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Due to oxidative damage and mitochondrial dysfunction, boar semen cryopreservation remains a significant challenge. This study investigates the effects of pyrroloquinoline quinone (PQQ), a mitochondrial-targeted antioxidant, on the post-thaw boar sperm quality during cryopreservation. Boar semen was diluted in a freezing extender containing different concentrations of PQQ (0, 10, 100, 1000, 10,000 nM). After freezing–thawing, the sperm motility, viability, acrosome integrity, mitochondrial activity, adenosine triphosphate (ATP) levels, DNA integrity, malondialdehyde (MDA) levels, reactive oxygen species (ROS) levels, superoxide dismutase (SOD) activity, mitochondrial transcription proteins levels, and fertilization capacity were assessed. The results show that 1000 nM PQQ supplementation to the freezing extender significantly enhanced post-thaw sperm motility, viability, and acrosome integrity compared to the control (p < 0.05). Additionally, 1000 nM PQQ increased mitochondrial membrane potential (MMP) and ATP levels, while decreasing MDA and mitochondrial ROS levels, and reducing DNA damage (p < 0.05). Furthermore, the levels of mitochondrial-encoded proteins were significantly elevated in the 1000 nM PQQ group compared to the control (p < 0.05). Interestingly, sperm in the 1000 nM PQQ group showed a higher binding rate to oviductal epithelial cells and the zona pellucida (ZP), indicating higher fertilization potential. These findings suggest that the use of mitochondria-target antioxidant, PQQ, can improve post-thaw boar sperm quality and fertilization via its capacity to reduce oxidative stress and protect mitochondrial function. [ABSTRACT FROM AUTHOR]

Exchange bias (EB) in antiferromagnetic (AFM)/ferromagnetic heterostructures is crucial for the advancement of spintronic devices and has attracted significant attention. The common EB effect in van der Waals heterostructures features a low blocking temperature (Tb) and a single polarity. In this work, a significant EB effect with a Tb up to 150 K is observed in FePS3/Fe3GaTe2 heterostructures, and in particular, the EB exhibits an unusual temperature‐dependent polarity‐reversal behavior. Under a high positive field‐cooling condition (e.g., μ0H ≥ 0.5 T), a negative EB field (HEB) is observed at low temperatures, and with increasing temperature, the HEB crosses zero at ≈20 K, subsequently becomes positive and later approaches zero again at Tb. A model composed of a top FePS3/interfacial FePS3/Fe3GaTe2 sandwich structure is proposed. The charge transfer from Fe3GaTe2 to FePS3 at the interface induces net magnetic moments (∆M) in FePS3. The interface favors AFM coupling, and thus the reversal of ∆M of the interfacial FePS3 leads to the polarity‐reversal of EB. Moreover, the EB can be extended to the bare Fe3GaTe2 region of the Fe3GaTe2 flake partially covered by FePS3. This work provides opportunities for a deeper understanding of the EB effect and opens a new route toward constructing novel spintronic devices. [ABSTRACT FROM AUTHOR]

Mid‐infrared (MIR) lasers generated by nonlinear optical (NLO) crystals have aroused extensive attention in various military and civilian applications. Among the MIR NLO crystal family, LiInSe2 (LISe) is a promising candidate in the generation of MIR lasers due to its wide transmission range, large bandgap, and high laser‐induced damage threshold. However, the intrinsic defects in LISe induce optical losses, which will induce laser damage and hinder the performance of MIR laser generation. In this work, the mechanism of optical absorption induced by defects is revealed in LISe through transient absorption (TA) spectroscopy. It is verified that the deep‐level defects in LISe give rise to the extra optical absorption, which is owing to the excited state absorption (ESA) and photo‐induced absorption (PIA). Accordingly, for improving the optical properties of LISe crystals, Li2Se vapor‐mediated annealing to reduce defects concentration is rationally designed. The results confirmed that the optical properties of annealed LISe are improved due to the decrease of defects concentration. Ultimately, the performance of MIR laser generation is successfully enhanced by using the annealed LISe crystal. This work provides deep insights into the defect‐induced absorption losses in LISe crystals and promotes the application of LISe crystals in MIR laser generation. [ABSTRACT FROM AUTHOR]

The LD conversion offers great potential in providing an additional degree of freedom that may be beneficial to novel polarization‐wavelength‐selective detectors and optical switching. However, conventional crystals with optical anisotropy typically show unidirectional LD over a broad wavelength range and the materials with LD conversion behavior remain scarce. Here, by combining angle‐resolved polarized optical absorption measurements and theoretical calculations, this study demonstrates that quasi‐1D Weyl semimetal (TaSe4)2I single crystal shows unique LD conversion phenomenon at the wavelength of 1064 nm. Meanwhile, (TaSe4)2I persists giant linear optical anisotropy due to the intrinsic feature of 1D [TaSe4] chains along the c‐axis. Additionally, the (TaSe4)2I nanoribbon exhibits anisotropic second harmonic generation (SHG). These results hold significant importance to facilitate the development of topological photonics and novel photonic devices applications based on topological semimetals. [ABSTRACT FROM AUTHOR]

Simple Summary: Boar sperm is a highly sensitive biological product, and its quality is susceptible to various environmental factors during transportation. Presently, vibration emissions were observed and documented during the transportation of artificial insemination doses. Vibrations, serving as an environmental stressor, harbor the potential to exert an influence on sperm quality. However, the precise mechanism underlying the detrimental effects of vibration emissions on sperm functionality remains elusive. In the present research, we discerned that vibration emissions impair the quality of boar sperm by modulating their metabolic processes, ultimately resulting in a diminished fertilization capability. Artificial insemination (AI) with liquid-preserved semen has recently become common in pig breeding. The semen doses are produced in a centralized manner at the boar stud and then subsequently distributed and transported to sow farms. However, vibration emissions during transportation by logistic vehicles may adversely affect the quality of boar sperm. Therefore, this study aimed to explore the impact of vibration-induced emissions on sperm quality and function under simulated transportation conditions. Each time, ejaculates from all 15 boars were collected and then pooled together to minimize individual variations, and the sample was split using an extender for dilution. Different rotational speeds (0 rpm, 80 rpm, 140 rpm, 200 rpm) were utilized to simulate varying intensities of vibration exposure using an orbital shaker, considering different transportation times (0 h, 3 h, and 6 h). Subsequently, evaluations were conducted regarding sperm motility, plasma membrane integrity, acrosome integrity, mitochondrial function, adenosine triphosphate (ATP) levels, mitochondrial reactive oxygen species (ROS) levels, pH, glycolytic pathway enzyme activities, and capacitation following exposure to vibration emissions. Both vibration time and intensity impact sperm motility, plasma membrane integrity, and acrosomal integrity. Vibration exposure significantly reduced sperm ATP levels, mitochondrial membrane potential, and the levels of mitochondria-encoded proteins (MT-ND1, MT-ND6) (p < 0.05). After vibration emission treatment, the pH value and mitochondrial ROS levels significantly increased (p < 0.05). Inhibition of sperm glycolysis was observed, with reduced activities of hexokinase (HK), pyruvate kinase (PK), and lactate dehydrogenase (LDH), along with decreased lactate levels (p < 0.05). Additionally, sperm tyrosine phosphorylation levels were significantly reduced by vibration emissions compared to the control group (p < 0.05). After the vibration emission treatment, the number of sperm bound to each square millimeter of oviduct explants decreased significantly compared to the control group (p < 0.05). Similarly, compared to the control group, using semen subjected to vibration stress for AI results in significantly reduced pregnancy rates, total born litter size, live-born litter size, and healthy born litter size (p < 0.05). [ABSTRACT FROM AUTHOR]

Two-dimensional semiconductors, such as MoS2, have demonstrated great potential applications in post-Moore electronic and optoelectronic devices, and organic cations intercalation has been widely utilized to modulate their physical properties. However, the correlation between the conductivity, carrier mobility, carrier density, and structure of organic cations intercalated MoS2 is still unclear. In this Letter, we systematically investigated the structural and electrical transport properties of pristine MoS2 and MoS2 intercalated with various organic cations such as tetradecyltrimethyl-ammonium, tetraheptyl-ammonium, and cetyltrimethyl-ammonium. Semimetal bismuth (Bi) was used as electrodes to make Ohmic contact with MoS2, and four-probe measurements were employed to obtain the intrinsic conductivity of MoS2. The intercalated organic cations greatly expand interlayer spacing and strongly dope MoS2 up to an electron concentration of 6.1 × 1013 cm−2 depending on the size and intercalation amount of organic cations. The severe electron doping constrains the out-of-plane A 1 g vibration mode and screens the Coulomb scattering, such that the intercalated MoS2 has enhanced Hall mobility of >50 cm2 V−1 s−1 at room temperature and even >1700 cm2 V−1 s−1 at 5 K. The intercalated MoS2 responds much faster than pristine MoS2 when functioning as a phototransistor. Our work provides insight for understanding the electrical transport properties of MoS2 and designing more efficient electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Single crystals of the perovskite nickelate NdNiO3 with dimensions of up to 50 μm on edge have been successfully grown using the flux method at a temperature of 400 °C and oxygen pressure of 200 bar. The crystals were investigated by a combination of techniques, including high-resolution synchrotron X-ray single-crystal and powder diffraction and physical property measurements such as magnetic susceptibility and resistivity. Resistivity measurements revealed a metal-insulator transition (MIT) at TMIT~180 K with apparent thermal hysteresis; however, no superlattice peaks or peak splitting below TMIT, which corresponds to a structural transition from Pbnm to P21/n, was observed. The successful growth of NdNiO3 crystals at relatively low temperatures and oxygen pressure provides an alternative approach for preparing single crystals of interesting perovskites such as RNiO3 (R = Sm-Lu) and parent phases of superconducting square planar nickelates. [ABSTRACT FROM AUTHOR]

To electrically control magnetic properties of material is promising toward spintronic applications, where the investigation of carrier doping effects on antiferromagnetic (AFM) materials remains challenging due to their zero net magnetization. In this work, the authors find electron doping dependent variation of magnetic orders of a 2D AFM insulator NiPS3, where doping concentration is tuned by intercalating various organic cations into the van der Waals gaps of NiPS3 without introduction of defects and impurity phases. The doped NiPS3 shows an AFM‐ferrimagnetic (FIM) transition at a doping level of 0.2–0.5 electrons/cell and a FIM‐AFM transition at a doping level of ≥0.6 electrons/cell. The authors propose that the found phenomenon is due to competition between Stoner exchange dominated inter‐chain ferromagnetic order and super‐exchange dominated AFM order at different doping level. The studies provide a viable way to exploit correlation between electronic structures and magnetic properties of 2D magnetic materials for realization of magnetoelectric effect. [ABSTRACT FROM AUTHOR]

The ocean-going environment is complex and changeable with great uncertainty, which poses a huge challenge to the navigation ability of ships working in the pelagic ocean. In this paper, in an attempt to deal with the complex uncertain interference that the environment may bring to the strap-down inertial navigation system/polarization navigation system/geomagnetic navigation system (SINS/PNS/GMNS) integrated navigation system, the multi-mode switching variational Bayesian adaptive Kalman filter (MMS-VBAKF) algorithm is proposed. To be more specific, to identify the degrees of measurement interference more effectively, we design an interference evaluation and multi-mode switching mechanism using the original polarization information and geomagnetic information. Through this mechanism, the interference to the SINS/PNS/GMNS navigation system is divided into three cases. In case of slight interference (case SI), the variational Bayesian method is adopted directly to solve the problem that the statistical characteristics of measurement noise are unknown. By the fixed-point iteration mechanism, the statistical properties of the measurement noise and the system states can be estimated adaptively in real time. In case of interference-tolerance (case TI), the estimation of the statistical characteristics of measurement noise need to weigh the measurement information at the moment and a priori value information comprehensively. In case of excessive interference (case EI), the SINS/PNS/GMNS integrated navigation system will perform mode switching and filtering system reconstruction in advance. Then, the information fusion and navigation states estimation can be completed. Consequently, the reliability, robustness, and accuracy of the SINS/PNS/GMNS integrated navigation system can be guaranteed. Finally, the effectiveness of the algorithm is illustrated by the simulation experiments. [ABSTRACT FROM AUTHOR]

Bionic navigation is an essential technology in GPS-denied environment for vehicle navigation. This paper combined strapdown inertial navigation system, polarized skylight sensors and odometer to design a new navigation model. In particular, a novel measurement model is developed based on polarized skylight. This model primarily utilizes the cross product to compute the error between the measured polarization vector and the theoretical polarization vector. It differs from the error computed by strapdown inertial navigation system in design vector measurement model. It deals with the problem of the directional ambiguity of polarization vector difference directly. Considering the measured polarization vector error due to computation and multiple scattering from atmospheric molecules, the states are augmented with the measured vector error to form a partially nonlinear, bionic integrated navigation model. To reduce the computation burden, marginalised unscented Kalman filter is presented to estimate the unknown states. The observability analysis method of piece-wise constant systems is applied to compute the observability matrix and singular value. Simulation results show that linear maneuver and angular maneuver can improve the degree of the observability of attitude and measured polarized vector error. Finally, experiments further verify the effectiveness of proposed models and method. [ABSTRACT FROM AUTHOR]

Terahertz (THz) technology has attracted great attention in the past few decades for its unique applications in various fields, including spectroscopy, noninvasive detection, wireless communications, and imaging. In parallel to this, the practical, fast, and broadband modulation of THz waves is becoming indispensable. Two‐dimensional (2D) materials exhibit unusual optical and electrical properties, which has prompted tremendous interest and significant advances in THz modulation. This review provides the recent progress in 2D materials‐based THz modulators, outlining the operating principles, including all‐optical, electro‐optic, magneto‐optic, and other exotic mechanisms. We focus on the recent advances in THz modulation by the designed photonic structures, such as heterostructure, metamaterial, capacitor, optical cavity, and waveguide integration. Lastly, we discussed the challenges and opportunities for 2D materials‐based THz modulators and presented our prospects for the future development. [ABSTRACT FROM AUTHOR]

The in‐plane anisotropic feature of 2D layered materials has captured enormous research interest due to their application in polarization‐sensitive photodetection. Here, silicon phosphide (SiP), as a novel member of group IV–V 2D materials, is first introduced to the anisotropic 2D materials family with a high in‐plane anisotropy. The low‐symmetry structure, optical and optoelectronic properties are investigated systematically. Impressively, the photodetectors based on 2D SiP demonstrate high performance with low dark current, a fast response speed of 30 µs, and a strong anisotropic photoresponse with an anisotropic factor of 2.9. Furthermore, a strong polarization‐sensitive photodetector with a dichroic ratio up to 2.3 is realized based on the intrinsic linear dichroism of 2D SiP. This work not only provides an insight into the in‐plane anisotropic properties of 2D SiP, but also sheds light on its great potentials in anisotropic optoelectronic applications. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2) is one of the two-dimensional layered semiconductor transition metal dichalcogenides (TMDCs) with great potential in electronics, optoelectronics, and spintronic devices. Sulfur vacancies in MoS2 are the most prevalent defects. However, the effect of sulfur vacancies on the electronic structure of MoS2 is still in dispute. Here we experimentally and theoretically investigated the effect of sulfur vacancies in MoS2. The vacancies were intentionally introduced by thermal annealing of MoS2 crystals in a vacuum environment. Angle-resolved photoemission spectroscopy (ARPES) was used directly to observe the electronic structure of the MoS2 single crystals. The experimental result distinctly revealed the appearance of an occupied defect state just above the valence band maximum (VBM) and an upward shift of the VBM after creating sulfur vacancies. In addition, density functional theory (DFT) calculations also confirmed the existence of the occupied defect state close to the VBM as well as two deep unoccupied states induced by the sulfur vacancies. Our results provide evidence to contradict that sulfur vacancies indicate the origin of n-type behaviour in MoS2. This work provides a rational strategy for tuning the electronic structures of MoS2. [ABSTRACT FROM AUTHOR]

Despite the impressive progresses in terahertz (THz) sources and detection, there is still a big challenge for high performance active optoelectronic THz devices such as THz modulators. All‐optically controlled THz modulators with large modulation depth (MD) and wide modulation bandwidth are of great importance for the THz technology. Herein, a MoTe2/Si van der Waals (vdWs) heterostructure is rationally designed as all‐optical THz modulator by taking advantage of their similar band alignment and easy integration with Si complementary metal‐oxide‐semiconductor (CMOS). The MoTe2/Si modulator presents an ultrasensitive THz modulation performance with a MD of 99.9% under a low illumination power of 300 mW at 1064 nm. This is a record MD for TMDCs‐based all‐optically controlled THz modulators to date. Moreover, the MoTe2/Si modulator exhibits broadband modulation performance with a wide frequency range from 0.3 to 2.0 THz. The high modulation performance under low illumination power is beneficial for practical application with low energy consumption and easy heat dissipation, which is advantageous to modulator chip. This work validates a facile protocol for fabricating high performance THz modulators and paves the way for their practical applications in THz technology. [ABSTRACT FROM AUTHOR]

Contact engineering, especially at the interface between metal and 2D semiconductors, to enable high‐performance devices remains a formidable challenge due to the inevitable chemical disorder and Fermi‐level pinning at the interface. Here, the authors report the InSe–Se vertical van der Waals (vdW) heterostructures to achieve high field‐effect mobility and electrical stability in 30 nm InSe field‐effect transistor (FET), which has a low lattice mismatch of 1.1% and form 2D/2D low‐resistance contacts, creating an InSe contact interface that substantially limits chemical disorder and Fermi‐level pinning. The Se layer forms a vdW contact to prevent the damage induced by direct metallization and acts as a tunneling layer as well as a protective encapsulation layer. Using this approach, heterojunction devices with a high field‐effect mobility of ≈2500 cm2 (V s)−1 and an excellent on‐state current of ≈10−3 A at room temperature is achieved. Furthermore, the device field‐effect mobility degrades by only 3.46% following two months of storage time in open air, which represents the best electrical stability reported to date. In particular, the heterojunction devices exhibit a better photoresponsivity compared with InSe devices in practical application. This study provides a highly valuable strategy to improve the contact condition of metal/2D semiconductors for high‐performance, 2D‐based electronics and optoelectronics. [ABSTRACT FROM AUTHOR]

A novel autonomous initial alignment for the stationary strapdown inertial navigation system (SINS) with the bio-inspired polarized skylight sensors (PSS) is proposed to improve the precision and convergence speed in this paper. A pair of perpendicularly polarized skylight sensors with six-channels are used to measure and calculate the polarization azimuth angles, which is finally constructed a new polarized measurement error equation. With the SINS error equations, the SINS/PSS integrated navigation error equations are developed to achieve autonomous and fast initial alignment. Two types of observability, geometric observability and stochastic observability, are introduced to evaluate the integrated navigation systems. The geometric observability, which is defined by calculating the rank of the observability matrix, is analysed. It is found that the integrated navigation systems are not completely observable. Further, the degree of observability based on singular value decomposition is also used to examine the observable degree of the SINS/PSS integrated navigation system. The stochastic observability is associated with observability analysis with the estimated precision of the designed filter. The Kalman filter is designed to estimate the unknown state based on the measurements from the inertial measurement unit and PSS. Simulations and experiments demonstrate that the SINS/PSS achieve a rapid initial alignment with higher precision. Compared with the SINS, the vertical misalignment angle accuracy of SINS/PSS is improved by more than 90%, and the time cost is shortened by 60% in the simulation test. For the initial alignment experiment, the vertical misalignment greatly improved the accuracy and shorten the time cost. [ABSTRACT FROM AUTHOR]

The second order nonlinear optical properties of BaTeMo2O9 were studied by means of Maker fringe technology and the phase matching method. The value and relative sign of the second order nonlinear optical coefficients were obtained, with the largest being d31 = 9.88 pm/V. At 1064 nm, the crystal can support noncritical phase-matching, and the effective nonlinear coefficient is 10.3 pm/V for phase matching II at (90°, 62.8°) in the x0y plane. The relation between the second order nonlinear properties and the crystal structure is also discussed. All the results show that BaTeMo2O9 is a good candidate for nonlinear optical applications. [ABSTRACT FROM AUTHOR]

In this work, single-crystal BiFeO3/PbTiO3 (BFO/PTO) nanoplates have been successfully synthesized via a hydrothermal method. It is interesting to find that BFO films selectively grew on the negative polar surface of PTO nanoplates with a saturation thickness of about 18–20 nm. Below such saturation size, the thickness of BFO films can be controlled in the range of 4–18 nm. An atomically sharp interface was identified to be formed between BFO and PTO with an epitaxial relationship of {012}BFO//{001}PTO. In particular, a room-temperature ferromagnetism in the nanoplates has been observed, where the saturation magnetization significantly decreased from to 0.029 to 0.003 emu g−1 upon the film thickness decreasing to 4 nm. Electron energy-loss spectroscopy (EELS) analysis on the interface suggests that the positive polar surface of BFO could be screened by both of the negative polarization and addition electrons in PTO. A mechanism of "screening balance broken and rebuilt" on the negative interface was proposed to explain the existence of selective growth, the saturation thickness and magnetism of the nanoplates. The findings suggest that a polar surface could be a powerful platform to realize the controllable epitaxial growth of perovskite oxide heterostructures with the intriguing interface functionality. [ABSTRACT FROM AUTHOR]

Purpose: Multiple-source disturbances exist in the polarization sensor, which severely affect the sensor accuracy and stability. Hence, the disturbance analysis plays a vital role in improving the sensor orientation performance. This paper aims to present a novel sensor error model, a disturbances quantitative analysis, a calibration and performance test of polarization sensor based on a polarizing beam splitter. Design/methodology/approach: By combining with the sensor coefficient errors, the Azimuth of Polarization (AoP) error model and the Degree of Polarization (DoP) error model are established, respectively. In addition, the multiple-source disturbances are classified, while the influence on the orientation accuracy is quantitative analyzed. Moreover, the least square optimization algorithm is employed to calibrate the sensor coefficients. Finally, an outdoor test is carried out to test the sensor long-term accuracy. Findings: The theoretical analysis and numerical simulations illustrate that the sensor accuracy is closely related to the disturbances. To eliminate the influence of the disturbances, the least square optimization algorithm, which can minimize the sum of squares of the residual difference of AoP and DoP, is used to calibrate the sensor coefficients. The outdoor test indicates that the sensor can maintain long-term accuracy and stability. Originality/value: The main contribution of this paper is to establish a novel sensor error model, where the sensor coefficient errors are introduced. In addition, the disturbances are classified and analyzed to evaluate the orientation accuracy of the sensor. [ABSTRACT FROM AUTHOR]

High quality and large size nonlinear optical LiInS2 (LIS) crystals were successfully grown by the optimized seeded Bridgman method. And the optical properties and carrier dynamics of LIS in the THz range were investigated by THz time-domain spectroscopy (THz-TDS) in the temperature range of 20–300 K for the first time. The refractive index and absorption coefficients present obvious temperature dependent behavior. A distinct absorption peak was observed at around 1.68 THz, which can be attributed to the vibration of In–S bonds revealed by Raman spectroscopy analysis. And the carrier concentration, mobility and scattering rate also show obvious temperature dependent behavior. These results will provide further understanding of the optical properties of LIS crystals and a perspective for future applications of LIS crystals in THz technology. [ABSTRACT FROM AUTHOR]

Mid-infrared (MIR) coherent light generated by nonlinear optical (NLO) materials is crucial for military and civilian applications. Among the MIR optical crystal family, the LiInSe2 (LISe) single crystal is a promising candidate due to its remarkable physical properties. Herein, a high-quality LISe crystal with the largest diameter of 31 mm was successfully grown by the Bridgman growth method using an oriented seed. The crystalline quality and optical homogeneity of LISe were demonstrated by high-resolution X-ray diffraction (HRXRD), Laue diffraction, and optical interferometry measurements, respectively. Additionally, a complete survey of the transmittance spectra, absorption coefficients, and refractive indices was systematically performed. Furthermore, we found that the absorption coefficients of LISe at 1.064 μm can be obviously decreased after thermal annealing under LISe atmospheric conditions. More generally, our results will contribute significantly to the practical applications of LISe in the MIR technology field. [ABSTRACT FROM AUTHOR]

As an environmentally friendly and chemically robust crystal, LiInSe2 (LISe) exhibits promising optoelectronic properties. Here, an ultrasensitive metal–semiconductor–metal (MSM) structured photodetector based on a high-quality LISe crystal was systemically investigated. Remarkably, the LISe based photodetectors exhibit an outstanding photosensitivity with a high on/off current ratio (6.80 × 104), fast photoresponse (trise = 180 μs and tdecay = 200 μs), and high detectivity (2.16 × 1012 Jones). This work may lay the foundation and ignite future research interest on chalcogenide crystals in photodetectors. [ABSTRACT FROM AUTHOR]

Group IV–V 2D semiconductors, such as GeP and GeAs, have attracted increasing attention as a hot research topic due to their high in-plane anisotropic properties. As one among them, orthorhombic SiP (o-SiP) deserves more attention due to its sufficiently high carrier mobility, large band gap, excellent stability and even a direct band gap in the monolayer. In this work, the experimental Raman modes were identified based on DFT calculations and then we demonstrated highly in-plane anisotropy of the phonon vibrations by angle-resolved polarized Raman spectroscopy. In addition, o-SiP based photodetectors were fabricated to investigate the in-plane anisotropic photoresponse. The results indicate that o-SiP is an alternative photodetector with high responsivity and well-reproducible cycles. Furthermore, high anisotropy was revealed with a notably anisotropic on/off switching ratio. Our results show that o-SiP is a new member of the family of group IV–V 2D semiconductors with intriguing optoelectronic properties, and will open new opportunities for promising applications in advanced photonic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

TiO2/carbon fiber composite is achieved by loading TiO2 nanoparticles on biomass carbon fiber, which originates from the carbonized natural bast. The carbonized process and the loading amount of TiO2 are researched in detail. It is found that the carbonized bast fiber shows robust adsorption characteristics for TiO2 nanoparticles in aqueous dispersion, and TiO2 nanoparticles with ~15 wt.% in total weight are uniformly loaded onto the fiber surface. The photocatalytic properties of TiO2/carbon fiber composite are evaluated by photocatalytic degradation of rhodamine B and water splitting for hydrogen production. The results indicate that 90% RhB molecules could be attacked in 60 min under UV light irradiation, and the hydrogen production rate of water splitting is up to 338.51 μmol/h. The highlight is that TiO2/carbon fiber composite is easy to be recycled due to the incorporation of macroscopical biomass carbon fiber. [ABSTRACT FROM AUTHOR]

Abstract: The development of low‐cost and highly reactive electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in basic media is still a great challenge. Herein, we design a three‐dimensional Co3O4@NiFe‐LDH (LDH: layered double hydroxide) core‐shell nanostructure on Ni foam, in which the core Co3O4 nanowires play a key role in the stability and the shell NiFe‐LDH nanosheets provide the main active sites for electrocatalytic water splitting. The as‐prepared Co3O4@NiFe‐LDH exhibits excellent electrocatalytic activity for OER with a low overpotential of 269 mV at a current density of 100 mA cm−2, a small Tafel slope of 66 mV dec−1, and excellent stability without degradation over 40 h. Furthermore, the sample also demonstrates robust performance for HER with a low overpotential of 74 mV at a current density of 10 mA cm−2. Most importantly, when employing the Co3O4@NiFe‐LDH/NF as both anode and cathode, only 1.56 V is needed to achieve a current density of 10 mA cm−2, which is lower than the combination of Pt/C and IrO2 catalysts for overall water splitting. This work provides a significant strategy toward the rational design of novel core‐shell electrocatalysts for overall water splitting. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials have recently attracted great interest due to their promising optoelectronic applications. Orthorhombic SiP (o-SiP) is a 2D layered crystal and may have a significant impact on optoelectronic technologies. Large-sized bulk o-SiP single crystals have been successfully grown by a seeded flux method. The size and morphology of o-SiP crystals can be controlled by changing the growth conditions. The carrier mobility and band gap of o-SiP were characterized in detail. The photoresponse properties of o-SiP were investigated and a relatively fast response has been demonstrated. The experimental results indicate that o-SiP may be an excellent candidate for applications in electronics and optoelectronics. [ABSTRACT FROM AUTHOR]

In view of their high nonlinear optical coefficients and good phase-matching properties, CdSiP2 (CSP) crystals are considered as one of the most promising materials in the field of nonlinear optical applications. However, the slight absorption losses around 1.34 μm and 1.78 μm under e-polarized light have been affecting its performance. In this study, first-principles calculations were performed to identify the effects of various charge defects on the absorption properties. Different intrinsic defects in the CSP crystal were calculated using the HSE method and compared according to the specific chemical environments in the experiments. The results show that the point defects of V2−Cd, Si2+Cd, and V4−Si, which can be spontaneously formed, are dominant in the Cd-poor environment. The combination of Si2+Cd and V2−Cd defects is the most favorable cluster in the Cd-poor case because of its relatively low formation energy. Furthermore, the antisite defect SiCd was found to be responsible for the main absorption peaks at 1.34 and 1.78 μm in the experimental spectra, whereas other defects and clusters, such as the defects Si2+Cd and V0Si, also contribute to these red shifted absorptions. Our results intend to provide a guideline for adjusting the optical absorption in CSP by modifying its defects. [ABSTRACT FROM AUTHOR]

CaGdAlO4 (CGA) single crystals have been grown in different oxygen concentration atmospheres by the Czochralski method. Crystals grown under an oxygen-containing atmosphere presented an inconsistent brown coloration. The origin of coloration was studied by density functional theory, and the simulated results show the oxygen defects and the absorption matched well with the experimental results. The brown coloration of CGA is due to the interstitial oxygen atoms. The fundamental properties of CGA crystals with different colors, including the crystal density, hardness, thermal and optical properties, were systematically investigated and compared when taking into account the effect of color center inside. The colorless CGA was grown under an inert gas atmosphere and exhibits a wide transparency range of 227–7140 nm. The maximum phonon energy was determined to be as low as 618 cm−1. The colorless CGA host crystal with a disordered structure, good thermal conductivity, low maximum phonon energy and wide transparency is promising for ultrafast ultraviolet and visible laser applications. [ABSTRACT FROM AUTHOR]

Single crystals of Bi2Mo2.66W0.34O12 with dimensions up to 70 mm × 55 mm × 45 mm were successfully grown using a top-seeded solution growth (TSSG) method with a MoO3–WO3 mixture as a flux. The material crystallizes in centrosymmetric space group P21/c (no. 14), with unit cell parameters of a = 7.7212(8) Å, b = 11.4938(12) Å, c = 11.9970(12) Å, and β = 115.5070(10)°. The as-grown crystals exhibit {100}, {010}, {011}, {110}, {021}, {012}, {120}, {−111}, {−102}, and {1−1−2} facets, which are in good agreement with the predicted growth morphology based on the Bravais–Friedel and Donnay–Harker (BFDH) method. High-resolution X-ray diffraction (HRXRD) measurement on the (040)-faced plate shows that the full-width at half-maximum (FWHM) of the rocking curve is 54′′, which indicates high crystal quality. Our measurements show that it melts congruently and exhibits a wide transmission range from 475 nm to 5200 nm. It is worth noting that Bi2Mo2.66W0.34O12 has a large birefringence (Δn = 0.24 at 480 nm), indicating that the crystal can be a promising polarizing optical material. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2) has attracted a great deal of attention because of its outstanding physical, chemical and optoelectronic properties. The method used to prepare large sized MoS2 crystals of very high quality is still an important issue for determining the feasibility of its application. Herein, we propose a novel Sn flux method to grow single crystal MoS2, and bulk MoS2 single crystals with a size of 3 mm × 5 mm were successfully obtained by using a cooling rate of 2–4 °C h−1. The growth mechanism of the MoS2 crystal in Sn flux was investigated in detail using optical microscopy and atomic force microscopy (AFM). The obvious screw dislocation steps that are revealed suggest that the growth of MoS2 is controlled by a screw-dislocation-driven (SDD) spiral growth mechanism. The flux-grown MoS2 crystals were exfoliated to produce high-quality large-scale films using the liquid-phase exfoliation method. Using ultrathin MoS2 films as a saturable absorber, a passively Q-switched laser at a wavelength of 1.06 μm was constructed and operated, with a narrow pulse width of 326 ns. [ABSTRACT FROM AUTHOR]

THz modulators based on 2D materials are attracting attention due to their potential applications in THz communication, sensing, and biomedical diagnostics. The authors present recent progress on 2D materials with different photonic structures, fundamental of THz modulation, and THz operation principles. This work provides useful guidance for the design strategy of 2D materials based THz modulators. (DOI: 10.1002/inf2.12236) [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials driven by their unique electronic and optoelectronic properties have opened up possibilities for their various applications. The large and high-quality single crystals are essential to fabricate high-performance 2D devices for practical applications. Herein, IV-V 2D GeP single crystals with high-quality and large size of 20 × 15 × 5 mm3 were successfully grown by the Bi flux growth method. The crystalline quality of GeP was confirmed by high-resolution X-ray diffraction (HRXRD), Laue diffraction, electron probe microanalysis (EPMA) and Raman spectroscopy. Additionally, intrinsic anisotropic optical properties were investigated by angle-resolved polarized Raman spectroscopy (ARPRS) and transmission spectra in detail. Furthermore, we fabricated high-performance photodetectors based on GeP, presenting a relatively large photocurrent over 3 mA. More generally, our results will significantly contribute the GeP crystal to the wide optoelectronic applications. [ABSTRACT FROM AUTHOR]

In this paper, to address the problem of positioning accumulative errors of the inertial navigation system (INS), a bionic autonomous positioning mechanism integrating INS with a bioinspired polarization compass is proposed. In addition, the bioinspired positioning system hardware and the integration model are also presented. Concerned with the technical issue of the accuracy and environmental adaptability of the integrated positioning system, the sun elevation calculating method based on the degree of polarization (DoP) and direction of polarization (E-vector) is presented. Moreover, to compensate for the latitude and longitude errors of INS, the bioinspired positioning system model combining the polarization compass and INS is established. Finally, the positioning performance of the proposed bioinspired positioning system model was validated via outdoor experiments. The results indicate that the proposed system can compensate for the position errors of INS with satisfactory performance. [ABSTRACT FROM AUTHOR]

Investigating celestial polarization patterns in the case of different environments is important for exploring the atmospheric radiative transfer mechanism. Although intensive studies on clear sky, foggy sky, and even total solar eclipse sky have been conducted, the polarization distribution generated by the moonlight has not been well investigated. This study analyzes celestial polarization patterns generated by the Super Blue Blood Moon (SBBM) through several comparative studies. The polarization patterns under the SBBM are collected, analyzed, and compared with both those generated by the ideal single-scattering Rayleigh model and those in the normal sky. From the analysis of the relative variation of the celestial polarization characteristics including the Degree of Polarization (DoP) and Angle of Polarization (AoP), the changes of the extremum, frequency, symmetric line, and neutral points are discussed. As a result, SBBM polarization patterns change at the beginning of the partial eclipse, and the neutral points vary from traditional neutral points. The value of DoP gradually decreases as the obscuration ratio of the Moon increases. The AoP is no longer symmetrical about the celestial meridian. As a conclusion, it is suggested that the variation of the polarized skylight during the SBBM should be considered in atmospheric model calculation for nocturnal biological activity and navigation information computation. [ABSTRACT FROM AUTHOR]

Germanium phosphide (GeP), a typical 2D group IV–V semiconductor, has attracted significant attention due to the advantages of higher thermodynamic stability than black phosphorus (BP), widely tunable bandgap, high carrier mobility, and in‐plane anisotropy. However, its photonic and optoelectronic properties have not been extensively explored so far. Herein, large size and high‐quality GeP single bulk crystal is successfully grown by flux method and stripped into 2D nanosheets with liquid phase exfoliation (LPE) and spin‐coating methods. The broad‐band photonic and optoelectronic properties of 2D GeP nanosheets are systematically investigated. First principles calculations are performed to verify its widely tunable bandgap from 0.43 eV for bulk to 1.58 eV for monolayer. The ultrafast carrier dynamic and non‐linear optical responses are investigated by non‐degenerated pump‐probe and open‐aperture Z‐scan methods, and the results indicate that 2D GeP nanosheets can present excellent broad‐band saturable absorption properties. Furthermore, the 2D GeP nanosheets‐based broad‐band saturable absorbers (SAs) and photodetectors are demonstrated. The results indicate that 2D GeP nanosheets can be used as excellent broad‐band optical modulators and detectors, which will arouse a considerable interest in exploring novel group IV–V 2D materials for broad‐band photonic and optoelectronic applications. [ABSTRACT FROM AUTHOR]

Abstract: The front cover artwork is provided by the groups of Li‐Min Liu (Beijing Computational Science Research Center, China) and Dongsheng Geng (University of Science and Technology Beijing, China). The cover picture shows that the as‐prepared Co3O4@NiFe layered double hydroxide electrode with a core–shell structure exhibits excellent electrocatalyst performance in overall water splitting. Read the full text of the Article at 10.1002/celc.201800194. [ABSTRACT FROM AUTHOR]

BaTeMo2O9 (BTM) single crystal, as a lead-free piezoelectric material, belongs to the monoclinic system, space group P21. We report the temperature dependence of the elastic constants by the transmission method over the range -50°C to 150°C. The first-order temperature coefficients of the elastic constant s44 is about 180 x 10?6/°C. Piezoelectric resonators based on BTM crystal using the thickness-stretching vibration and the shear vibration modes were designed and evaluated, which eliminated or minimized the influence of the off-principal axis coefficients. The Qm of one of the resonators is about 600. Our results show that the elastic constants have good temperature stability, and the resonators have already met the requirements for some piezoelectric applications. This study on the BTM crystal has revealed the application for the low-symmetry crystal. [ABSTRACT FROM PUBLISHER]