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Racemic Amino Acid Piezoelectric Transducer
摘要： Single crystal L-amino acids can exhibit technologically useful piezoelectric and nonlinear optical properties. Here we predict, using density functional theory, the piezoelectric charge and strain and voltage tensors of the racemic amino acid DL alanine, and use the modeling data to guide the first macroscopic and nanoscopic piezoelectric measurements on DL-alanine single crystals and polycrystalline aggregates. We demonstrate voltage generation of up to 0.8 V from DL-alanine crystal films under simple manual compression, twice as high as other amino acid crystals. Our results suggest that net molecular chirality is not a prerequisite for piezoelectric behavior in organic crystals. The transducer presented herein demonstrates that DL-alanine crystals can be used in applications such as temperature and force measurement in biosensors, data storage in flexible electronic devices, and mechanical actuation in energy harvesters.
关键词： Energy harvesting,Amino acids,Piezoelectricity,Density functional theory,DL-alanine
更新于2025-09-19 17:15:36
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Symmetry-breaking induced large piezoelectricity in Janus tellurene materials
摘要： Symmetry-breaking induced large piezoelectricity in Janus tellurene materials. Structural symmetry-breaking can lead to novel electronic and piezoelectric properties in two-dimensional (2D) materials. In this paper, we propose a 2D Janus tellurene (Te2Se) monolayer with asymmetric Se/Te surfaces and its derived multilayer structures. The band structure calculations show that the 2D Janus Te2Se monolayer is an indirect gap semiconductor, and the intrinsic mirror asymmetry combined with the spin–orbit coupling induces the Rashba spin splitting and the out-of-plane spin polarization. Moreover, the absence of both the inversion symmetry and out-of-plane mirror symmetry, together with flexible mechanical properties, results in large in-plane and out-of-plane piezoelectric coefficients that are valuable in 2D piezoelectric materials. Furthermore, the out-of-plane piezoelectric effects can exist in multilayer structures under different stacking sequences while the in-plane piezoelectric effect can only exist in some specific stacking patterns. The piezoelectric coefficients of the Janus Te2Se monolayer and multilayers exceed those of many Janus transition metal dichalcogenides and other well-known piezoelectric materials (e.g., a-quartz and wurtzite-AlN). The combination of the SOC-induced spin splitting and large piezoelectricity endows the Janus Te2Se structures with potential for applications in spintronics, flexible electronics and piezoelectric devices.
关键词： spintronics,2D materials,Janus tellurene,symmetry-breaking,piezoelectricity
更新于2025-09-19 17:15:36
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Optimized Polyvinylidene Fluoride Nanofiber Webs for Flexible Energy Harvesters
摘要： This work reports the process optimization of various electrospinning parameters to fabricate polyvinylidene fluoride based piezoelectric flexible nanofiber webs for passive sensing and energy harvesting applications. Process parameters like electrospinning voltage and drum speed have been taken into consideration while optimizing the electrospun nanofiber webs for maximizing their piezoelectric property. Finally, the optimized recipe is used to fabricate a flexible PVDF nanofiber energy harvester to demonstrate the energy harvesting capability of such nanofiber webs.
关键词： nanofiber,electrospinning,polyvinylidene fluoride (PVDF),piezoelectricity,sensor
更新于2025-09-19 17:15:36
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Giant Piezoelectricity of Ternary Perovskite Ceramics at High Temperatures
摘要： Here, novel ferroelectric ceramics of (0.95 ? x)BiScO3-xPbTiO3-0.05Pb(Sn1/3Nb2/3)O3 (BS-xPT-PSN) of complex perovskite structure are reported with compositions near the morphotropic phase boundary (MPB), and which exhibit a piezoelectric coefficient d33 = 555 pC N?1, a large-signal coefficient *d33 ≈ 1200 pm V?1 at room temperature, and a high Curie temperature TC of 408 °C. More interestingly, this ternary system exhibits a giant and stable piezoelectric response at 200 °C with a large-signal *d33 ≈ 2500 pm V?1, matching that of the costly relaxor-based piezoelectric single crystals at room temperature. The mechanisms of such giant piezoelectricity and its characteristic temperature dependence are attributed to the spontaneous polarization rotation and extension under an electric field and the MPB-related phase transition. The findings reveal that the BS-xPT-PSN ceramics constitute a new family of high-performance piezoelectric materials suitable for electromechanical transducers that can be operated at high temperatures (at 200 °C, or higher).
关键词： giant piezoelectricity,relaxor ferroelectric,high temperatures
更新于2025-09-19 17:15:36
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Motile Piezoelectric Nanoeels for Targeted Drug Delivery
摘要： The field of small-scale robotics is undergoing a paradigm shift toward the use of soft smart materials. The integration of soft smart components in micro- and nanorobotic platforms not only allows for more sophisticated locomotion mechanisms, but also more closely mimicks the functioning of biological systems. A soft hybrid nanorobot that mimics an electric eel, a knifefish with an elongated cylindrical body that is able to generate electricity during its motion, is presented here. These nanoeels consist of a flexible piezoelectric tail composed of a polyvinylidene fluoride–based copolymer, linked to a polypyrrole nanowire, which is decorated with nickel rings for magnetic actuation. Upon the application of rotating magnetic fields, the piezoelectric soft tail is deformed causing changes in its electric polarization. Capitalizing on this magnetically coupled piezoelectric effect, electrostatically enhanced on-demand release of therapeutic cargo loaded on the surface of the piezoelectric tail is demonstrated. It is also shown that this approach allows for a pulsatile release of payloads. Interestingly, the driving magnetic parameters can be selected to provide the nanoeel with translational motion or to control the discharge kinetics of the drug.
关键词： magnetic actuation,nanowires,drug delivery,piezoelectricity,soft robotics
更新于2025-09-19 17:15:36
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Bioinspired Stable and Photoluminescent Assemblies for Power Generation
摘要： Peptide assemblies are ideal components for eco-friendly optoelectronic energy harvesting devices due to their intrinsic biocompatibility, ease of fabrication, and flexible functionalization. However, to date, their practical applications have been limited due to the difficulty in obtaining stable, high-performance devices. Here, it is shown that the tryptophan-based simplest peptide cyclo-glycine-tryptophan (cyclo-GW) forms mechanically robust (elastic modulus up to 24.0 GPa) and thermally stable up to 370 °C monoclinic crystals, due to a supramolecular packing combining dense parallel β-sheet hydrogen bonding and herringbone edge-to-face aromatic interactions. The directional and extensive driving forces further confer unique optical properties, including aggregation-induced blue emission and unusual stable photoluminescence. Moreover, the crystals produce a high and sustained open-circuit voltage (1.2 V) due to a high piezoelectric coefficient of 14.1 pC N?1. These findings demonstrate the feasibility of utilizing self-assembling peptides for fabrication of biointegrated microdevices that combine high structural stability, tailored optoelectronics, and significant energy harvesting properties.
关键词： photoluminescence,cyclo-dipeptides,crystallization,mechanics,piezoelectricity
更新于2025-09-19 17:15:36
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Dielectric and piezoelectric augmentation in self-poled magnetic Fe <sub/>3</sub> O <sub/>4</sub> /poly(vinylidene fluoride) composite nanogenerators
摘要： One major discipline of contemporary research in energy harvesting and conversion aims in developing lead-free, biocompatible, easily scalable, flexible and high power-denisty composite piezoelectric films, which can obstruct electromagnetic interference also for smart device applications. A four-fold enhancement of its polar β-phase is verified from XRD and Raman spectra against incorporation of Fe3O4. Dielectric analysis suggests higher dielectric constant and lower dissipation for the films with tiny MNPs embedded in PVDF. The observations are duly validated from first principles studies. The physisorption process is recognized via geometrical optimization of Fe3O4/PVDF composite structure and significant amount of charge-transfer is demonstrated by the Mulliken charge-analysis. Open-circuit voltage and short-circuit current attain enhancement upto an order due to adequate ion-dipole and dipole-dipole interactions between the polar nanoscopic surface of Fe3O4 and PVDF. Finally, the nanogenerators are employed to light up commercial LEDs.
关键词： flexible nanogenerators,electret,electromagnetic interference shielding,superparamagnetic nanoparticles,Piezoelectricity
更新于2025-09-19 17:13:59
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20.1: <i>Invited Paper:</i> Monolithic Full‐color Quantum Dot Nanoring Micro LEDs with Improved Efficiency
摘要： BiMeO3 (where Me denotes a transition metal) is often used as a chemical modifier to form the Bi0.5Na0.5TiO3‐based solid solutions and to improve the electromechanical properties of the materials. In this study, BiMnO3 was selected as a chemical modifier, and (1 ? x)(0.94Bi0.5Na0.5TiO3‐0.06BaTiO3)–xBiMnO3 thin films with x = 0, 0.005, 0.01, and 0.015 were fabricated using the metal organic decomposition method to study the contributions of the third end‐member BiMnO3 to the reduction in the leakage current and the enhancement of the piezoelectric properties of Bi0.5Na0.5TiO3‐BaTiO3 thin films. Thin films with 1 mol% BiMnO3 exhibit a lower leakage current, and a better piezoelectricity and ferroelectricity, whose Smax/Emax, Pmax, 2Ec, and εr are 100.4 pm/V, 48.0 μC/cm2, 54.9 kV/cm, and 942, respectively.
关键词： metal organic decomposition,piezoelectricity,BNT–BKT–BMO thin films,leakage current
更新于2025-09-19 17:13:59
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Interfacing boron monophosphide with molybdenum disulphide for an ultrahigh performance in thermoelectrics, 2D excitonic solar cells and nanopiezotronics
摘要： Stable ultrathin 2D van der Waals (vdW) heterobilayer, based on the recently synthesized boron monophosphide (BP) and the widely studied molybdenum disulphide (MoS2), has been systematically explored for the conversion of waste heat, solar energy and nanomechanical energy into electricity. It shows a gigantic figure of merit (ZT) > 12 (4) for p (n)-type doping at 800 K, which is the highest ever reported till date. At room temperature (300 K), ZT reaches 1.1 (0.3) for p(n)-type doping which is comparable to experimentally measured ZT=1.1 on PbTe-PbSnS2 nanocomposite at 300 K. While it outweighs the Cu2Se-CuInSe2 nanocomposite (ZT=2.6 at 850 K) and the theoretically calculated ZT = 7 at 600 K on silver halides. Lattice thermal conductivity (???? ~ 49 Wm-1K-1) calculated at room temperature is lesser than that of black phosphorene (78 Wm-1K-1) and arsenene (61 Wm-1K-1). The nearly matched lattice constants in the commensurate lattices of the constituent monolayers helps to preserve the direct band gap at the K point in the type II vdW heterobilayer of MoS2/BP, where BP and MoS2 serve as donor and acceptor materials respectively. An ultrahigh carrier mobility ~ 20 × 103 cm2V-1s-1 is found, which exceeds that of previously reported transition metal dichalcogenide based vdW heterostructures. The exciton binding energy (0.5 eV) is close to that of MoS2 (0.54 eV) and C3N4 (0.33 eV) single layers. The calculated power conversion efficiency (PCE) in monolayer MoS2/BP heterobilayer exceeds 20%. It surpasses the efficiency in MoS2/p-Si heterojunction solar cells (5.23%) and competes with the theoretically calculated ones, listed in the manuscript. Furthermore, high optical absorbance (~105 cm-1) of visible light and small conduction band offset (0.13 eV) makes MoS2/BP very promising in 2D excitonic solar cells. Out-of-plane piezoelectric strain coefficient, ??33 ~ 3.16 pm/V, is found to be enhanced four-fold (~14.3 pm/V) upon applying 7% vertical compressive strain on the heterobilayer, which corresponds to ~1 kBar of hydrostatic pressure. Such a high out-of-plane piezoelectric coefficient, which can tune top-gating effects in ultrathin 2D nanopiezotronics, is a relatively new finding. As BP has been synthesized recently, experimental realization of the multifunctional, versatile MoS2/BP heterostructure would be highly feasible.
关键词： first-principles calculations,piezoelectricity,thermoelectricity,solar energy conversion efficiency,excitonic solar cells
更新于2025-09-12 10:27:22
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Structure and property of lead-free (K,Na)NbO3–(Bi1/2Na1/2)ZrO3–CaTiO3 piezoelectric ceramics
摘要： Simultaneous improvement of piezoelectricity and temperature stability is vital for developing high-performance KNN-based lead-free materials. Here, effects of CaTiO3 on phase structure, piezoelectricity and temperature stability of (1 – x)[0.95(K0.5Na0.5)NbO3–0.05(Bi0.5Na0.5)ZrO3]–xCaTiO3–0.2%MnO2 ceramics were studied. It was found that the orthorhombic-tetragonal phase transition temperature can be gradually decreased by increasing CaTiO3 content. Particularly, the improved strain temperature stability (strain varied < 15% when measurement temperature reaches 110 °C) and enhanced electrical properties (d33 ~ 296 pC/N and strain ~ 0.14%) can be observed in the ceramics with x = 0.02. Therefore, shifting the TO?T below room temperature is an effective way to promote temperature stability and electrical properties of KNN-based piezoelectric materials.
关键词： Lead-free piezoelectric ceramics,Temperature stability,CaTiO3,Piezoelectricity,KNN-based
更新于2025-09-10 09:29:36