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Electric field assisted spray coated lead free bismuth iodide perovskite thin film for solar cell application
摘要： Solution-processed Methylammonium iodo bismuthate (MBI) perovskite solar cell is fabricated by spray technique with changed applied voltages from 0 to 1000 V during the deposition of MBI thin film. The morphology and surface roughness of MBI films are influenced significantly by the electric field during film deposition. It is attributed to improve the atomization of spray droplets due to process of coulomb fission. The surface roughness of MBI film is reduced from 39 to 19 nm with increased applied voltages during the deposition from 0 V and 1000 V, respectively. A strong absorption band is observed ～500 nm for all MBI films. The MBI perovskite solar cell is showed enhancement in the efficiency with the maximum current density 2.33 mA/cm2 at 1000 V applied voltage during the deposition. The improvement in photovoltaic characteristics with applied voltage during the film deposition is attributed to the formation of more uniform film with improved surface morphology and roughness, resulting in efficient electron transfer and reduced recombination of charge carrier at grain boundaries.
关键词： Methyl ammonium bismuth (III) iodide,Spray deposition,Perovskite solar cell,Electric filed,Lead free perovskite
更新于2025-11-21 11:18:25
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Enhanced energy storage performance in Sn doped Sr0.6(Na0.5Bi0.5)0.4TiO3 lead-free relaxor ferroelectric ceramics
摘要： SnO2 doped Sr0.6(Na0.5Bi0.5)0.4TiO3 (NBT-ST) ceramics were prepared by a conventional solid-state reaction method. Their phase structures, microstructures and electrical properties were characterized in details. It is found that SnO2 doping could increase the lattice parameters, density and average grain size. A suitable amount of SnO2 can improve dielectric properties, and affect the relaxor behavior of the NBT-ST matrix, thereby it can effectively reduce the energy loss and optimize the energy storage performance. Furthermore, the energy storage properties are improved with SnO2 doping. Especially, the 1 at. % SnO2 doped NBT-ST achieves a high recoverable energy density of 2.35 J/cm3, which is mainly attributed to large maximum polarization of 43.2 μC/cm2, small remnant polarization of 5.83 μC/cm2 and high breakdown strength of 180 kV/cm. Also, relatively good temperature stability for dielectric performance and excellent fatigue resistance are observed in this composition. These properties are attractive for lead-free energy storage applications.
关键词： SnO2,Lead-free,Dielectric,Energy storage,NBT-ST
更新于2025-11-14 17:28:48
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Controlling colloidal processing of (K,Na)NbO3-based materials in aqueous medium
摘要： K0.5Na0.5NbO3-based materials are serious candidates to replace lead-based piezoceramics since they show excellent electrical and piezoelectric properties. The tape casting technique can be used to obtain highly textured KNN-based ceramics; however, despite industrial and environmental advantages of water-based processing, there are not reports about the control of colloidal processing conditions to obtain optimized K0.5Na0.5NbO3-based slurries in aqueous medium. This paper reports a procedure for controlling colloidal processing conditions to obtain optimized (K0.5Na0.5)0.97Li0.03Nb0.8Ta0.2O3 suspensions. Zeta potential and cationic solubility measurements as a function of pH showed that pH 8.5 is adequate for controlling colloidal stability and rheological behavior of aqueous suspensions, while flow curves analysis allowed optimizing processing parameters, such as, powder content, amount of deflocculant and binder, and sonication time. Optimized colloidal suspensions were prepared and used to obtain high quality tapes. Processed ceramics from these stacked tapes show equivalent properties to those processed directly from powders, which demonstrates the effectiveness of the colloidal route reported here.
关键词： Aqueous tape casting,KNN,Lead-free,Rheological properties,Colloidal suspensions
更新于2025-11-14 17:28:48
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Evolving antiferroelectric stability and phase transition behavior in NaNbO3-BaZrO3-CaZrO3 lead-free ceramics
摘要： The stability of antiferroelectricity in NaNbO3 ceramics was found to evolve with co-doping x mol% CaZrO3 and 6 mol% BaZrO3, from a dominant ferroelectric (FE) orthorhombic Q phase (x=0) to a gradually stabilized antiferroelectric (AFE) orthorhombic P phase owing to different ionic radii of Ba and Ca ions. Although a complete AFE P phase appears at x=0.5, the field induced AFE-FE phase transformation is irreversible at first, and then becomes partially reversible at x=1 and finally completely reversible at x=3. The above-mentioned change process proves to be associated with the enhancing stability of antiferroelectricity with x, as evidenced by means of dielectric, polarization and strain properties as well as in/ex-situ synchrotron x-ray diffraction and Raman spectra. A composition-field phase diagram for the NN-based lead-free AFE ceramic was constructed on basis of the phase structural change, which would provide a clear understanding of how ion doping influences its antiferroelectricity.
关键词： lead-free ceramics,Antiferroelectricity,phase transition,NaNbO3
更新于2025-11-14 17:28:48
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Luminescence and electrical properties of Eu-modified Bi <sub/>0.5</sub> Na <sub/>0.5</sub> TiO <sub/>3</sub> multifunctional Ceramics
摘要： The Eu3+ modified Bi0.5Na0.5TiO3 (BNT) ceramics have been fabricated by the solid-state reaction method. The impact of Eu3+ doping on the structure, photoluminescence and electrical properties has been studied by XRD, SEM, PL spectra and LCR meter. X-ray diffraction analysis reveals that the crystal structure of the samples is well matched with the trigonal perovskite, and the optimal temperature of pre-sintering is 880°C. The Eu3+ doped BNT ceramics show excellent red fluorescence at 614nm corresponding to the 5D0→7F2 transition of Eu3+ under 466nm excitation and relatively long fluorescence lifetime. The BNT-0.02Eu ceramic density is up to 5.68g/cm3 and the relative density is up to 94.6% with sintering temperature 1075°C. The piezoelectric constant (d33) of samples has been significantly improved up to 110pC/N by Eu3+ doping. The BNT-0.03Eu ceramic pre-sintered at 880°C and sintered at 1050°C has good dielectric properties and excellent luminescence properties. Eu3+ doped BNT ceramics make it potential applications for novel integrated optical-electro and multifunctional devices.
关键词： luminescence,electrical properties,Bismuth sodium titanate (Bi0.5Na0.5TiO3),lead-free ceramics
更新于2025-11-14 17:28:48
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Enhanced breakdown strength and energy storage density in a new BiFeO3-based ternary lead-free relaxor ferroelectric ceramic
摘要： A new ternary lead-free relaxor ferroelectric ceramic of (0.67-x)BiFeO3-0.33(Ba0.8Sr0.2)TiO3-xLa(Mg2/3Nb1/3)O3+y wt.% MnO2+z wt.% BaCu(B2O5) (BF-BST-xLMN+y wt.% MnO2+z wt.% BCB) was prepared by a solid-state reaction method. The substitution of LMN for BF was believed to induce a typical dielectric relaxation behavior owing to the increased random fields. After co-doping MnO2 and BCB, a significant decrease in the conductivity and grain size was simultaneously realized, resulting in obviously enhanced dielectric breakdown strength and energy-storage performances at room temperature. A high recoverable energy storage density W~3.38 J/cm3 and an acceptable energy storage efficiency η~59% were achieved in the composition with x=0.06, y=0.1 and z=2 under a measuring electric field of 23 kV/mm. In addition, the energy-storage performance is quite stable against both frequency (0.1 Hz-100 Hz) and temperature (30-170 oC), suggesting that BF-BST-xLMN+y wt.% MnO2+z wt.% BCB lead-free relaxor ferroelectric ceramics might be a promising dielectric material for high-power pulsed capacitors.
关键词： Lead-free ceramics,Relaxor ferroelectrics,Energy storage,BiFeO3,BDS
更新于2025-11-14 17:28:48
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Effect of NaNbO <sub/>3</sub> Crystals on the Electrical Properties of Na <sub/>0.47</sub> K <sub/>0.47</sub> Li <sub/>0.06</sub> NbO <sub/>3</sub> Ceramics Synthesised by Seed Induced Method
摘要： In this work, we investigated the influence of crystalline NaNbO3 on the electrical properties of Na0.47K0.47Li0.06NbO3 (NKLN) ceramics. Preparation by the conventional method for the upcoming phase of random elements did not control the properties. For this reason, we studied the electrical properties and phase formation that occurred with the addition of NaNbO3 crystals, used at the initial phase of the reaction, in order to modify the electrical properties of NKLN ceramics. We synthesized lead-free piezoelectric ceramics by the seed-induced method. We prepared the NaNbO3 crystals used as seeds by molten salt synthesis (MSS). We mixed the powder oxides of Na2CO3 and Nb2O5 with NaCl oxides-salt ratio 1:6. The seeds varied in content from 0 to 20 mol%. The calcination temperature of NKLN was from 800 to 900 °C for 10 h, using two-step sintering (TSS) techniques. Our investigation further reported on the microstructure and the electrical properties. The results showed high Curie temperature of about 480 °C, while the effect of the seed crystal improved the piezoelectric properties of the samples, compared with the conventional mixed-oxide.
关键词： Seed-Induced Method,NKLN,Lead-Free Ceramic,NaNbO3
更新于2025-11-14 17:28:48
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Structure-design strategy of 0–3 type (Bi0.32Sr0.42Na0.20)TiO3/MgO composite to boost energy storage density, efficiency and charge-discharge performance
摘要： A novel 0–3 type (Bi0.32Sr0.42Na0.20)TiO3/MgO composite is investigated in this work, which possesses a high stored energy storage density ws?2.50 J/cm3, recoverable energy storage density WR?2.09 J/cm3 with high efficiency η?84% under low electric field (20 kV/mm). The excellent performance is owning to the increase of breakdown strength (BDS) value and the intrinsic mechanism for enhanced BDS value by MgO incorporation is disclosed by numerical simulations (COMSOL). Moreover, the studied composite exhibits excellent charge-discharge performance, the current density (CD) and power density (PD) are 1671 A/cm2 and 150 MW/cm3, respectively, which are much superior to that of other ceramics. Besides, most of the stored energy is discharged within ?0.15 μs via charge-discharge tests. This work not only provides a novel technique to designing bismuth-based ceramic capacitors with simultaneously high Wd, η and excellent charge-discharge performance, but also deepens the understandings of the role for the metallic oxide in the composite.
关键词： 0–3 Composite,Energy storage,Numerical simulations,Charge-discharge,Lead-free
更新于2025-11-14 17:28:48
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(Bi0.51 Na0.47)TiO3 based lead free ceramics with high energy density and efficiency
摘要： Dielectric ceramics with high energy storage density and energy efficiency play an important role in high power energy storage applications. In this work, lead free relaxor ferroelectric ceramics in (1-x)Bi0.51Na0.47TiO3-xBa(Zr0.3Ti0.7)O3 (BNT-BZT100x: x=0.20, 0.30, 0.40 and 0.50) system are fabricated by conventional solid-state sintering method. The BNT-BZT100x ceramics are sintered dense with minimal pores, exhibiting pseudocubic symmetry and strong relaxor characteristic. A very high energy storage density of 3.1 J/cm3 and high energy efficiency of 91% are simultaneously achieved in BNT-BZT40 ceramic with 0.1mm in thickness, at the applied electric field of 280 kV/cm. The temperature stability of the energy density is studied over temperature range of 20-160°C, showing minimal variation below 1.5%, together with the excellent cycling reliability (the variations of both energy density and efficiency are below 3% up to 106 cycles), making BNT-BZT40 ceramic promising as a candidate for high-temperature dielectric and energy storage applications.
关键词： relaxor characteristic,lead free ceramic,energy storage
更新于2025-11-14 17:28:48
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High electromechanical strain properties in SrTiO3?modified Bi1/2Na1/2TiO3?KTaO3 lead?free piezoelectric ceramics under low electric field
摘要： This study investigated the structures, dielectric, ferroelectric and piezoelectric properties of (0.99?x)Bi1/2Na1/2TiO3?0.01KTaO3?xSrTiO3 (BNT?KT?100xST, x = 0.20 ~ 0.235) lead?free piezoelectric ceramics. These piezoceramics were synthesized by conventional solid?state reaction method. As a consequence, a large electrical strain and normalized strain (d33* ≈ 793 pm/V) can be obtained even under 3 kV/mm as low electric field for BNT?KT?22.5ST ceramics. The phase transition between nonergodic relaxor (NER) and ergodic relaxor (ER) under electric field might be responsible for its large strain. It means that BNT?KT?100xST lead?free ceramics can be a promising candidate for actuator applications.
关键词： Phase transition,Lead-free,Ternary system,Piezoelectric ceramics,Relaxor
更新于2025-11-14 17:28:48