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Saha M, Niranjan MK, Asthana S. Polarized Raman, infrared and dielectric spectra of lead-free K 0.5Na 0.5NbO 3piezoelectric system: insights from ab-initiotheoretical and experimental studies. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:425703. [PMID: 38986476 DOI: 10.1088/1361-648x/ad61aa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Accepted: 07/10/2024] [Indexed: 07/12/2024]
Abstract
The K0.5Na0.5NbO3(KNN) system has emerged as one of the most promising lead-free piezoelectric over the years. In this work, we perform a comprehensive investigation of electronic structure, lattice dynamics and dielectric properties of room temperature phase of KNN by combiningab-initioDFT based theoretical analysis and experimental characterization. We assign the symmetry labels to KNN vibrational modes and obtainab-initiopolarized Raman spectra, Infrared reflectivity, Born-effective charge tensors, oscillator strengths etc. The KNN ceramic samples are prepared using conventional solid-state method and Raman and UV-Vis diffuse reflectance spectra are obtained. The computed Raman spectrum is found to agree well with the experimental spectrum. In particular, the results suggest that the mode in range ∼840-870 cm-1reported in the experimental studies is longitudinal optical withA1symmetry. The Raman mode intensities are calculated for different light polarization set-ups that suggests the observation of different symmetry modes in different polarization set-ups. The electronic structure of KNN is investigated and optical absorption spectrum is obtained. Further, the performances of DFT semi-local, meta-GGA and hybrid exchange-correlations functionals, in the estimation of KNN band gaps are investigated. The KNN bandgap computed using GGA-1/2 and HSE06 hybrid functional schemes are found to be in excellent agreement with the experimental value. The COHP, electron localization function and Bader charge analysis is also performed to deduce the nature of chemical bonding in the KNN. Overall, our study provides several bench-mark important results on KNN that have not been reported so far.
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Affiliation(s)
- Manish Saha
- Theoretical Nanoscience Group, Department of Physics, Indian Institute of Technology Hyderabad, Kandi, Telangana 502284, India
- Advanced Functional Materials Laboratory, Department of Physics, Indian Institute of Technology Hyderabad, Kandi, Telangana 502284, India
| | - Manish K Niranjan
- Theoretical Nanoscience Group, Department of Physics, Indian Institute of Technology Hyderabad, Kandi, Telangana 502284, India
| | - Saket Asthana
- Advanced Functional Materials Laboratory, Department of Physics, Indian Institute of Technology Hyderabad, Kandi, Telangana 502284, India
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Czaja P, Szostak E, Hetmańczyk J, Zachariasz P, Majda D, Suchanicz J, Karolus M, Bochenek D, Osińska K, Jędryka J, Kityk A, Piasecki M. Thermal Stability and Non-Linear Optical and Dielectric Properties of Lead-Free K 0.5Bi 0.5TiO 3 Ceramics. MATERIALS (BASEL, SWITZERLAND) 2024; 17:2089. [PMID: 38730896 PMCID: PMC11084477 DOI: 10.3390/ma17092089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Revised: 04/04/2024] [Accepted: 04/16/2024] [Indexed: 05/13/2024]
Abstract
Lead-free K0.5Bi0.5TiO3 (KBT) ceramics with high density (~5.36 g/cm3, 90% of X-ray density) and compositional purity (up to 90%) were synthesized using a solid-state reaction method. Strongly condensed KBT ceramics revealed homogenous local microstructures. TG/DSC (Thermogravimetry-differential scanning calorimetry) techniques characterized the thermal and structural stability of KBT. High mass stability (>0.4%) has proven no KBT thermal decomposition or other phase precipitation up to 1000 °C except for the co-existing K2Ti6O13 impurity. A strong influence of crystallites size and sintering conditions on improved dielectric and non-linear optical properties was reported. A significant increase (more than twice) in dielectric permittivity (εR), substantial for potential applications, was found in the KBT-24h specimen with extensive milling time. Moreover, it was observed that the second harmonic generation (λSHG = 532 nm) was activated at remarkably low fundamental beam intensity. Finally, spectroscopic experiments (Fourier transform Raman and far-infrared spectroscopy (FT-IR)) were supported by DFT (Density functional theory) calculations with a 2 × 2 × 2 supercell (P42mc symmetry and C4v point group). Moreover, the energy band gap was calculated (Eg = 2.46 eV), and a strong hybridization of the O-2p and Ti-3d orbitals at Eg explained the nature of band-gap transition (Γ → Γ).
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Affiliation(s)
- Piotr Czaja
- Institute of Technology, University of the National Education Commission, Podchorążych 2, 30-084 Krakow, Poland
| | - Elżbieta Szostak
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland; (J.H.); (D.M.)
| | - Joanna Hetmańczyk
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland; (J.H.); (D.M.)
| | - Piotr Zachariasz
- Center for Hybrid Microelectronics and LTCC, Łukasiewicz Research Network—Institute of Microelectronics and Photonics, Zabłocie 39, 30-701 Krakow, Poland;
| | - Dorota Majda
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland; (J.H.); (D.M.)
| | - Jan Suchanicz
- Department of Mechanical Engineering and Agrophysics, University of Agriculture in Krakow, Balicka 120, 31-120 Krakow, Poland;
| | - Małgorzata Karolus
- Faculty of Science and Technology, Institute of Materials Engineering, University of Silesia in Katowice, 75 Pułku Piechoty 1a, 41-500 Chorzow, Poland; (M.K.); (D.B.); (K.O.)
| | - Dariusz Bochenek
- Faculty of Science and Technology, Institute of Materials Engineering, University of Silesia in Katowice, 75 Pułku Piechoty 1a, 41-500 Chorzow, Poland; (M.K.); (D.B.); (K.O.)
| | - Katarzyna Osińska
- Faculty of Science and Technology, Institute of Materials Engineering, University of Silesia in Katowice, 75 Pułku Piechoty 1a, 41-500 Chorzow, Poland; (M.K.); (D.B.); (K.O.)
| | - Jarosław Jędryka
- Faculty of Electrical Engineering, Czestochowa University of Technology, Armii Krajowej 17, 42-201 Czestochowa, Poland; (J.J.); (A.K.)
| | - Andriy Kityk
- Faculty of Electrical Engineering, Czestochowa University of Technology, Armii Krajowej 17, 42-201 Czestochowa, Poland; (J.J.); (A.K.)
| | - Michał Piasecki
- Institute of Physics, Jan Dlugosz University, Armii Krajowej 13/15, 42-200 Czestochowa, Poland;
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Piezoelectric Ceramic/Photopolymer Composites Curable with UV Light: Viscosity, Curing Depth, and Dielectric Properties. JOURNAL OF COMPOSITES SCIENCE 2022. [DOI: 10.3390/jcs6070212] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Four piezoelectric ceramic materials with varying particle sizes and geometries are added up to 30 vol.% to a photopolymer resin to form UV-curable piezoelectric composites. Such composites solidify in a few minutes, can be used in UV-curing-based 3D printing processes, and can achieve improved sensor performance. The particle dispersion with ultrasonication shows the most homogeneous particle dispersion with ethanol, while two other solvents produced similar results. The viscosities of the prepared suspensions show some dependency on the particle size. The curing depth results show a strong dependency on the ceramic particle size, the difference in refractive index, and the particle size distribution, whereby composites filled with PZT produced the worst results and composites filled with KNN produced the highest curing depths. The SEM images show a homogeneous dispersion of ceramic particles. The highest dielectric properties are also shown by KNN-filled composites, while BTO and PZT produced mixed results of dielectric constants and dielectric losses. KNN-filled composites seem to be very promising for further 3D-printable, lead-free piezoelectric composite development.
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Espinosa AP, Ramajo L, Rubio-Marcos F, Macchi C, Somoza A, Castro M. Influence of the BaTiO3 addition to K0.5Na0.5NbO3 lead-free ceramics on the vacancy-like defect structure and dielectric properties. Ann Ital Chir 2021. [DOI: 10.1016/j.jeurceramsoc.2020.10.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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