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Lithium niobate (LiNbO 3 ) single crystals are a kind of ferroelectric material with a high piezoelectric coefficient and Curie temperature, which is suitable for the preparation of piezoelectric pressure sensors. However, there is little research reporting on the use of LiNbO 3 single crystals to prepare piezoelectric pressure sensors. Therefore, in this paper, LiNbO 3 was used to prepare piezoelectric pressure sensors to study the feasibility of using LiNbO 3 single crystals as a sensitive material for piezoelectric pressure sensors. In addition, chemical mechanical polishing (CMP) technology was used to prepare LiNbO 3 crystals with different thicknesses to study the influence of these LiNbO 3 crystals on the electric charge output of the sensors. The results showed that the sensitivity of a 300 μm sample (0.218 mV kPa -1 ) was about 1.23 times that of a 500 μm sample (0.160 mV kPa -1 ). Low-temperature polymer heterogeneous integration and oxygen plasma activation technologies were used to realize the heterogeneous integration of LiNbO 3 and silicon to prepare piezoelectric pressure sensors, which could significantly improve the sensitivity of the sensor by approximately 16.06 times (2.569 mV kPa -1 ) that of the original sample (0.160 mV kPa -1 ) due to an appropriate residual stress that did not shatter LiNbO 3 or silicon, thus providing a possible method for integrating piezoelectric pressure sensors and integrated circuits., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Antiferroelectric (AFE) films have received a lot of attention for their high energy storage density and temperature stability, giving them potential in electrostatic energy storage devices. In this work, La-doped PZT AFE films were prepared through a sol-gel procedure, and energy storage properties within a wide temperature range (73-533 K) were explored. Typical dipoles rotate in one direction along electric fields, combined with phase transition behavior. The polarization behavior is modulated by both electric field and temperature. With increasing temperature, the saturation polarization strength decreases due to the phase transition from the AFE state to the ferroelectric state. Besides, the temperature dependence of electrical properties was investigated, and the energy storage density of Pb 0.97 La 0.02 (Zr 0.95 Ti 0.05 )O 3 films was about 5.84 J/cm 3 in the low temperature range (<273.15 K). All results indicate the great potential of AFE films in pulse power device applications, especially in low-temperature ranges., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

The application of standing surface acoustic wave (SSAW) tweezers based on backpropagation superposition to achieve precise behavior manipulation of microscale cells and even nanoscale bacteria has been widely studied and industrialized. However, the structure requires multiple transducer components or full channel resonance. It is very challenging to design a simple structure for nano-control by complex acoustic field. In this study, a reflector-interdigital transducer (R-IDT) acoustofluidic device based on unilateral coherence enhancement is proposed to achieve SSAW definition features of periodic particle capture positions. The SAW device based on a unilateral transducer can not only generate leaky-SAW in water-filled microchannel, but also have a contribution of spherical waves in the vibration area of the substrate-liquid interface due to the Huygens-Fresnel diffractive principle. Both of them form a robust time-averaged spatial periodicity in the pressure potential gradient, accurately predicting the lateral spacing of these positions through acoustic patterning methods. Furthermore, a reflector based on Bragg-reflection is used to suppress backward transmitted SAW and enhance forward conducted SAW beams. By using a finite element model, R-IDT structure's amplitude enhances 60.78% compared to single IDT structure. The particle manipulation range of the diffractive acoustic field greatly improves, verified by experimental polystyrene microspheres. Besides, biocompatibility is conformed through red blood cells and Bacillus subtilis. We investigate the overall shift of periodic pressure field that can still occur when the phase changes. This work provides a simpler and low-cost solution for the application of acoustic tweezer in biological cell culture and filtering., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

Obtaining highly purified intact living cells from complex environments has been a challenge, such as the isolation of circulating tumor cells (CTCs) from blood. In this work, we demonstrated an acoustic-based ultra-compact device for cell sorting, with a chip size of less than 2 × 1.5 cm 2 . This single actuator device allows non-invasive and label-free isolation of living cells, offering greater flexibility and applicability. The device performance was optimized with different-sized polystyrene (PS) particles and blood cells spiked with cancer cells. Using the narrow-path travelling surface acoustic wave (np-TSAW), precise isolation of 10 μm particles from a complex mixture of particles (5, 10, 20 μm) and separation of 8 μm and 10 μm particles was achieved. The purified collection of 10 μm particles with high separation efficiency (98.75%) and high purity (98.1%) was achieved by optimizing the input voltage. Further, we investigated the isolation and purification of CTCs (MCF-7, human breast cancer cells) from blood cells with isolation efficiency exceeding 98% and purity reaching 93%. Viabilities of the CTCs harvested from target-outlet were all higher than 97% after culturing for 24, 48, and 72 h, showing good proliferation ability. This novel ultra-miniaturized microfluidic chip demonstrates the ability to sorting cells with high-purity and label-free, providing an attractive miniaturized system alternative to traditional sorting methods., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Graphene is an attractive material for terahertz (THz) absorbers because of its tunable Fermi-Level (E F ). It has become a research hotspot to modulate the E F of graphene and THz absorption of graphene. Here, a sandwich-structured single layer graphene (SLG)/ Polyimide (PI)/Au THz absorber was proposed, and top-layer graphene was doped by HAuCl 4 solutions. The E F of graphene was shifted by HAuCl 4 doping, which was characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and Raman tests. The results showed that the E F is shifted about 0.42 eV under 100 mM HAuCl 4 doping, the sheet resistance is reduced from 1065 Ω/sq (undoped) to 375 Ω/sq (100 mM). The corresponding absorbance was increased from 40% to 80% at 0.65 THz and increased from 50% to 90% at 2.0 THz under 100 mM HAuCl 4 doping. Detailed studies showed that the absorption came from a sandwich structure that meets the impedance matching requirements and provided a thin resonant cavity to capture the incident THz waves. In addition, not only the absorber can be prepared simply, but its results in experiments and simulations agree as well. The proposed device can be applied to electromagnetic shielding and imaging, and the proposed method can be applied to prepare other graphene-based devices.

Domain engineering plays a pivotal role in the development of ferroelectric non-volatile memory devices. In this work, we mainly focus on the domain kinetic in ion-sliced single crystal LiNbO 3 thin films under tip-induced electric fields using piezoresponse force microscope (PFM). Polarization reversal takes place when the electric fields are above threshold value (coercive voltage V c ) of films. Besides, the dependence of domain dynamic on pulse duration and amplitude were investigated in detail, and specific local domain reversal (5 μm) was completed by the optimized poling condition. All the results reveal that tip-induced polarization reversal could be an effective way to domain engineering, which gives much more promising prospects regarding to the high density non-volatile ferroelectric memory devices.

Antiferroelectric thin films are demonstrated as a new class of giant electrocaloric materials that exhibit a negative electrocaloric response of about -5 K near room temperature. The giant negative electrocaloric effect may open up a new paradigm for light, compact, reliable, and high-efficiency refrigeration devices., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)