- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Ferroelectric mesocrystalline BaTiO <sub/>3</sub> /BaBi <sub/>4</sub> Ti <sub/>4</sub> O <sub/>15</sub> nanocomposite: formation mechanism, nanostructure, and anomalous ferroelectric response
摘要： Ferroelectric mesocrystalline nanocomposites are promising materials for the enhancement of ferroelectricity via lattice strain engineering due to their high density of heteroepitaxial interfaces. In the present study, a ferroelectric mesocrystalline BaTiO3/BaBi4Ti4O15 (BT/BBT) nanocomposite was synthesized using the layered titanate H1.07Ti1.73O4 via a facile two-step topochemical process. The BT/BBT nanocomposite is constructed from well-aligned BT and BBT nanocrystals oriented along the [110] and [11?1] crystal-axis directions, respectively. Lattice strain is introduced into the nanocomposite through the formation of a BT/BBT heteroepitaxial interface, which results in a greatly elevated Curie temperature for BBT in the range of 400 °C to 700 °C and an improved piezoelectric response with d*33 = 130 pm V?1. In addition, the BT/BBT nanocomposite is stable up to a high temperature of 1100 °C; therefore, mesocrystalline ceramics can be fabricated as high-performance ferroelectric materials.
关键词： piezoelectric response,nanocomposite,ferroelectric,mesocrystalline,BaBi4Ti4O15,BaTiO3,Curie temperature,lattice strain
更新于2025-09-19 17:15:36
-
Core–shell structured poly(vinylidene fluoride)- <i>grafted</i> -BaTiO <sub/>3</sub> nanocomposites prepared <i>via</i> reversible addition–fragmentation chain transfer (RAFT) polymerization of VDF for high energy storage capacitors
摘要： Core–shell structured poly(vinylidene fluoride)-grafted-barium titanate (PVDF-g-BaTiO3) nanocomposites were prepared by surface-initiated reversible addition–fragmentation chain transfer (RAFT) polymerization of VDF from the surface of functionalized BaTiO3 nanoparticles. The ceramic fillers were first surface-modified with xanthate functions to further allow the RAFT grafting of VDF. A series of structured core shells were synthesized by tuning the feed [initiator functionalized nanoparticles]0 : [monomer]0 ratio, varying from 3 to 5, 10 and 20 wt%. Fourier transform infrared spectroscopy (FTIR), high resolution magic angle spinning (HRMAS) NMR and thermogravimetric analysis (TGA) confirmed the successful surface functionalization of the ceramic filler and the grafting of the PVDF shell onto the surface of the BaTiO3 cores. Transmission electron microscopy results revealed that BaTiO3 nanoparticles are covered by thin shells of PVDF, with thickness varying from 2.2 to 5.1 nm, forming a core–shell structure. HRMAS 19F indicated a grafting of 39–50 units of VDF. X-ray diffraction measurements together with FTIR measurements revealed that PVDF was present in the α form. Thermal properties also indicated that the addition of a small amount of the BaTiO3 filler to the PVDF matrix increased the melting temperature from 168 °C for neat PVDF to 173 °C for PVDF-g-BaTiO3 (20 wt%) and decreased the crystallinity of PVDF from 47% to 21%.
关键词： Nanocomposites,Core-Shell Structure,BaTiO3,PVDF,RAFT Polymerization,Polymer Chemistry,Dielectric Materials
更新于2025-09-19 17:15:36
-
Dielectric and photoluminescence properties of fine-grained BaTiO <sub/>3</sub> ceramics co-doped with amphoteric Sm and valence-variable Cr
摘要： Dielectric and photoluminescence properties of fine-grained BaTiO3 ceramics co-doped with amphoteric Sm and valence-variable Cr (Ba1-xSmx)(Ti1-xCrx)O3 (BSTC) and (Ba1-xSmx)(Ti1-(x-0.01)Crx-0.01)O3 (BSTC1) ceramics with a single-phase perovskite structure were prepared using a traditional solid state based method. The structure, microstructure, site occupations, valence states of Cr, photoluminescence, and dielectric properties of these ceramics were investigated using XRD, SEM, EDXS, RS, EPR, XPS, and dielectric measurements. All ceramics exhibit a fine-grained microstructure (0.7 mm). Three valence states of Cr ions were confirmed and Cr predominates as Cr3+ enter the Ti4+ sites with a stronger EPR signal (1.974). The RS bands of high-wavenumber were attributed to photoluminescence from Sm3+ ions. The formation of SmBa?-CrTi' defect complexes play leading roles in the removal of VO??, prevent the grain growth, and photoluminescence quenching. (Ba1-xSmx)(Ti1-(x-0.01)Crx-0.01)O3 (BSTC1) ceramics with amphoteric Sm3+ ions exhibit a regular diffuse phase transition behavior, rapid Tm-shifting rate of -24.3 °C/at% (Sm/Cr), higher εRT; lower tan δ and x = 0.04 and 0.05 met the EIA Y5V specification.
关键词： Sm and Cr doping,BaTiO3 ceramics,photoluminescence,dielectric properties,co-doping
更新于2025-09-19 17:15:36
-
Complementary Resistive Switching Using Metal-Ferroelectric-Metal Tunnel Junctions
摘要： Complementary resistive switching (CRS) devices are receiving attention because they can potentially solve the current-sneak and current-leakage problems of memory arrays based on resistive switching (RS) elements. It is shown here that a simple anti-serial connection of two ferroelectric tunnel junctions, based on BaTiO3, with symmetric top metallic electrodes and a common, floating bottom nanometric film electrode, constitute a CRS memory element. It allows nonvolatile storage of binary states (“1” = “HRS+LRS” and “0” = “LRS+HRS”), where HRS (LRS) indicate the high (low) resistance state of each ferroelectric tunnel junction. Remarkably, these states have an identical and large resistance in the remanent state, characteristic of CRS. Here, protocols for writing information are reported and it is shown that non-destructive or destructive reading schemes can be chosen by selecting the appropriate reading voltage amplitude. Moreover, this dual-tunnel device has a significantly lower power consumption than a single ferroelectric tunnel junction to perform writing/reading functions, as is experimentally demonstrated. These findings illustrate that the recent impressive development of ferroelectric tunnel junctions can be further exploited to contribute to solving critical bottlenecks in data storage and logic functions implemented using RS elements.
关键词： ferroelectric tunnel junctions,BaTiO3,complementary resistive switching,ferroelectric
更新于2025-09-19 17:15:36
-
Ultrasensitive Paper-Based Photoelectrochemical Sensing Platform Enabled by the Polar Charge Carriers-Created Electric Field
摘要： Efficient separation of electron-hole pairs is vitally crucial to enhancing the analytical performance of paper-based photoelectrochemical (PEC) bioanalysis. Herein, a simple but effective strategy is developed to modulate the effective separation of photogenerated electrons and holes via introducing a polar charge carriers-created (PCC) electric field induced by a classical perovskite ferroelectric BaTiO3 (BTO). By inserting it between the n-type WO3 nanoflakes and p-type Cu2O (WO3 nanoflakes/BTO/Cu2O), the photoelectrode is endowed with a renewable PCC electric field, as a sustaining driving force, to guarantee the realization of directional separation of charge carrier (DSCC) strategy in PEC bioanalysis. The enduring PCC electric field can attract the electrons of Cu2O and holes of WO3, respectively, thereby regulating the directional migration of charge carriers and achieving an enhanced PEC photocurrent for the ultrasensitive quantification based on the highly efficient separation of electron-hole pairs. Consequently, with respect to WO3 nanoflakes/Cu2O and WO3 nanoflakes photoelectrode, the polarized WO3 nanoflakes/BTO/Cu2O photoelectrode exhibits 1.7 and 10.9 times higher photocurrent density, respectively. Benefiting from this, the prominent photocurrent density is obtained which is extremely beneficial for enhancing the sensitivity of PEC bioanalysis. Ultimately, the ultrasensitive detection of model prostate specific antigen (PSA) is realized and presented a linear range of 0.1 pg/mL-50 ng/mL with the detection limitation of 0.036 pg/mL. This work provides the basis for understanding the role of the polarized electric field induced by ferroelectric in tuning the charge separation as well as insights on strategies for constructing high-performance paper-based PEC bioanalysis.
关键词： WO3,BaTiO3,PSA,photoelectrochemical,Cu2O,ferroelectric,bioanalysis
更新于2025-09-19 17:13:59
-
High efficient photovoltaics in BaTiO<sub>3</sub> thin film
摘要： BaTiO3 thin film was grown on a n-type silicon (100) single crystal substrate by high vacuum magnetron sputtering. The samples were annealed under vacuum conditions at 400, 500 and 600°C, respectively. The photovoltaic effect in BaTiO3 thin film was observed, and a high power conversion efficiency of 1.25% was achieved. In addition, the short circuit current density of 134μA/cm2 under white light illumination was obtained in the BaTiO3 thin film. Besides, the current ratio of light ON/OFF state is about 100 at 2v bias. Our experiments suggest that BaTiO3 thin film possesses the potential photovoltaic application in future.
关键词： photovoltaic effect,BaTiO3 thin film,power conversion efficiency
更新于2025-09-11 14:15:04
-
Self‐Polarized BaTiO <sub/>3</sub> for Greatly Enhanced Performance of ZnO UV Photodetector by Regulating the Distribution of Electron Concentration
摘要： ZnO film ultraviolet photodetectors (UV PDs) have always suffered from slow speed and low photosensitivity that restrict their broader applications. To break through those barriers, high-performance ZnO UV PD based on self-polarized BaTiO3 (BTO) is first introduced through a facile one-step spin-coating method. Compared with pure ZnO film UV PD with low on/off ratio (65) and slow speed (4.1/7.5 s) at 3 V bias under 350 nm UV light, the BTO-ZnO bilayer film device exhibits an ultrahigh on/off ratio (14 300) and ultrafast response speed (0.11/5.80 ms), which is much faster than that of the most reported ZnO film-based UV PDs. The numerical simulation demonstrates that the spatial distribution of electron concentration of ZnO film is regulated by the self-polarization of BTO film, resulting in low dark current and fast response time of the BTO-ZnO PD. This work provides a new approach to fabricate high-performance PDs based on self-polarized ferroelectric materials.
关键词： ZnO film,self-polarization,UV photodetector,BaTiO3 film
更新于2025-09-11 14:15:04
-
Design strategy for ferroelectric-based polar metals with dimensionality-tunable electronic states
摘要： Since LiOsO3 was discovered, obtaining easy-accessible polar metals for research and applications has been challenging. In this paper, we present a multilayer design strategy, which is configured as ferroelectric layer/carrier reservoir layer/isolation layer/substrate, for obtaining polar metals by electrostatically doping a strained ferroelectric material in a more effective way. In the proposed configuration, both 1 unit-cell thick BaTiO3 and PbTiO3 exhibited considerable Ti off-centering with various strains, which should extend the applicability of ferroelectric-based polar metals in ultra-thin devices. Moreover, engineered by the compressive strain and the BaTiO3 thickness, the design strategy effectively achieved polar metallicity and dimensionality-tunable electronic states associated with the modulation of highly anisotropic properties such as electrical and electronic thermal conductivity, which may be helpful for designing ultra-thin, ultrafast, and low-power switch devices.
关键词： BaTiO3,design strategy,highly anisotropic conductivity,polar metal,electronic thermal conductivity,electrical conductivity
更新于2025-09-10 09:29:36
-
Influence of additives on structure and ferroelectric properties of NBT-BT-BMT ceramics
摘要： Influence of various over stoichiometric additives on phase formation, unit cell parameters, microstructure, dielectric and ferroelectric properties of solid solutions 0.8[0.8(Na0.5Bi0.5)TiO3-0.2BaTiO3]-0.2Bi(Mg0.5Ti0.5)O3 system has been studied. The unit cell volume slightly decreased in case of the V2O5 additives but did not change in case of Bi2O3, LiF, and KCl additives. Increase in dielectric parameters ert and tandrt values at the room temperature was revealed for compositions doped by KCl additives, while these parameters decreased in compositions doped by the V2O5 additives. Linear correlation between piezoelectric coefficient d33 measured for separate grains using the Piezoresponse Force Microscopy method and dielectric permittivity ert values at the room temperature was confirmed.
关键词： ferroelectric phase transitions,additives,dielectric properties,perovskite structure,Ceramics (Na0.5Bi0.5)TiO3 - BaTiO3 - Bi(Mg0.5Ti0.5)O3
更新于2025-09-10 09:29:36
-
The origin of low bandgap and ferroelectricity of a co-doped BaTiO <sub/>3</sub>
摘要： We recently demonstrated the lowest bandgap ferroelectric, for visible light absorption in BaTi1?x(Mn1/2Nb1/2)xO3, a promising candidate material optoelectronic devices. Using a combination of x-ray spectroscopies and density functional theory (DFT) calculations, we here elucidate this compound’s electronic structure and the modifications induced by Mn doping. In particular, we are able to rationalize how this compound retains its ferroelectricity even through a significant reduction of the optical gap upon Mn doping. The local electronic structure and atomic coordination are investigated using x-ray absorption at the Ti K, Mn K, and O K edges, which suggests only small distortions to the parent tetragonal ferroelectric system, BaTiO3, thereby providing a clue to the substantial retention of ferroelectricity in spite of doping. Features at the Ti K edge, which are sensitive to local symmetry and an indication of Ti off-centering within the Ti-O6 octahedra, show modest changes with doping and strongly corroborates our measured polarization values. Resonant photoelectron spectroscopy results suggest the origin of the reduction of the bandgap in terms of newly created Mn d bands that hybridize with O 2p states. X-ray absorption spectra at the O K edge provide evidence for new states below the conduction band of the parent compound, illustrating additional contributions facilitating bandgap reduction.
关键词： ferroelectricity,Mn doping,x-ray spectroscopies,bandgap,density functional theory,BaTiO3
更新于2025-09-10 09:29:36