency wavelength or optical anisotropy. The process of trial and error is time‐consuming and inefficient in terms of resources, especially when compared to the vast design spaces for materials. The immense chemical space necessitates a high‐throughput approach for giant optical anisotropy materials design. Here, a full‐applied wavelength map of birefringent materials is constructed, from conventional visible expanding to ultraviolet and deep‐ultraviolet region by high‐throughput screening methods. And highlighted 579 materials birefringence exceeds the one of available commercial birefringent materials in corresponding regions. Significantly, 54 materials possess giant birefringence above 0.5 @1064 nm. Via developing a high‐throughput screening technique for microscopic structures with given coordination number, the study further characterizes a comprehensive map of functional modules featuring birefringent activeness. According to the macroscopic and microscopic dual‐functional maps, and a novel crystal Li2(HC3N3S3)∙5H2O with birefringence difference 0.532 @546 nm is designed and synthesized successfully. This study identifies desired materials with high performance in unheeded chemical spaces.

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Hydrothermal crystal growth, piezoelectricity, and triboluminescence of KNaNbOF5

Abstract: 2016-11-02T18:49:00

Cited by 12 publications

References 28 publications

Piezoelectric, Mechanical and Acoustic Properties of KNaNbOF5 from First-Principles Calculations

Piezoelectric, Mechanical and Acoustic Properties of KNaNbOF5 from First-Principles Calculations

High Ionic Conductivity in Oxygen-Deficient Ti-Substituted Sodium Niobates and the Key Role of Structural Features

Functional Modules Map of Unexplored Chemical Space: Guiding the Discovery of Giant Birefringent Materials

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