Photoelectric Measurements Research Articles

Based on an all-dielectric metamaterial sensing strategy to reveal the effect of acoustic AO effect on optical fiber transmission performance

Abstract Here, a sensing scheme based on metamaterial is proposed and applied to measure the acousto-optic (AO) effect on the transmission performance of optical fiber. The AO effect in the fiber is modulated through optimizing the amplitude and frequency of the sound wave, which is different from the traditional photoelectric measurement scheme. The AO effect can be enhanced with the drive voltage of the sound wave generator increasing, which leads to the transmission performance of the fiber be suppressed. On the contrary, the attenuation coefficient and group velocity of the fiber are basically stable. The time for sound waves to enter and leave the AO effect region is extended. Moreover, the AO effect is also enhanced as the sound frequency gradually approached the resonant frequency. These measurements reveal the physical mechanism of the AO effect of optical fibers and validate the feasibility of this proposed metamaterial sensing scheme.

Dramatic switchable polarities in conduction type and self-driven photocurrent of BiI3 via pressure engineering.

The intentional manipulation of carrier characteristics serves as a fundamental principle underlying various energy-related and optoelectronic semiconductor technologies. However, achieving switchable and reversible control of the polarity within a single material to design optimized devices remains a significant challenge. Herein, we successfully achieved dramatic reversible p-n switching during the semiconductor‒semiconductor phase transition in BiI3 via pressure, accompanied by a substantial improvement in their photoelectric properties. Carrier polarity flipping was monitored by measuring the photocurrent dominated by the photothermoelectric (PTE) effect in a zero-bias two-terminal device. Accompanying the p-n transition, a switch between positive and negative photocurrents was observed in BiI3, providing a feasible method to determine the conduction type of materials via photoelectric measurements. Furthermore, the combined effects of the photoconductivity and PTE mechanism improved the photoresponse and extended the detection bandwidth to encompass the optical communication waveband (1650nm) under an external bias. The remarkable photoelectric properties were attributed to the enhanced energy band dispersion and increased charge density of BiI3 under pressure. These findings highlight the effective and flexible modulation of carrier properties through pressure engineering and provide a foundation for designing and implementing multifunctional logic circuits and optoelectronic devices.

Development of a Shoelace Tensile Testing System and Investigation into the Effects of Different Running Speeds on Shoelace Tensile Variation

This study investigated the validity and sensitivity of a custom-made shoelace tensile testing system. The aim was to analyze the distribution pattern of shoelace tension in different positions and under different tightness levels during running. Mechanical tests were conducted using 16 weights, and various statistical analyses, including linear regression, Bland-Altman plots, coefficient of variation, and intraclass correlation coefficient, were performed to assess the system’s validity. Fifteen male amateur runners participated in the study, and three conditions (loose, comfortable, and tight) were measured during an upright stance. The system utilized VICON motion systems, a Kistler force plate, and a Photoelectric gate speed measurement system. Results showed a linear relationship between voltage and load at the three sensors (R2 ≥ 0.9997). Bland-Altman plots demonstrated 95% prediction intervals within ± 1.96SD from zero for all sensors. The average coefficient of variation for each sensor was less than 0.38%. Intraclass correlation coefficient values were larger than 0.999 (p<0.0001) for each sensor. The peak tension of the front shoelace was greater than that of the front and middle when the shoelace was loose and tight. The rear shoelace had the highest tension force. The study also found that shoelace tension varied throughout the gait cycle during running. Overall, this research provides a novel and validated method for measuring shoelace tensile stress, which has implications for developing automatic shoelace fastening systems.

Photoelectric sensor array-based measurement method for the key motion parameters of the small flying object considering non-uniform curve trajectory

PurposeThe paper aims to accurately measure the key motion parameters, such as velocity, azimuth and pitch angle, of the small flying object with a non-uniform curve trajectory. It proposes a measurement method and its calculation model of non-uniform curve trajectory using a photoelectric sensor array.Design/methodology/approachFirst, the basic composition of the measurement system and mechanism of photoelectric sensor array are described, respectively. Second, a non-uniform curve mathematical measurement model is constructed differently from the traditional linear trajectory, taking into account the influence of gravity and air resistance. Third, the measurement error of the system is analyzed through numerical simulation. Finally, the accuracy and feasibility of the approach are verified by live-ammunition experiments.FindingsThe results show that the systematic error of the hitting point coordinates can be reduced by 9% compared to the traditional linear measurement model. Consequently, this method can meet the higher measurement requirement for the key motion parameters of the small flying object under the non-uniform curve trajectory. Research limitations/implications (if applicable)- although the approach itself is generalizable, the method is unable to detect the motion parameters of multiple small flying objects.Research limitations/implicationsAlthough the approach itself is generalizable, the method is unable to detect the motion parameters of the multiple small flying objects.Practical implicationsIt is evident that the proposed non-uniform curve measurement model is more precise in quantifying the essential characteristics of the small flying object, particularly in consideration of the environmental conditions.Social implicationsThe precise measurement of the key motion parameters of the small flying object can facilitate the enhancement of the protective performance of protective materials.Originality/valueA novel approach to measurement is proposed, which differs from the conventional uniform trajectory model. To this end, the space construction of the photoelectric sensor array is optimized. The number of the sensors is revised.

Honeycomb shaped carbon dopped 1T-2H-MoS2 heterojunction counter electrode with high short current for dye sensitized solar cells

Honeycomb shaped carbon dopped 1T-2H-MoS2 heterojunction counter electrode with high short current for dye sensitized solar cells

Enhanced charge separation at the interface of Cu2O/CuSCN composite thin films synthesized by electrodeposition technique

This study focuses on the synthesis and characterization of hole transport layers (HTLs) for solar cells, par- ticularly copper(I) thiocyanate (CuSCN) and cuprous oxide (Cu2O), synthesized via electrodeposition tech- niques. CuSCN and Cu2O offer promising properties for efficient charge transport in photovoltaic devices. The synthesis processes involve precise control of deposition parameters to achieve desired film morpholo- gies and properties. Characterization techniques including scanning electron microscopy (SEM), atomic force microscopy (AFM), and ultraviolet-visible (UV-Vis) spectroscopy provide insights into film morphology and optical properties. Optimization of synthesis parameters for Cu2O films is explored to enhance their electrical properties. Photoelectric response measurements indicate improved charge separation at the interface of Cu2O/CuSCN composite films. These findings can contribute to the advancement of solar cell technology. Furthermore, the study extends its exploration to the fabrication of Cu2O by electrodeposition at different pH levels. SEM and X-ray diffraction (XRD) analyses reveal the impact of deposition parameters on film mor- phology and crystal structure, providing valuable insights for tailored synthesis approaches. Overall, this comprehensive study not only advances the understanding of HTL materials synthesis and optimization but also provides valuable guidance for the development of high-efficiency and stable solar cell devices.

Pressure-Induced Structural Transition and Enhanced Photoelectric Properties of Tm2S3

Abstract Rare earth sesquisulfides have drawn growing attention in photoelectric applications because of their excellent electronic and photoelectric properties upon compression. We investigate the structural, electrical, and photoelectric properties of Tm2S3 under high pressure through electrical impedance, UV-vis absorption, Raman spectroscopy, x-ray diffraction, and photoelectric measurements. It is found that δ-Tm2S3 transforms into high-pressure α-phase around 5 GPa, accompanied by a substantial reduction in atomic distance, bandgap, and resistivity. Consequently, the photocurrent density and responsivity of Tm2S3 exhibit dramatic increase behavior, achieving five orders of magnitude enhancement in α-phase compared with the initial δ-Tm2S3. Moreover, α-phase maintains a high photocurrent responsivity of three orders of magnitude after unloading. This work demonstrates significant enhancement of the photoelectric properties of Tm2S3 by applying pressure, which paves the way for improving the performance of future photoelectric devices.

High-Precision Measurement of Microscales Based on Optoelectronics and Image Integration Method.

Currently, there are various types of microscales and the conventional line detection system usually has only one detection method, which is difficult to adapt to the diverse calibration needs of microscales. This article investigates the high-precision measurement method of a microscale based on optoelectronics and the image integration method to solve the diversified calibration needs of microscales. The automatic measurement and processing system integrates two methods: the photoelectric signal measurement method and the photoelectric image measurement method. This article studies the smooth motion method based on ordinary linear guides, investigates the method of reducing the cosine error of a small-range interference length measurement, proposes an image-based line positioning method, and studies the edge and center recognition algorithms of the line. According to the experimental data, the system's measurement accuracy was analyzed using the photoelectric signal measurement method to measure the 1 mm microscale, the maximum difference from the reference value was 0.105 μm, the standard uncertainty was 0.068 μm, and the absolute value of normalized error was less than 1. The accuracy of the image measurement method to measure the 1 mm microscale was consistent with that of the photoelectric signal method. The results show good consistency in the measurement results between the two methods of the integrated measurement system. The photoelectric signal method has the technical characteristics of high measurement efficiency and high accuracy, while the pixel-based measurement of the image method has two-dimensional measurement characteristics, which can realize measurements that cannot be realized by the photoelectric signal method; therefore, the measurement system of optoelectronics and image integration is characterized by high precision and a wide range of measurement adaptations.

Dual-pathway charge transfer mechanism of anatase/rutile TiO2-Ag3PO4 hollow photocatalyst promotes efficient degradation of pesticides

Exploring high-performance photocatalysts still remains a big challenge due to poor charge separation efficiency. Herein, we prepare a novel anatase/rutile TiO2-Ag3PO4 hollow photocatalyst (A/R-TiO2-Ag3PO4) for addressing this challenge. Microstructural characterization and photoelectric measurements confirm that the synergy of hollow structure and dual-heterojunction can provide abundant active sites and boost efficient charge separation through dual-pathway charge transfer mechanism. The A/R-TiO2-Ag3PO4 photocatalyst exhibits the highest photocurrent density (15.25µAcm-2), which is 8.4 and 5.2 times than that of A-TiO2-Ag3PO4 (1.82µAcm-2) and P25-Ag3PO4 (2.93µAcm-2), respectively. Photo-degradation experiment shows that A/R-TiO2-Ag3PO4 presents a high degradation percentage (98.7%) of thiamethoxam (THX) within 30min, which is 1.45 and 1.23 times than that of A-TiO2-Ag3PO4 (68.1%) and P25-Ag3PO4 (80.7%), respectively. Furthermore, the degradation percentage of THX by A/R-TiO2-Ag3PO4 is as high as 96.4% after seven successive cycles, indicating excellent cycling stability. Therefore, this work provides a new insight into exploring other high-performance photocatalysts by combining hollow structure and dual-heterojunction.

Nanofibrous La0.95K0.05MnO3 perovskite with improved photoelectrical properties for photocatalytic degradation of antibiotics

Potassium doped lanthanum manganese perovskite oxides, La1−xKxMnO3, with nanofibrous structure, are prepared and used for Photo-Fenton degradation of antibiotics, including ciprofloxacin (CIP), tetracycline (TC), and sulfathiazole (ST). Effects of K doping on the textural structure, optical property, band gap and surface chemistry of LaMnO3 are investigated, showing that La0.95K0.05MnO3 (LKMO-5) has the optimal properties. The photoelectric measurements, including photoluminescence (PL), photocurrent response (PCR) and electrochemical impedance spectroscopy (EIS), also suggest that the LKMO-5 has the best electron–hole separation efficiency, the most amounts of irradiated electrons and the lowest impedance. Photocatalytic tests indicate that LKMO-5 not only shows the best activity for CIP degradation, but also exhibits good stability in the reaction, with negligible activity loss within four cycles. Mechanism investigations, explored by the radical trapping experiments and with the reference of band positions, indicate that superoxide radical ions (·O2−) and holes (h+) are the major reactive species of the reaction.

Novel CoFe2O4/Bi2WO6 S-scheme heterostructure photocatalyst for effective and rapid visible-light-driven reduction of toxic nitrobenzene into industrially valuable aniline

Novel CoFe2O4/Bi2WO6 S-scheme heterostructure photocatalyst for effective and rapid visible-light-driven reduction of toxic nitrobenzene into industrially valuable aniline

Dual Heterogeneous Structures Promote Electrochemical Properties and Photocatalytic Hydrogen Evolution for Inverse Opal ZnO/ZnS/Co3O4 Crystals.

Potocatalytic hydrogen evolution represnets a promising way to achieve renewable energy sources. Dual heterojunctions with an inverse opal structure are proposed for addressing fundamental challenges (low surface area, inefficient light absorption, and poor charge separation) in photocatalytic water splitting. Inverse opal structure and Co3O4 were introduced to design and synthesize a ZnO/ZnS/Co3O4 (IO-ZnO/ZnS/Co3O4) photocatalyst. Morphology characterizations and photoelectric measurements reveal that the introduction of three-dimensional (3D) structures and dual heterojunctions improves light utilization efficiency and accelerates charge separation, greatly promoting photoelectric performance. The as-prepared IO-ZnO/ZnS/Co3O4 manifests superior photocurrent density (0.49 mA/cm2), which is 4 times higher than that of IO-ZnO/ZnS due to the existence of dual heterojunctions. The result is further confirmed by an enhanced H2 production rate (153.01 μmol/g/h) in pure water. Notably, excellent cycling stability is achieved in pure water because Co3O4 can rapidly capture photogenerated holes to inhibit severe photocorrosion of ZnO/ZnS. Therefore, this work presents a new insight into inhibiting photocorrosion of metal sulfides and promoting their photoelectric performance by combining 3D structures and dual heterojunctions.

Band Alignment Transition and Enhanced Performance in Vertical SnS2/MoS2 van der Waals Photodetectors.

The strong light-matter interaction and naturally passivated surfaces of van der Waals materials make heterojunctions of such materials ideal candidates for high-performance photodetectors. In this study, we fabricated SnS2/MoS2 van der Waals heterojunctions and investigated their photoelectric properties. Using an applied gate voltage, we can effectively alter the band arrangement and achieve a transition in type II and type I junctions. It is found that the SnS2/MoS2 van der Waals heterostructures are type II heterojunctions when the gate voltage is above -25 V. Below this gate voltage, the heterojunctions become type I. Photoelectric measurements under various wavelengths of incident light reveal enhanced sensitivity in the ultraviolet region and a broadband sensing range from 400 to 800 nm. Moreover, due to the transition from type II to type I band alignment, the measured photocurrent saturates at a specific gate voltage, and this value depends crucially on the bias voltage and light wavelength, providing a potential avenue for designing compact spectrometers.

ZnPc based multifunctional devices designed as fast capacitors, rectifiers, infrared detectors and microwave resonators adequate for 6 G technology applications

Herein Zinc phthalocyanine (ZnPc) based multifunctional devices are fabricated and characterized. The device fabrication included formation of an Au nanosheets onto n-Si wafers and coating these nanosheets with 500 nm thick ZnPc layer. Silver and platinum were used to form a Schottky and an ohmic contacts with n-Si and ZnPc, respectively. The device hybrid structure (Ag/n-Si/Au/p-ZnPc/Pt; abbreviated as ASZ) is composed of Ag/n-Si Schottky arm and p- and n- layers forming pn junction separated by Au nanosheets. Electrical and photoelectrical measurements on the ASZ devices have shown their ability to perform as conventional metal-oxide-semiconductor capacitors (CMOS). These CMOS devices showed light and frequency controlled charge accumulation, depletion and inversion mechanisms within the range of 1.0–50 MHz. The flat band and threshold voltages of the ASZ capacitors are engineered by the imposed ac signal frequency and by infrared (IR) light. In addition, ASZ devices performed as biasing controlled IR photosensors and as current rectifiers. A rectification ratio of 103, IR light sensitivity of 39, specific detectivity of .96 ×109 Jones and current responsivity exceeding 9.0 mA W−1 are recorded at biasing voltage of 4.5 V. Moreover ASZ devices displayed microwave resonator characteristics presented by negative capacitance effect, resonance –antiresonance phenomena and high microwave cutoff frequency. The latter is larger than 10 GHz nominating the device for 6 G technology applications.

Remarkable upgrade of hydrogen evolution activity up to 40.8 folds and mechanistic investigation of expediting charge transfer achieved by Bi2O3-modified TiO2 photocatalyst

Remarkable upgrade of hydrogen evolution activity up to 40.8 folds and mechanistic investigation of expediting charge transfer achieved by Bi2O3-modified TiO2 photocatalyst

Macrocycle-on-COF photocatalyst constructed by in-situ linker exchange for efficient photocatalytic CO2 cycloaddition

Macrocycle-on-COF photocatalyst constructed by in-situ linker exchange for efficient photocatalytic CO2 cycloaddition

Optoelectronic Torque Measurement System Based on SAPSO-RBF Algorithm.

The torque is a significant indicator reflecting the comprehensive operational characteristics of a power system. Thus, accurate torque measurement plays a pivotal role in ensuring the safety and stability of the system. However, conventional torque measurement systems predominantly rely on strain gauges adhered to the shaft, often leading to reduced accuracy, poor repeatability, and non-traceability due to the influence of strain gauge adhesion. To tackle the challenge, this paper introduces a photoelectric torque measurement system. Quadrants of photoelectric sensors are employed to capture minute deformations induced by torque on the rotational axis, converting them into measurable voltage. Subsequently, the system employs the radial basis function neural network optimized by simulated annealing combined with particle swarm algorithm (SAPSO-RBF) to establish a correlation between measured torque values and standard references, thereby calibrating the measured values. Experimental results affirm the system's capability to accurately determine torque measurements and execute calibration, minimizing measurement errors to 0.92%.

High-Range and High-Linearity 2D Angle Measurement System for a Fast Steering Mirror.

In order to solve the problem of the insufficient range of the traditional fast mirror (FSM) angle measurement system in practical applications, a 2D large-angle FSM photoelectric angle measurement system based on the principle of diffuse reflection is proposed. A mathematical model of the angle measurement system is established by combining the physical properties of the diffuse reflecting plate, such as the rotation angle, rotation center, rotation radius, reflection coefficient and the radius of the diffuse reflecting surface. This paper proposes a method that optimizes the degree of nonlinearity based on this mathematical model. The system is designed and tested. The experimental results show that changing the diffuse reflection surface area can improve the nonlinearity of the angle measurement system effectively. When the radius of the diffuse reflection surface is 3.3 mm, the range is ±20°, the non-linearity is 0.74%, and the resolution can reach up to 2.3″. The system's body is simple and compact. It is also capable of measuring a wider range of angles while linearity is guaranteed.

ACTIVITY CYCLES OF SINGLE G5 III-IV GIANT HD 199178

A unique series of photometric data has been obtained for a period of more than a hundred years for the rapidly rotating single G5 III–IV giant HD 199178 (V1794 Cyg) belonging to the group of stars of the FK Com type. Our analysis of the long-term periodicity of the activity of this star is based on all available measurements of its brightness in B filter. To assess the brightness of HD 199178 in the era preceding photoelectric and CCD observations measurements were made using photographic plates from the archive of the SAI MSU at the Krasnopresnenskaya Observatory of Moscow State University in Moscow (4 plates taken from 1898 to 1903 and 41 plates obtained from 1935 to 1958). As a result, a total of 2142 estimates of the brightness of the star in the B filter were considered . They have a unique duration of 118.3 years and cover the time interval from 1898 to July 2016. Evidence of the existence of long-term cycles of photometric variability with values of the order of 25–60 years has been found. It is assumed that there are possible activity cycles of 2000, 3165, 5050, 9000 and 21600 days (5.5, 8.7, 16.6, 24.7 and 59.2 years). The results obtained are compared with other estimates of activity cycles of HD 199178. The existence of a cycle of 8.7–9 years should be recognized as the most reliable. It is found that to combine data into a single array the conversion of values B into values V using the average value of the color index (\(B{\kern 1pt} - {\kern 1pt} V\)) is not possible due to changes (including cyclical) of (\(B{\kern 1pt} - {\kern 1pt} V\)) with time.

Highly Water-Stable Zinc Based Metal-Organic Framework: Antibacterial, Photocatalytic Degradation and Photoelectric Responses.

A reported water-stable Zn-MOF ([Zn(L)2(bpa)(H2O)2]·2H2O, H2L = 5-(2-cyanophenoxy) isophthalic acid has been prepared via a low-cost, general and efficient hydrothermal method. It is worth noting the structural features of Zn-MOF which exhibit the unsaturated metal site and the main non-covalent interactions including O⋯H, N⋯H and π-π stacking interactions, which lead to strong antibacterial and good tetracycline degradation ability. The average diameter of the Zn-MOF inhibition zone against Escherichia coli and Staphylococcus aureus was 12.22 mm and 10.10 mm, respectively. Further, the water-stable Zn-MOF can be employed as the effective photocatalyst for the photodegradation of tetracycline, achieving results of 67% within 50 min, and it has good cyclic stability. In addition, the photodegradation mechanism was studied using UV-vis diffuse reflection spectroscopy (UV-VIS DRS) and valence-band X-ray photoelectron spectroscopy (VB-XPS) combined with the ESR profile of Zn-MOF, which suggest that ·O2- is the main active species responsible for tetracycline photodegradation. Also, the photoelectric measurement results show that Zn-MOF has a good photocurrent generation performance under light. This provides us with a new perspective to investigate Zn-MOF materials as a suitable multifunctional platform for future environmental improvement applications.