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Surface acoustic wave (SAW) technology based on lithium niobate (LiNbO3) piezoelectric crystals has emerged as a powerful tool for investigating the mechanism of acoustoelectric interactions, relatively few attempts have focused on acoustophotoelectric research. Graphene has attracted extensive attention in the field of optical research due to its unique properties such as extremely high carrier mobility and broadband tunability. The LiNbO3/graphene coupling structure based on photoconductor-induced acoustic wave frequency shift is emerging as a novel approach to investigate the acoustophotoelectric response. In this study, we present a hybrid SAW-structure LiNbO3/graphene. Ultraviolet (UV) light is used as an effective strategy to control charge carrier changes in graphene, while the dynamic process is detected using the SAW technology. Results show that the sensitivity of the LiNbO3/graphene SAW device operating at 93 MHz is 4.09 ppm/(mW/cm2). Further, graphene was doped with HAuCl4 solution to enhance its photoelectronic properties, the sensitivity reaches 7.24 ppm/(mW/cm2). The UV sensitivity of the doped LiNbO3/graphene is 1.77 times higher than that of the undoped device. The incorporation of HAuCl4 into graphene leads to multitude effects that collectively enhance photoelectric performance, including modified Fermi-Level, increased charge carrier density. This device structure and research methodology provide significant technical and theoretical support for the development of graphene-based photoelectronic devices based on SAW technology. [ABSTRACT FROM AUTHOR]

Graphene-based metamaterials have been widely applied in optoelectronic devices, optical modulators, and chemical sensors due to the outstanding tunability and optical response in the terahertz (THz) region. Here, tunable THz metamaterial absorbers based on patterned graphene are designed, fabricated, and modulated. The proposed metamaterial absorbers are constructed by the top layer of patterned graphene arrays and the aluminum (Al) film separated by polyimide (PI). The different THz absorption spectra can be acquired by changing the patterns of graphene. In order to verify the simulation results, a series of tests were conducted by THz time-domain spectrometer (THz-TDS) systems. The proposed absorbers are able to be insensitive to the angle of the incident wave. Besides, chemical doping is applied to turn the Fermi level of graphene and the absorption performance is promoted with the increase of the Fermi level. The experimental results have been demonstrated to have associated resonant peaks with the simulation results. The aim of this paper is to exhibit a systematic study on graphene-based THz metamaterial absorbers, including the simulation and experiments. By comparing the simulation and experimental results, it is useful to clarify the relevant theories and manufacturing processes. The work will provide a further step in the development of high-performance terahertz devices, including tunable absorbers, sensors, and electro-optic switches. [ABSTRACT FROM AUTHOR]

High-performance infrared light sources have significantly influenced the fields of photonics and optoelectronics. However, achieving infrared light emission with low energy consumption, high brightness, and rapid response remains a huge challenge. Single-walled carbon nanotubes (SWCNTs) could be an important candidate for infrared light emitters because of their superior electron mobility and phonon transport efficiency. Here, we constructed a freestanding SWCNT emitter integrated into the PCB (printed circuit board) panel. The distinct one-dimensional (1D) subbands of SWCNTs that intersect at the Fermi energy significantly amplify electron-phonon scattering under a bias voltage. This enhancement results in outstanding infrared emission performance even in atmospheric environments. The infrared display device utilizing SWCNTs exhibits high radiation efficiency ( P i / P e ) of 2 × 10 -3 mW. This SWCNT achieves an infrared radiation temperature of up to 468 K at 1.5 V; the response time of the rising edge is 260 ms; and the falling edge is 360 ms, with an energy consumption P e of 0.45 W and an optical power P i of 9.02 mW. The device demonstrates stable display performance over 10 4 endurance cycles and can run persistently for more than 14 hours. This high thermal radiation, high-speed response efficiency, and low power consumption infrared emission from SWCNTs highlight their potential for future applications in infrared light sources.

Metformin (Met), a widely used type II diabetes medication, has shown anti-cancer properties in various cancers. RBMS3 is a tumor suppressor implicated in several cancers, including ovarian cancer. Ferroptosis, a novel form of programmed cell death, is gaining attention in cancer research. This study explores whether metformin induces ferroptosis and inhibits ovarian cancer progression through the RBMS3 pathway. We used a CCK-8 assay to determine the optimal metformin concentration for ovarian cancer cells. Metformin's effects were further evaluated using EdU assay and flow cytometry. To clarify its mechanism, we employed programmed cell death inhibitors and measured levels of MDA (Malondialdehyde), GSH (Glutathione), and Fe²⁺. Ferroptosis-related proteins and RBMS3 expression in ovarian cancer tissues and cells were assessed via RT-qPCR and Western blotting. A xenograft mouse model was used to observe metformin's effects on tumor growth. Metformin inhibited the viability of ovarian cancer A2780 cells, promoted ferroptosis, increased MDA and Fe²⁺ levels, and reduced GSH. It upregulated ferroptosis-related genes while downregulating GPX4 and SLC7A11. Although RBMS3 was reduced in cancer cells, metformin increased its expression, and silencing RBMS3 reversed metformin's effects. In vivo, metformin inhibited tumor growth, which was negated by RBMS3 silencing. Our findings suggest that metformin promotes ferroptosis and inhibits ovarian cancer progression by upregulating RBMS3, offering a promising direction for clinical application in ovarian cancer treatment., 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 © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

It is important to develop a wideband THz absorber for the prevention of terahertz electromagnetic pollution and information leakage. Some commonly used methods, such as metamaterials or dynamic modulation technology, have played important roles in the study of wideband THz absorbers. However, most of these absorbers are rigid or non-stretchable, which limits the practical applications in large mechanical deformation and non-plane scenarios. In the paper, we proposed a stretchable MWCNTs-OH/PDMS composite elastomer using the sugar template method. A series of characterization methods were carried out to verify the excellent compatibility of PDMS and MWCNTs-OH. Benefiting from its hierarchical porous structure, the draw-length ratio of sample and tensile strength reaches ∼ 190% and ∼ 0.4 MPa, respectively. More THz waves could be trapped inside the sample for conductive loss because of better impedance matching and conductivity loss (the smallest square value is ∼0.4 kΩ/□), which leads to wideband and high absorptivity (over 98% in 0.2∼2.0 THz range). Furthermore, the tested value of EMI SE was over 10 dB in 0.22∼1.82 THz frequency range at transmission mode. Combined with inherent hydrophobicity characteristics, the material also could be used in humid and rainy environments. The systemic study of stretchable MWCNTs-OH/PDMS composite elastomer will provide theoretical and technical support for subsequent THz absorption in practical scenarios.

Terahertz (THz) absorbers based on the Salisbury screen have attracted significant attention for high absorption performance and simple structure. Graphene is suitable for high-performance THz absorbers due to its extraordinary electronic and optical properties. The study of graphene THz absorbers based on Salisbury screens has attracted great interest, where the number of graphene layers significantly affects the interface impedance matching and absorption efficiency. In this work, we proposed a sandwich-structured graphene/Polyimide (PI) /Au THz absorber based on the Salisbury screen. The results show that the absorption peak tended to increase and then decrease with the increase in the number of graphene layers. The simulation demonstrates that the real and imaginary parts of the relative impedance of the 3-5 layer graphene absorber were 1.02 and 0.01, which achieved a better impedance matching with the free space. Meanwhile, the measured sheet resistance value of 426 Ω/sq was closest to the free-space impedance value of 377 Ω, consistent with the simulation results. The corresponding absorption reached a maximum value of 98.7% at 0.82 THz (measured). In addition, the absorption peak decreased from 98.7% to 86.7% as the angle of incidence increased from 0° to 60°. This demonstrates the advantage of wide-angle absorption. The proposed device is suitable for applications in electromagnetic shielding and imaging, while the suggested method can be employed for the fabrication of other graphene-based devices.

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.