Photoelectric Signal Research Articles

Near-Infrared Dual-Range Methane Sensor Using the OAIC-HC Mode Based on VMD-SG-Assisted Optical Noise Suppression.

Based on tunable diode laser absorption spectroscopy and off-axis integrated cavity output spectroscopy, a dual-range methane hybrid sensor was constructed utilizing the overtone absorption band of CH4 gas molecules at 1653.7 nm. By simultaneously utilizing an off-axis integrated cavity and Herriott cell with an effective absorption path of 11 and 405 m, respectively, the two received photoelectric signals are decomposed into different frequency components by VMD and then reconstructed after SG filtering. Applying the global optimization algorithm DA-ELM to CH4 concentration inversion, the correlation coefficient R2 is as high as 0.9995. Through long-term stability verification, the instrument's standard deviation at 1 ppm is 27 ppb. After Allan-Werle deviation analysis, the sensor's limit of detection is 2.298 ppb at an integration time of 138 s. Using the self-developed sensor, the detection of dual-range trace CH4 gas is achieved, enabling a dynamic detection range of trace CH4 gas ranging from 400 ppb to 1000 ppm. The sensor realizes dual-range methane trace detection and actively controls methane emissions to improve environmental quality while taking into account the safety benefits of reducing production accidents.

Development of photoelectrochemical immunosensor based on halide perovskite protected by organometallic compounds for determining interleukin-17A (IL-17A).

The overexpression of interleukin-17A (IL-17A) is closely associated with the pathogenesis of autoimmune diseases and cancer, rendering precise identification of IL-17A level critical for disease diagnosis and prognosis monitoring. In this study, CsPbBr3 nanoclusters (NCs) were embedded in C16H14Br2O6Pb2 organometallic compound (Pb-MA MOC) via a hot injection approach. Through this way, the issue of CsPbBr3 NCs susceptible to decomposition in water was solved, and the photocurrent intensity that isgenerated by CsPbBr3 was significantly enhanced. A highly sensitive photoelectrochemical (PEC) sensor for detecting IL-17A in human serum was developed using CsPbBr3/Pb-MA as the photoactive material. The electrode was initially modified with CsPbBr3/Pb-MA. Then, antibody-modified Fe3O4 magnetic nanoparticles (MNs) with target analyte IL-17A captured, and IL-17A antibody-modified Au@CuNi diatomic catalyst (DAC) formed sandwich immune complex structure on theelectrode. The existence of CuNi DAC led to a substantial reduction in photoelectric signal intensity due to oxidation of ascorbic acid in thesupporting electrolyte. The photocurrent intensity exhibited linear correlation with IL-17A concentration within the range 15-750pg/mL, and achieving an impressive detection limit of1pg/mL. Moreover, the sensor was successfully applied to the determination of IL-17A in human serum, suggesting its potential clinical applications.

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.

High-throughput detection of Src kinase through cathodic photoelectrochemistry

Photoelectrochemical (PEC) bioanalysis has recently become a perspective pathway for biomolecular sensing, presenting new insights for disease diagnosis and treatment. Herein, we present a new cathodic PEC platform for detecting Src kinase in a label-free, non-immobilized, and high-throughput mode. Specifically, treatment of the tyrosine-containing peptide by tyrosine kinase produced an ortho-diphenol structure of tyrosine that can in situ introduce oxygen vacancies (Ov) on the surface of NiTiO3 material, which led to the augmentation of the photoelectric signal. While the presence of the target Src kinase phosphorylated tyrosine in substrate peptide and blocked the surface Ov formation onto NiTiO3. Such a phenomenon was correlated with the Src kinase detection in terms of good sensitivity and selectivity, achieving the linear detection range of 0.001–2.0 μg/mL and the detection limit of 3.0×10−4 μg/mL (S/N=3). For Src kinase detection, this is a superior strategy to some classical methods in terms of easy operation, rapid response, and cost effectiveness. This study features the first exploration of cathodic photoelectrochemistry for Src kinase detection and is expected to expand its application in probing more disease related targets with unknown possibilities.

Design and characterization of a novel turbidity sensor based on quadrature demodulation

Abstract Turbidity is regarded as a comprehensive indicator in water quality monitoring, and the turbidity sensor deployed in the water supply network can record the dynamic changes of water quality in time. However, the weak photoelectric signal from the photodetector contains a quantity of noise. In order to improve signal-to-noise ratio (SNR), a novel on-line turbidity sensor based on quadrature demodulation principle has been proposed in this paper. A near-infrared light-emitting diode (LED) with a wavelength of 860 nm was selected as a stable monochromatic light source, and a photodiode (PD) with an angle of 90° to the incident light from the LED was selected as the photodetector. Using signal modulation and demodulation technology, the weak photoelectric signal extraction, conversion, amplification and output of the turbidity sensor were realized through the effective integration. A corresponding test apparatus of the turbidity sensor was established and experimental results showed that within a 0~5 NTU measurement range, the turbidity sensor had good linearity and stability, the relative measurement error was within ±1% and the limit of detection could reach as low as 0.0049 NTU. The developed turbidity sensor has good detection performance and can meet the needs of low turbidity detection of drinking water.

Self-powered multifunctional platform based on dual-photoelectrode for dual-mode detection and inactivation of Salmonella enteritidis

Self-powered photoelectrochemical (PEC) sensing is a novel sensing modality. The introduction of dual-mode sensing and photoelectrocatalysis in a self-powered system enables both detection and sterilization purposes. To this end, herein, a self-powered multifunctional platform for the photoelectrochemical-fluorescence (PEC-FL) detection and in-situ inactivation of Salmonella enteritidis (SE) was constructed. The platform utilized Bi4NbO8Cl/V2CTx/FTO as a photoanode and CuInS2/FTO as a photocathode and incubated quantum dot (QDs) signaling probes on the surface of the photocathode. During detection, the system drives the transfer of photogenerated electrons between the dual photoelectrodes through the Fermi energy level difference. The photoanode amplifies the photoelectric signal, while the photocathode is solely dedicated to the immune recognition process. QDs provide an additional fluorescence signal to the system. Under optimal experimental conditions, the multifunctional platform achieves detection limits of 3.2 and 5.3 CFU/mL in PEC and FL modes respectively, with a detection range of 2.91 × 102 to 2.91 × 108 CFU/mL. With the application of an external bias voltage, it further promotes electron transfer between the dual photoelectrodes, inhibits the recombination of photogenerated electrons and holes. It generates a significant amount of superoxide radicals (·O2−) in the cathodic region, resulting in strong sterilization efficiency (99%). The constructed self-powered multifunctional platform exhibits high sensitivity and sterilization efficiency, it provides a feasible and effective strategy to enhance the comprehensive capability of self-powered sensors.

Bio-Inspired Photoelectric Dual-Mode Sensor Based on Photonic Crystals for Human Motion Sensing and Monitoring.

Photoelectric dual-mode sensors, which respond to strain signal through photoelectric dual-signals, hold great promise as wearable sensors in human motion monitoring. In this work, a photoelectric dual-mode sensor based on photonic crystals hydrogel was developed for human joint motion detection. The optical signal of the sensor originated from the structural color of photonic crystals, which was achieved by tuning the polymethyl methacrylate (PMMA) microspheres diameter. The reflective peak of the sensor, based on 250 nm PMMA PCs, shifted from 623 nm to 492 nm with 100% strain. Graphene was employed to enhance the electrical signal of the sensor, resulting in a conductivity increase from 9.33 × 10-4 S/m to 2 × 10-3 S/m with an increase in graphene from 0 to 8 mg·mL-1. Concurrently, the resistance of the hydrogel with 8 mg·mL-1 graphene increased from 160 kΩ to 485 kΩ with a gauge factor (GF) = 0.02 under 100% strain, while maintaining a good cyclic stability. The results of the sensing and monitoring of finger joint bending revealed a significant shift in the reflective peak of the photoelectric dual-mode sensor from 624 nm to 526 nm. Additionally, its resistance change rate was measured at 1.72 with a 90° bending angle. These findings suggest that the photoelectric dual-mode sensor had the capability to detect the strain signal with photoelectric dual-mode signals, and indicates its great potential for the sensing and monitoring of joint motion.

A Low-Cost Laser Welding Monitoring Framework Based on Depth-Wise Separable Convolution with Photoelectric Signals

A Low-Cost Laser Welding Monitoring Framework Based on Depth-Wise Separable Convolution with Photoelectric Signals

Non-contact intelligent sensor for recognizing transparent and naked-eye indistinguishable materials based on ferroelectric BiFeO3 thin films

At present, the research on ferroelectric photovoltaic materials mainly focuses on photoelectric detection. In the context of the rapid development of the Internet of Things (IoT), it is particularly important to use smaller thin-film devices as sensors. In this work, an indium tin oxide/bismuth ferrite (BFO)/lanthanum nickelate device has been fabricated on an F-doped tin oxide glass substrate using the sol–gel method. The sensor can continuously output photoelectric signals with little environmental impact. Compared to other types of sensors, this photoelectric sensor has an ultra-low response time of 1.25 ms and ultra-high sensitivity. Furthermore, a material recognition system based on a BFO sensor is developed. It can effectively identify eight kinds of materials that are difficult for human eyes to distinguish. This provides new ideas and methods for developing the IoT in material identification.

Ultrasensitive Photoelectrochemical Biosensor for Dual-miRNAs Detection Based on Molecular Logic Gates and Methylene Blue Sensitized ZnO@CdS@Au Nanorods.

The occurrence of cancer is often closely related to multiple tumor markers, so it is important to develop multitarget detection methods. By the proper design of the input signals and logical operations of DNA logic gates, detection and diagnosis of cancer at different stages can be achieved. For example, in the early stages, specific input signals can be designed to correspond to early specific tumor markers, thereby achieving early cancer detection. In the late stage, logic gates for multitarget detection can be designed to simultaneously detect multiple biomarkers to improve diagnostic accuracy and comprehensiveness. In this work, we constructed a dual-target-triggered DNA logic gate for anchoring DNA tetrahedra, where methylene blue was embedded in the DNA tetrahedra to sensitize ZnO@CdS@Au, achieving ultrasensitive detection of the target substance. We tested the response of AND and OR logic gates to the platform. For AND logic gates, the sensing platform only responds when both miRNAs are present. In the concentration range of 10 aM to 10 nM, the photoelectric signal gradually increases with an increase of the target concentration. Subsequently, we used OR logic gates for miRNA detection. Even if only one target exists, the sensing platform exhibits excellent performance. Similarly, within the concentration range of 10 aM to 10 nM, the photoelectric signal gradually increases with an increase of the target concentration. The minimum detection limit is 1.10 aM. Whether it is the need to detect multiple targets simultaneously or only one of them, we can achieve it by selecting the appropriate logic gate. This strategy holds promising application prospects in fields such as biosensing, medical diagnosis, and environmental monitoring.

Mott-Schottky junction mediated photothermal-pyroelectric synergy for effective collection of waste heat in flexible sensing platform

Solar–energy–induced photothermal–pyroelectric synergy sensing platform provides a win-win route to harvest waste heat and convert energy. However, the increase of carrier collision probability from high temperature inevitably leads to the loss of quantum efficiency. Herein, a flexible photothermal-pyroelectric electrode platform with Schottky junction was successfully constructed for maximum utilization of carrier. Under solar-simulated irradiation, the electron-rich and electron-depletion region formed by the Bi13S18Br2-S/alloy rectifier interface in flexible polyvinylidene difluoride-hexafluoropropylene film can increase the accumulation of photogenerated electrons. Meanwhile, the surface bound charges released by dipole oscillation in photothermal-pyroelectric field are continuously supplemented by the emerged high concentration of photogenerated electrons from the Schottky junction, and this synergistic effect prolonged their lifetimes and significantly improves the photoelectric conversion efficiency. To reasonably realize the accurate quantification of the simulated target, the cleavage activity of the CRISPR–Cas system can be specifically restored with the assistance of a synergistic dual-activator, releasing silica as a padlock to produce a target concentration-dependent photoelectric signal. Besides, the temperature variation on the electrode interface was simulated, revealing the synergistic effect between Schottky junction and photothermal–pyroelectric field under photoexcitation. This work broadens a new perspective for upgrading photoelectron utilization and overall performance of flexible sensing platform.

Inverse fitting direct absorption spectroscopy Technology: Simplified implementation and enhanced performance

The conventional direct absorption spectroscopy (DAS) technique has been plagued by the difficulty of obtaining accurate baseline, which is caused by photoelectric drift and the absence of non-absorbing regions in the transmitted light intensity signal. An inverse fitting direct absorption spectroscopy (IF-DAS) technique has been proposed to address this difficulty. The technique leverages the intrinsic nonlinear intensity response of tunable lasers to achieve baseline-free concentration measurements. It offers the advantages of being straightforward to implement, baseline-free, calibration-free, and resistant to photoelectric signal drift. Its efficacy was validated using an example under ambient temperature and atmospheric pressure conditions. The performance of the IF-DAS technique was compared with that of the conventional DAS technique through standard experimental tests. The results demonstrate that the IF-DAS technique is less susceptible to fluctuations in light intensity, exhibits superior linearity and accuracy, with an R2 value of 0.99986 and an overall error of less than 2%. This technique shows potential for application in harsh scenarios such as reactive flow fields and long-term engineering applications.

The Intersection of Plastic Electronics and Medical Innovation

The aging global population has catalyzed a paradigm shift in healthcare, emphasizing disease prevention over treatment and underscoring the need for large-scale, long-term monitoring of physiological parameters. Wearable health monitoring devices have emerged as a pivotal solution, offering real-time physiological data collection across prevention, treatment, and rehabilitation phases, thus revolutionizing traditional health monitoring approaches. This paper explores the integration of advanced materials—conductive polymers, flexible carbon nanomaterial electrodes, and metal foil substrates—into wearable health technologies. These materials enhance device flexibility, biocompatibility, and non-intrusive monitoring capabilities, providing medical-grade data crucial for early diagnosis and treatment guidance. With the wearable device market projected to expand significantly, fueled by the Internet of Things (IoT) and device miniaturization, this study delves into the technological advancements in detection technologies for electrophysiological, physical, biochemical, and photoelectric signals. It also examines the challenges and future directions in wearable health devices, focusing on material innovation, device miniaturization, and the integration of plastic electronics to improve wearability, sustainability, and interactivity. Through systematic analysis, this paper aims to highlight the transformative impact of wearable health technologies on enhancing patient care, facilitating early disease detection, and offering personalized health management solutions.

A novel triboelectric-optical hybrid tactile sensor for human-machine tactile interaction

Tactile interaction is one of the primary modes of human-machine interaction, which requires artificial devices to possess tactile sensing abilities. In recent years, to enrich the tactile information perceived by artificial devices, tactile sensors based on hybrid sensing mechanisms have attracted extensive attention. However, for wearable or flexible artificial devices, the development of tactile sensors with a simple structure and preparation process, low cost and power consumption, and good maintainability and integration remains a tough challenge. Herein, we presented a triboelectric-optical hybrid tactile sensor (TOHTS) with a separable modular structure, comprising two units: a triboelectric unit designed based on the single-electrode triboelectric nanogenerator to receive external tactile stimuli, and a photoelectric unit with a liquid-membrane liquid lens structure and a function of translating the tactile stimuli into a photoelectric signal. Both units exhibit a simple structure, and their parts can be easily cannibalized and replaced. The triboelectric unit can control the on-off behavior of the light source embedded in the photoelectric unit to minimize power consumption and improve tactile response speed, according to its output signal. The photoelectric unit possesses superior electromagnetic interference immunity, making the TOHTS accurately and quantitatively perceive contact force. The sensing performance test results validate the TOHTS’s advantages of a short response time (about 9 ms), strong linearity (R2≈0.9952) in sensing contact force, and excellent durability and stability. Due to the above features, the TOHTS exhibits outstanding practicability in tactile interactive tasks, which is proved by some interactive input experiments, and it will have extensive application prospects for human-machine interactive devices.

Self-powered photoelectric sensors based on hydrogel diodes doped with photoacid

Artificial retina requires photo-sensory units that convert light into electric signals without relying on any external power supply. Recent development on hydrogel diodes paves a new avenue for creating photo-electric signals that can be picked up by human optic nerves. Here, we report a self-powered photoelectric sensor based on hydrogel diodes doped with photoacid, which produces electric signal relying on no external power supply. The photoelectric sensor is self-powered due to the fact that the photoacid-released protons are mobilized under the influence of the built-in electric field in the hydrogel PN junction. The photo-induced open-circuit voltage reaches to 1.6 mV under 50 mW cm−2. We found that the highest electric response occurred when photoacid was presented at the cationic side of the hydrogel PN junction. A prototype consisting 9-element sensor array is prepared, and we have demonstrated its potential for spatially resolved visualization upon light irradiation.

Ternary BiOI/Bi2S3/Au Nanosheet Arrays as a Photoelectrochemical Signal Converter for the Detection of Cardiac Troponin I.

Nanosheet arrays with stable signal output have become promising photoactive materials for photoelectrochemical (PEC) immunosensors. However, an essential concern is the facile recombination of carriers in one-component nanoarrays, which cannot be readily prevented, ultimately resulting in weak photocurrent signals. In this study, an immunosensor using gold nanoparticle-anchored BiOI/Bi2S3 nanosheet arrays (BiOI/Bi2S3/Au) as a signal converter was fabricated for sensitive detection of cardiac troponin I (cTnI). The ternary nanosheet arrays were prepared by a simple method in which Bi2S3 was well-coated on the BiOI surface by in situ growth, whereas the addition of Au further improved the photoelectric conversion efficiency and could link more antibodies. The three-dimensional (3D) ordered sheet-like network array structure and BiOI/Bi2S3/Au ternary nanosheet arrays showed stable and high photoelectric signal output and no significant difference in signals across different batches under visible light excitation. The fabricated immunosensor has a sensitive response to the target detection marker cTnI in a wide linear range of 500 fg/mL to 50 ng/mL, and the detection limit was 32 fg/mL, demonstrating good stability and selectivity. This work not only shows the great application potential of ternary heterojunction arrays in the field of PEC immunosensors but also provides a useful exploration for improving the stability of immunosensors.

Dual-signaling and ultrasensitive detection for PCT based on the photoelectric and electrocatalytic hydrogen evolution signals of Pt/Mo–CoFeS

Few study has been carried out on the construction of immunesensors utilized the photoelectric and catalytic signal of nanomaterial. Here, a dual-signal electrochemical immunosensor was constructed for procalcitonin (PCT) detection based on the excellent photoelectric and hydrogen evolution performance of molybdenum-doped cobalt-iron sulfur nanosheets modified by platinum nanoparticles (Pt/Mo–CoFeS). Due to the electronic structure regulation between Pt and Mo–CoFeS, Pt/Mo–CoFeS exhibits superior photoelectric and hydrogen evolution performance compared to single Mo–CoFeS, which improved the sensitivity of the electrochemical immunosensor. Furthermore, the presence of Pt improves surface area and biocompatibility, achieving more antibodies loading and signal amplification. The linear range of PCT detection are 0.002–20 ng mL−1 and 0.002–50 ng mL−1, the detection limits are 0.0015 and 0.0012 ng mL−1. In addition, this electrochemical immunosensor was applied to the PCT analysis in human serum samples with high recoveries. F-test and t-test show that there is no significant difference in the test results between the HER and photoelectric signals, the mutual verification between above two signals can effectively improve the accuracy of detection result.

A signal amplifying photoelectrochemical immunosensor based on the synergism of Au@CoFe2O4 and CdS/NiCo2O4 for the sensitive detection of neuron-specific enolases

Neuron-specific enolase (NSE), a marker of small cell lung cancer, is over-expressed in patient serum. To reduce the threat of lung cancer to human health and life, a rapid and effective method for the sensitive detection of NSE is necessary. In this study, a sandwich-type photoelectrochemical (PEC) immunosensor for the rapid and sensitive detection of NSE was constructed. To provide a powerful and stable photocurrent signal, the bandgap-matched CdS/NiCo2O4 was used as the substrate material. In addition, Au@CoFe2O4, which can form a step electron transfer mode with NiCo2O4, was proposed for the first time as a second antibody (Ab2) marker to amplify photoelectric signals. The constructed signal-amplified PEC immunosensor showed good linearity in the range of 1 pg/mL − 100 ng/mL with a detection limit as low as 0.24 pg/mL (S/N=3). The constructed PEC immunosensor has shown excellent stability, selectivity, reproducibility, and repeatability. It showed recoveries in the range of 98% − 105% and relative standard deviations (RSD) within 5% in sample analysis. The method proposed in this study is expected to be more widely used in the future for the detection of other disease markers as well as environmental pollutants.

Self-powered photoelectrochemical immunosensing platform for sensitive CEA detection using dual-photoelectrode synergistic signal amplification

Self-powered photoelectrochemical (PEC) sensing, as an emerging sensing mode, can effectively solve the problems such as weak anti-interference ability and poor signal response of individual photoanode or photocathode sensing. In this work, an ITO/Co–CuInS2 photocathode and ITO/WO3@CdS photoanode based self-powered cathodic PEC immunosensor was developed, which integrated dual-photoelectrode to synergistic amplify the signal for highly sensitive and specific detection of carcinoembryonic antigen (CEA). The self-powered PEC sensor could drive electrons transfer through the difference in Fermi levels between the two photoelectrodes without an external bias voltage. The photoanode was introduced to amplify the photoelectric signal, and the photocathode was only designed for the construction of sensing interfaces. The proposed sensor quantitatively determined the target CEA with the detection limit of 0.23 pg/mL and a linear correlation confine of 0.1 pg/mL ∼100 ng/mL. The constructed immunosensing platform exhibited high sensitivity, satisfactory stability and great biological detection selectivity, providing a feasible and effective strategy for the manufacture of new self-powered sensors in high-performance PEC bioanalytical applications.

Model of a Free-Space Optical Communication Line with a Smart Reflector

The article considers a model of a free-space communication line between several closely located points on the terrain that are outside the line of sight. For the rapid deployment of communication lines with a range of up to hundreds of meters, any tall building visible to all callers can be a kind of optical signal repeater. Compared to radio communication channels, an optical communication line has a higher speed of information transmission, is insensitive to electromagnetic interference and is more protected from eavesdropping. To increase the range of the communication line and increase the signal to noise ratio, it is proposed to use a smart reflector based on the mirror of the two-axis scanner, the angular position of which is controlled by the microcontroller. The microcontroller receives information about the angle of incidence of the laser beam on the smart reflector in the form of photoelectric signals. These signals are formed by a position-sensitive photodetector and a lens in front of it. Depending on the angle of incidence of the laser beam, the position of the laser spot focused by the lens on the photodetector changes, and with it, both signals at its output. To facilitate the search of the smart reflector by transceivers, it is suggested to use an LED beacon in it.