Photoelectric Measurements Research Articles

Signal processing method for measurement of sub-period speed fluctuation

Sub-period speed fluctuations of the measuring unit for a photoelectric scanning measurement network can directly affect the accuracy of the entire system. This study proposes a signal processing method for the measurement of subtle sub-period rotation speed fluctuation that includes two corresponding processing methods for different speed ranges. For the low-speed range, the specific steps included the calibration of the encoder gratings and relative measurement of the rotation speed. For the high-speed range, the corresponding signal processing method utilised the average speed, which represents the instantaneous speed at the middle moment. The sub-period speed fluctuation is very subtle for precise motion control, accounting for only 0.001% of the speed. Conventional methods cannot acquire the actual sub-period speed fluctuation due to the eccentricity error and scale error. However, the proposed method can measure the subtle sub-period speed fluctuation by filtering the interferences of the eccentricity and scale errors. The proposed method does not require any additional hardware and provides high accuracy.

Influence of the degradation processes on luminescent and photoelectrical properties of CsPbBr3 single crystals

The degradation processes under the influences of atmosphere moisture, current passage, and ultraviolet radiation were studied in CsPbBr3 single crystals grown by the vertical Bridgman-Stockbarger method. According to the results of luminescent and photoelectric measurements the formation of CsPb2Br5 and Cs4PbBr6 phases in the result of CsPbBr3 crystal degradation was observed. Based on the spectral measurements of the photodiffusion current, the position of the energy levels of the intrinsic structural defects VBr and (VBr + e) in the forbidden bandgap of the CsPbBr3 crystal and the change of the defects concentration was determined. It is assumed that the darkening of the crystals in the degradation process during the passage of current is due to the formation of metallic phases of lead.

Dual-quadrant photodetection in topological insulator and silicon-based heterojunction (n-Bi2Te2Se/p-Si)

Bi2Te2Se is a unique topological insulator (TI) with immense potential for spintronics and wideband photoelectric devices. Integration of Bi2Te2Se thin TI film was done with p-type Silicon (Si) substrate to formulate a lateral heterojunction. The transport properties of the n-Bi2Te2Se/p-Si heterojunction were studied and electrical characterization was done by I-V measurement. The electrical results confirmed the p-n heterojunction diode formation. The n-Bi2Te2Se/p-Si heterojunction diode had a good rectification ratio (~326 at ± 2 V) and a figure of merit under dark conditions. The photoelectric measurement of the n-Bi2Te2Se/p-Si heterojunction was done for a broad spectral range and incident power. Excellent dual-quadrant photodetection was observed for n-Bi2Te2Se/p-Si heterojunction from visible to near-infrared range with optimum performance at 900 nm incident light wavelength. Good responsivity and detectivity of 19.06 A/W, 8 ×1011 Jones at forward bias (+2 V) and 12.64 A/W, 7.72 ×1011 Jones at reverse bias (- 2 V) was observed at 900 nm wavelength of incident light. The device also had a convincing photoconductive gain of 26.31 (+2 V). The study provides a significant insight into the transport properties of the next-generation topological insulator/Si heterojunction-based photodetectors.

Photosensitivity of semiconducting SeTeSb glasses

Photo-electrical measurements are done on thin films of SeTeSb to see the influence of Sb additive on the light-induced conduction of binary Se80Te20 alloy. The ratio of electrical conductivity under dark to light conditions has been measured for measuring the photosensitivity of the samples. The activation energies of conduction for dark and light conditions (∆Eph) are also determined. The results reveal that both σph / σd and ∆Eph are reduced with an increase in Sb concentration. This indicates that density of defect states (DDS) is increased with an increase in the concentration of foreign element (i.e., Antimony) in thin films of these glassy systems. The cause of the increase in defects is also discussed. Start your abstract here…

Non-enzymatic glucose sensor and photocurrent performance of zinc oxide quantum dots supported multi-walled carbon nanotubes

Hybrid nanocomposites consisting of carbon nanotubes (CNT)/nanomaterial heterostructure play a key part in the excellent performance of nano-devices by coupling different functionalities. In this study, a glucose sensor was fabricated by immobilizing zinc oxide quantum dots (ZnO QDs) on multiwall carbon nanotubes (MWCNTs) nanocomposites using ultrasonication in an ease and economical method. ZnO QDs with ~ 3–8 nm diameters were grown and anchored on the surface of MWCNTs. These nanocomposites were characterized using different spectroscopy and microscopy techniques. XRD reveals the wurtzite structure of ZnO. TEM confirmed that ZnO QDs were anchored onto MWCNTs. The synthesized nanocomposites were applied as a sensor for electrochemical detection of glucose and as a photoelectric effect for photoelectric current measurements. The electrochemical properties of the MWCNT/ZnO QDs nanocomposite were enhanced significantly for glucose sensing when compared to pristine ZnO and MWCNTs. Results showed that ZnO QDs anchored over MWCNTs have a sensitivity of 9.36 µA µM−1 with repeatable results. The detection limit was found to be 0.208 µM. By applying nanocomposites on the sensor, the linear range could be extended from 0.1 to 2.5 µM, which increases the response time to less than 3 s. Experimental results also indicate that the sensor response is unaffected by the common interference agents during glucose-sensing such as sucrose, ascorbic acid, dopamine and uric acid. The proposed sensor was successfully employed to detect glucose levels in human urine samples with satisfactory outcomes.

Самоорганізовані метал-напівпровідниковімікро-та наноструктуриAu-GaAs для застосування у плазмонній фотовольтаїці

Au-GaAs metal-semiconductor composite microstructures have been prepared by an anisotropic etching of n-GaAs (100) wafers doped with Te (1016 to 1017 cm-3) with subsequent photostimulated chemical deposition of noble metal (Au) on formed semiconductor quasigratings. The microrelief topology of GaAs surface is controlled by the anisotropic etching conditions. Au metal was deposited on the structured GaAs surface as randomly placed nanoparticles of various shape and size and/or nanowires on the top of the hills of formed semiconductor microstructure. As the number of Au nanoparticles increases, they tend to localize on the ledges of the GaAs microrelief forming a system of approximately parallel nanowires. Obtained periodic structures with submicron to microns periods without Au nanoparticles and with deposited nanoparticles have been studied by means of scanning electron microscopy, optical spectroscopy (photoluminescence spectroscopy at room temperature), and photoelectric measurements. The decrease of the relative intensity of main photoluminescence band for samples with Au nanostructures compared to ones without nanoparticles deposition and simultaniously changes of the shape of photocurrent spectra of Au-GaAs microstructures have been observed. Such correlation in behaviour of measured spectra make formed Au-GaA metal-semiconductor microstructures perspective for the application in plasmonic photovoltaics.

模拟太阳光与高空自然光条件下航天用三结砷化镓太阳电池光电性能测量对比

模拟太阳光与高空自然光条件下航天用三结砷化镓太阳电池光电性能测量对比

Ultra-fast response polymer optical fiber oxygen measurement device and its preliminary experimental report on continuous dynamic change of arterial oxygen partial pressure under mechanical ventilation in living animals

Objective: We tried to implant the ultra-fast polymer optical fiber chemical oxygen sensor （POFCOS） into arterial blood vessel,connect with photoelectric conversion measurement system to record the continuous dynamic rapid changes of arterial PO2(PaO2) in whole living animals. It should be the experimental evidence for the new theory of holistic integrative physiology and medicine(HIPM) forexplain the mechanism of respiratory control and regulation in whole circusof respiration-circulation-metabolism. Methods: ①Fabrication of ultrafast POFCOS, calibration and its measuring system: The distal part of 2 m optical fiber was heated and pulled until it became a tapered tip. After cleaning and drying, the tip of 1 mm tapered optical fiber was dip-coated into the luminophore doped polymer solution, then was slowly pumped out while solvent was quickly evaporated to form an oxygen sensing tip, which was dried at room temperature for 24 hours. ②Animal experiments: Under general anesthesia and intubation, goatwas mechanically ventilated with 40%~60% oxygen. We exposed both right and left carotid arteries and the left femoral artery by skin cutting, and inserted the POFCOS directly into the arteries via indwelling catheter. The end of POFCOS were connected to the personal computer through optical fiber, excitation and detection Y-type optical fiber coupler through photoelectric conversion, so as we can realize the continuous dynamic response of living goat carotid PaO2 under mechanical ventilation. We mainly analyzed the intra-breath wave-form alternate increase and decrease of PaO2 and their time delay between lung and carotid arteries.We completes breathing control whole loop to explain the mechanism of mutual breathing and the switching of inspiration and exhalation. Results: The POFCOS has a very fast T90 response time was set 100 ms for liquid. When the heart rate of 40%~60% oxygen mechanical ventilated living goat was ~110 bpm, the PaO2 of left and right carotid artery showed a same wave-sizeup and down following with the inspiration and expiration of ventilator, with a range of up to 15 mmHg. There weresignificant noises of PaO2 change recorded in the left femoral artery. The lung-carotid artery time delay is 1.5~1.7 s after inhalation and exhalation, PaO2 at both left and right carotid arteries starts toincrease and decrease. After two-three heartbeats after the start of lung ventilation, thealternate up-down wave-form information of the arterialized pulmonary vein blood after pulmonary capillaries waspumpedby left ventricle to the position of peripheral chemoreceptors,thus realizing the whole cycle of inhalation and exhalation. It alternately interrupted inhalation, i.e. switching inhalation to exhalation, and then interrupted exhalation,i.e. switching exhalation to inhalation. Conclusion: The ultra-fast reactive implantableoxygen sensor and its measuring system can measure the physiological waveform changes of PaO2 in living animals, which can provide experimental evidence for explaining the mechanism of switching of inspiration-expiration in HIPM.

Values of Intelligent Alarm System Under Photoelectric Sensor Networks

This work was aimed to construct the intelligent alarm system with multiple photoelectric sensors as the core in this study. The system is first designed the circuit with microprocessor as the core, and then, there was a principle analysis of photoelectric measurement in the height, speed, and temperature to design a network mode of photoelectric sensor, circuits to control security doors and manage password, substation, and the monitoring center. The fusion approach based on deep learning is designed for the data collected by security alarm system. The 1-dimensional (1-D) representation of 2-dimensional (2-D) data is also designed according to the most of key information represented by the eigenvalue set of singular value decomposition of data matrix. The original 1-D signal sequence and the characteristics after 1-D were for data fusion, which is applied to identify, thus improving the accuracy of the alarm system and reducing its labor cost. During the experiment, the data fusion method proposed in this study is compared with naive bayes (NB) method and the weighted majority voting (WMV) method. The random data sets are generated with the help of a Gaussian function. The extreme learning machine (ELM) neural network classifier and k-nearest neighbors (KNN) classifier are carried in the alarm system designed in this study, respectively. The simulation analysis shows that WMV can obtain better performance of information classification compared with NB and data fusion methods, so the accuracy of classification is improved obviously. Besides, the fusion results accuracy of WMV is greatly higher than the other two.

A No-Reference Image Quality Comprehensive Assessment Method

On the basis of the research status of image quality comprehensive assessment, a no-reference image quality comprehensive assessment function model is proposed in this paper. First, the image quality is classified as contrast, sharpness, and signal-to-noise ratio (SNR), and the interrelation of each assessment index is researched and analyzed; second, the weights in the comprehensive assessment model are studied when only contrast, sharpness, and SNR are changed. Finally, on the basis of studying each kind of distortion separately, and considering the different types of image distortion, we studied how to determine the weights of each index in the comprehensive image quality assessment. The results show that the no-reference image quality comprehensive assessment function model proposed in this paper can better fit human visual perception, and it has a good correlation with Difference Mean Opinion Score (DMOS). Correlation Coefficient (CC) reached 0.8331, Spearman Rank Order Correlation Coefficient (SROCC) reached 0.8206, Mean Absolute Error (MAE) was only 0.0920, Root Mean Square Error (RMSE) was only 0.1122, Outlier Ratio (OR) was only 0.0365. The method proposed in this paper can be applied to photoelectric measurement equipment television system and give an accurate and reliable quality assessment to no reference television images.

Nanocomposite solar cells based on organic/inorganic (clonidine/Si) heterojunction with plasmonic Au nanoparticles

The peculiarities of optical and electrical properties of organic(clonidine)/inorganic(Si) heterojunction with plasmonic Au nanoparticles have been investigated by reflection spectra, photoelectric and current-voltage characteristics measurements. Porous nanostructured surfaces of silicon wafers were obtained by the method of selective chemical etching initiated by metal (gold) nanoparticles. Nanocomposites based on nanostructured silicon, clonidine and gold nanoparticles have been made. Two types of structure, namely, solar cells and photodiodes on the basis of such heterojunction were analysed. The reflection spectra of light confirmed the excitation of the plasmon mode in nanocomposites with gold nanoparticles. Photoelectric studies have shown an increase of the photocurrent of solar cells obtained as a result of using both nanostructured silicon and gold nanoparticles in 1.5 and 7 times, respectively. Study of the injection properties of the structures showed that the clonidine layer always facilitates the injection of current carriers, while gold nanoparticles limit the current in the case of a flat surface.

Central serous chorioretinopathy and heart rate variability analysis with a smartphone application

The purpose of this study was to quantitatively analyze heart rate variability (HRV) in patients with central serous chorioretinopathy (CSC) by using a smartphone-based application (ANBAI: DUMSCO Inc.) for measurement, and to clarify its relationships with CSC. The subjects were 64 CSC patients (mean age 48.7 ± 7.6 years, 57 males and 7 females). After providing consent, the patients downloaded ANBAI apps to their smartphones. HRV was measured by photoelectric volume pulse wave measurement with a smartphone camera each morning for a minimum of 1 week. The primary outcome was to analyze HRV by calculating log LF/HF (Low Frequency/High Frequency components), an index of autonomic tone, which was then compared with a control group of 35,226 individuals from the application. Secondary outcome measures included disease duration, body mass index, exercise habits, smoking history, steroid use, occupation, lifestyle regularity, psychological fatigue, physical fatigue, and average sleep time. The log LF/HF was significantly higher in the patient group than in the control group (P < 0.001). Log LF/HF was significantly lower in patients with exercise habits as a factor contributing to log LF/HF in the patient group (P = 0.019). Analysis of HRV in CSC patients showed an impairment of the autonomic nervous system. Exercise habits may also be associated with CSC.

Synthesis and characterization of single-bond fullerene dimer derivatives

Abstract

N-SrTiO3 nanoparticle/BiOBr nanosheet as 0D/2D heterojunctions for enhanced visible light photocatalytic dye degradation

A novel 0D/2D heterojunction N-SrTiO3/BiOBr (NSTO/BiOBr) was constructed by uniform dispersing of N-SrTiO3 nanoparticles on BiOBr nanosheets through a facial one-step precipitation method. All the synthesized NSTO/BiOBr composite photocatalysts with different N-SrTiO3 content were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflection spectroscopy (UV–Vis DRS), photoluminescence (PL) spectra, photocurrent response, electrochemical impedance spectra (EIS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N2 adsorption-desorption. The visible light rhodamine B degradation results revealed that the formation of 0D/2D heterojunction NSTO/BiOBr results in improved photodegradation activity as compared with N-SrTiO3 and BiOBr, and NSTO/BiOBr with the 18% weight percentage of N-SrTiO3 is most effective among all the NSTO/BiOBr nanocomposites. The activity comparison of 18% NSTO/BiOBr with that of pure NSTO and BiOBr also conforms to their corresponding photoelectric response and electron transfer impedance measurements. Finally, RhB degradation mechanism over NSTO/BiOBr composite catalyst were proposed.

Far-zone behaviors of scattering-induced statistical properties of partially polarized spatially and spectrally partially coherent electromagnetic pulsed beam**Project supported by the National Natural Science Foundation of China (Grant No. 11504286), the Natural Science Basic Research Program of Shaanxi Province, China (Grant No. 2019JM-470), the Fund from the International Technology Collaborative Center for Advanced Optical Manufacturing and Optoelectronic Measurement, and the Science

In this study, we explore the far-zero behaviors of a scattered partially polarized spatially and spectrally partially coherent electromagnetic pulsed beam irradiating on a deterministic medium. The analytical formula for the cross-spectral density matrix elements of this beam in the spherical coordinate system is derived. Within the framework of the first-order Born approximation, the effects of the scattering angle θ, the source parameters (i.e., the pulse duration T0 and the temporal coherence length Tcxx), and the scatterer parameter (i.e., the effective width of the medium σR) on the spectral density, the spectral shift, the spectral degree of polarization, and the degree of spectral coherence of the scattered source in the far-zero field are studied numerically and comparatively. Our work improves the scattering theory of stochastic electromagnetic beams and it may be useful for the applications involving the interaction between incident light waves and scattering media.

Ternary MoSe2xTe2−2x alloy with tunable band gap for electronic and optoelectronic transistors

Two-dimensional transition metal dichalcogenide (2D TMDs) alloys, consisting of three or more elements, offer a luxury variety of chemical and physical properties through elemental ratio alteration, thus may provide ideal candidate with tunable band gap for specific electrical applications. In this work, we demonstrate a high-quality layered MoSe2xTe2−2x (x = 0 ∼ 1) alloy synthesized via one-step chemical vapor transport method for high-performance electronic and optoelectronic transistors. Our characterizations reveal the obtained ternary alloy forming high-quality single crystal layers with 2H phase. Interestingly, the electronic transistors fabricated on MoSe2xTe2−2x thin layers (6 ∼ 7 layers) display an anomalous transition from ambipolar to n-type in conductive characteristics with the increase of substitution x value. The subsequent photoelectrical measurements exhibit that high on-off ratio for every ratio (x = 0.18, 0.38, 0.67, 0.83) with optical band gap in the range of 1.6 eV and 1.1 eV (near infrared). The optimized MoSe0.37Te1.63–based transistor can achieve up to ∼107 Ion/Ioff and 105 Iph/Idark ratio, 100 mA W−1 photo-responsivity and 2.38% external quantum efficiency with high photoresponsivity. Thus, such ternary MoSe2xTe2−2x alloys may pose a great potential for 2D-based electronic and photoelectronic applications.

Development of a portable cold air plasma jet device and observation of its photo ionization process

Photo ionization plays a critical role in the formation and propagation of atmospheric pressure plasma jet plumes. But in experiments, it is very difficult to observe the photo ionization due to its relative lower density of photo electrons. In the present study, we develop a portable cold air plasma jet device and observe the ionization wave in a dc spark air plasma jet. The discharge images acquired by an ICCD camera show that the ionization wave front performs as a quickly moving bright ball. Breakdown could take place at another side of the quartz plate or pork tissue layer (6 mm thick), which suggests that the ionization should be attributed to photo ionization. The laser schlieren images indicate there is propagation of a shock wave along with the plasma bullet. Based on the photo ionization theory and the photo-electric measurement, the direct photo ionization and multistage photo ionization are the main factors in charge of generating the cold air plasma jet. In addition, the plasma jet outside of the cathode nozzle is colder than 320 K and can be touched safely by a human. In view of the plasma jet including a large amount of active particles, such as NO, O, OH, emitted photons, etc, the proposed portable cold air plasma jet device could be qualified for plasma bio-medicine applications.

Photoelectric Silk via Genetic Encoding and Bioassisted Plasmonics.

Genetically encoded photoelectric silk that can convert photons to electrons (light to electricity) over a wide visible range in a self-power mode is reported. As silk is a versatile host material with electrical conductivity, biocompatibility, and processability, a photoelectric protein is genetically fused with silk by silkworm transgenesis. Specifically, mKate2, which is conventionally known as a far-red fluorescent protein, is used as a photoelectric protein. Characterization of the electrochemical and optical properties of mKate2 silk allows designing a photoelectric measurement system. A series of in situ photocurrent experiments support the sensitive and stable performance of photoelectric conversion. In addition, as a plasmonic nanomaterial with a broad spectral resonance, titanium nitride (TiN) nanoparticles are biologically hybridized into the silk glands, taking full advantage of the silkworms' open circulatory system as well as the absorption band of mKate2 silk. This biological hybridization via direct feeding of TiN nanoparticles further enhances the overall photoelectric conversion ability of mKate2 silk. It is envisioned that the biologically derived photoelectric protein, its ecofriendly scalable production by transgenic silkworms, and the bioassisted plasmonic hybridization can potentially broaden the biomaterial choices for developing next-generation biosensing, retina prosthesis, and neurostimulation applications.

Recognition method of the dual-objective in a linear array CCD-based improved photoelectric measurement system using two lasers with different wavelengths

This paper proposes a dual-objective recognition method using a linear array CCD–based improved photoelectric measurement system with two different lasers. Firstly, the measurement system consists of a linear color CCD camera, two lasers with different wavelengths and a projection board. Next, its measurement principle and image process are introduced, respectively. Using the channel separation, signal recognition and mutual comparison of the image can be captured by the CCD camera, and then the coordinates of the two objectives are obtained. Simulation experiments show that the error standard deviations of coordinate measurement in the X and Y directions are 1.2 mm and 4.1 mm, respectively, if the effective detection area is 1 m × 1 m. The method can meet the requirements of the measurement.

UV Photodetector Based on p-NiO film/n-Si Heterojunction Prepared by Thermal Oxidation

In this work, p-type NiO film was grown on n-type Si substrate as UV photodetector. NiO film was prepared over n-type Si (100) through two-step method. First, metallic Ni film was deposited on Si wafer using thermal evaporator; then the film was thermally oxidized in a tube furnace at 500 °C for 3 h to get NiO film. The film revealed polycrystalline structure of cubic NiO phase as confirmed from XRD characterization. The diffraction peaks ascribed to metallic Ni film were not detected in the XRD pattern which implies that Ni film was completely converted into NiO. For photoelectric measurements of NiO/Si heterojunction, Ag metal was deposited on both Si substrate and NiO film as a contact. The current-voltage curves exhibited rectifying behaviour with ideality factor and barrier height of 25 and 0.96 eV, respectively. NiO/Si heterojunction showed appreciable photoresponse towards UV light at wavelength of 365 nm. The responsivity, rise time and fall time of the photodiode were measured as 0.16 A/W, 1.7 s and 0.85 s, respectively at bias voltage of -5 V.