Tailoring the microstructure of lead-free KNN piezoelectric ceramics for force-sensitive smart windows

Abstract

Ferro/piezoelectric transparent materials with both excellent piezoelectricity and transparency are of great interest for irreplaceable applications in numerous fields such as photoacoustic imaging and transparent robots. Nevertheless, developing a lead-free ferroelectric ceramic that meets both distinct transparency and high piezoelectricity has always been challenging. Herein, the simple single Sm³⁺ doped KNN ferroelectric ceramics (xSm) are designed to improve transparency and achieve reasonable piezoelectricity. The results indicate that although the donor doping effect of Sm³⁺ significantly improves the transparency by mainly causing grain refinement and densification improvement, it also enhances the relaxor behavior of KNN ceramics and weakens the piezoelectricity. Despite this, with proper Sm doping, reasonable piezoelectricity can still be achieved in the xSm transparent ceramics without causing a significant decrease in Curie temperature. Ultimately, excellent comprehensive performance was achieved in the 1.0 Sm ceramic (T~65% at 900 nm, T_C~395 °C, d₃₃~65 pC/N), competitively in the KNN-based transparent ceramics. In force sensitivity testing, the 1.0 Sm ceramic also exhibits prominent force response electrical output characteristics, which is expected to be applied in smart windows that require real-time pressure detection. This work furnishes a methodology for the fabrication of KNN-based transparent piezoceramics, while contemporaneously recommending innovative perspectives for broadening their range of applications.

Keywords

Transparency / lead-free / KNN-based / piezoelectricity / smart window

References

[1] Ke Y,Lin G.Smart windows: electro-, thermo-, mechano-, photochromics, and beyond.Adv Energy Mater2019;9:1902066

[2] Ke Y,Zhou Y,Chan SH.Emerging thermal-responsive materials and integrated techniques targeting the energy-efficient smart window application.Adv Funct Mater2018;28:1800113

[3] Chen X,Zeng Z.Bio-inspired flexible vibration visualization sensor based on piezo-electrochromic effect.J Materiomics2020;6:643-50

[4] Kim K,Koo B.Surface amending effect of N-doped carbon-embedded NiO films for multirole electrochromic energy-storage devices.Appl Surf Sci2021;537:147902

[5] Wu X,Xu Z.Defect management and multi-mode optoelectronic manipulations via photo-thermochromism in smart windows.Laser Photonics Rev2021;15:2100211

[6] Li J,Daniels J.Lead zirconate titanate ceramics with aligned crystallite grains.Science2023;380:87-93

[7] Wang LV.A practical guide to photoacoustic tomography in the life sciences.Nat Methods2016;13:627-38 PMCID:PMC4980387

[8] Yan P,Xu Z.H Highly transparent Eu-doped 0.72PMN-0.28PT ceramics with excellent piezoelectricity.ACS Appl Mater Interfaces2021;13:54210-6

[9] Gao X,Qiu C.A robust, low-voltage driven millirobot based on transparent ferroelectric crystals.Appl Phys Lett2022;120:032902

[10] Fang Z,Tian X.Ultratransparent PMN-PT electro-optic ceramics and its application in optical communication.Adv Opt Mater2021;9:2002139

[11] Deng C,He C.Reporting excellent transverse piezoelectric and electro-optic effects in transparent rhombohedral PMN-PT single crystal by engineered domains.Adv Mater2021;33:e2103013

[12] Sun E.Relaxor-based ferroelectric single crystals: growth, domain engineering, characterization and applications.Prog Mater Sci2014;65:124-210 PMCID:PMC4104389

[13] Qiu C,Zhang N.Transparent ferroelectric crystals with ultrahigh piezoelectricity.Nature2020;577:350-4

[14] Huangfu G,Wang B.Giant electric field-induced strain in lead-free piezoceramics.Science2022;378:1125-30

[15] Lin J,Xiong R.Tailoring micro-structure of eco-friendly temperature-insensitive transparent ceramics achieving superior piezoelectricity.Acta Mater2022;235:118061

[16] Ren X,Chen B.A compromise between piezoelectricity and transparency in KNN-based ceramics: the dual functions of Li2O addition.J Eur Ceram Soc2020;40:2331-7

[17] Ren X,Zhao X.Relaxor behaviors and electric response in transparent 0.Ceram Int2019;45:3961-8

[18] Kosec M,Hrovat M,Malic B.New lead-free relaxors based on the K_0.5Na_0.5NbO₃-SrTiO₃ solid solution.J Mater Res2004;19:1849-54

[19] Du H,Zhu D.Sintering characteristic, microstructure, and dielectric relaxor behavior of (K_0.5Na_0.5)NbO₃-(Bi_0.5Na_0.5)TiO₃ lead-free ceramics.J Am Ceram Soc2008;91:2903-9

[20] Li F,Gupta S.K_0.5Na_0.5NbO₃-based lead-free transparent electro-optic ceramics prepared by pressureless sintering.J Am Ceram Soc2013;96:3557-62

[21] Li F.Fabrication of transparent electro-optic (K_0.5Na_0.5)_1-xLi_xNb_1-xBi_xO₃ lead-free ceramics.J Eur Ceram Soc2013;33:123-30

[22] Qu B,Yang Z.Lead-free relaxor ferroelectric ceramics with high optical transparency and energy storage ability.J Mater Chem C2016;4:1795-803

[23] Hutchinson M.VASP on a GPU: application to exact-exchange calculations of the stability of elemental boron.Comput Phys Commun2012;183:1422-6

[24] Hacene M,Rozanska X,Guignon T.Accelerating VASP electronic structure calculations using graphic processing units.J Comput Chem2012;33:2581-9

[25] Liu C,Wu X.Boosting upconversion photoluminescence and multielectrical properties via er-doping-modulated vacancy control in Ba_0.85Ca_0.15Ti_0.9Zr_0.1O₃.ACS Omega2019;4:11004-13

[26] Dai Z,Zhou Z.A strategy for high performance of energy storage and transparency in KNN-based ferroelectric ceramics.Chem Eng J2022;427:131959

[27] Rahman A,Min Y.An easy approach to obtain large piezoelectric constant in high-quality transparent ceramics by normal sintering process in modified potassium sodium niobate ceramics.J Eur Ceram Soc2020;40:2989-95

[28] Sun H,Wang X,Hao X.(K,Na)NbO₃ ferroelectrics: A new class of solid-state photochromic materials with reversible luminescence switching behavior.J Mater Chem C2017;5:9080-7

[29] Zhang Q,Wang L,Wang X.A highly efficient, orange light-emitting (K_0.5Na_0.5)NbO₃:Sm³⁺/Zr⁴⁺ lead-free piezoelectric material with superior water resistance behavior.J Mater Chem C2015;3:5275-84

[30] Qiao X,Wu D.A novel multifunctional ceramic with photoluminescence and outstanding energy storage properties.Chem Eng J2021;408:127368

[31] Yang D,Zhang X,Chao X.High transmittance in lead-free lanthanum modified potassium-sodium niobate ceramics.J Alloy Compd2017;716:21-9

[32] Chao X,Zhang X.Excellent optical transparency of potassium-sodium niobate-based lead-free relaxor ceramics induced by fine grains.J Eur Ceram Soc2019;39:3684-92

[33] Zhao X,Wu D,Yang Z.Simultaneous realization of high transparency and piezoelectricity in low symmetry KNN -based ceramics.J Am Ceram Soc2019;102:3498-509

[34] Liu H,Wang H,Zhou C.Er³⁺ and Sr(Bi_0.5Nb_0.5)O₃-modified (K_0.5Na_0.5)NbO₃: a new transparent fluorescent ferroelectric ceramic with high light transmittance and good luminescence performance.Ceram Int2022;48:4230-7

[35] Cheng L,Yao F,Li J.Composition inhomogeneity due to alkaline volatilization in Li-modified (K, Na)NbO₃ lead-free piezoceramics.J Am Ceram Soc2013;96:2693-5

[36] Yang W,Wu S,Shen B.A study on the relationship between grain size and electrical properties in (K, Na)NbO₃-based lead-free piezoelectric ceramics.Adv Elect Mater2019;5:1900570

[37] Ren X,Peng Z.Regulation of energy density and efficiency in transparent ceramics by grain refinement.Chem Eng J2020;390:124566

[38] Pinho R,Zlotnik S.Spark plasma texturing: a strategy to enhance the electro-mechanical properties of lead-free potassium sodium niobate ceramics.Appl Mater Today2020;19:100566

[39] Yang Z,Qu S.Significantly enhanced recoverable energy storage density in potassium-sodium niobate-based lead free ceramics.J Mater Chem A2016;4:13778-85

[40] Li P,Wang F.High piezoelectricity and stable output in BaHfO₃ and (Bi_0.5Na_0.5)ZrO₃ modified (K_0.5Na_0.5)(Nb_0.96Sb_0.04)O₃ textured ceramics.Acta Mater2020;199:542-50

[41] Zhang X,Yang Z.Transparency of K_0.5N_0.5NbO₃-Sr(Mg_1/3Nb_2/3)O₃ lead-free ceramics modulated by relaxor behavior and grain size.Ceram Int2016;42:17963-71

[42] Yang D,Yang Z.Optical and electrical properties of pressureless sintered transparent (K_0.37Na_0.63)NbO₃-based ceramics.Ceram Int2016;42:4648-57

[43] Kwok KW,Lin D.A novel lead-free transparent ceramic with high electro-optic coefficient.Funct Mater Lett2011;4:237-40

[44] Wu X,Kwok K.Photoluminescence, electro-optic response and piezoelectric properties in pressureless-sintered Er-doped KNN-based transparent ceramics.J Alloy Compd2017;695:3573-8

[45] Zhao X,Chen B,Yang Z.Improved transmittance and ferroelectric properties realized in KNN ceramics via SAN modification.J Am Ceram Soc2018;101:5127-37

[46] Liu Y,Yan C,Fan L.A novel transparent material based on KNN ferroelectric ceramics.Ferroelectrics2021;573:173-8

[47] Chai Q,Chao X.Enhanced transmittance and piezoelectricity of transparent K_0.5Na_0.5NbO₃ ceramics with Ca(Zn_1/3Nb_2/3)O₃ additives.RSC Adv2017;7:28428-37

[48] Huang X,Zhang Y.Decoding the intrinsic frequency response behaviors of piezoelectric output current toward advanced sensing and monitoring applications.Nano Energy2025;134:110544

[49] Chen C,Pan C.A method for quantitatively separating the piezoelectric component from the as-received "Piezoelectric" signal.Nat Commun2022;13:1391 PMCID:PMC8927587