Results of an experimental and theoretical study of transient processes in carbon electrochemical transducer elements with a cylindrical channel and with electrodes placed on two parallel plates are presented. A model of the transient process has been developed that qualitatively and quantitatively describes the output characteristics for a set of experimental samples of electrochemical motion sensors. A numerical solution of the model has been implemented for four transducer configurations, differing in the thickness of the dielectric layer on the cathode (30 and 100 μm), the thickness of the sealing gasket (200 and 500 μm), and the hole density (51x51/cm² and 2x51x51/cm²). A batch of electrochemical cell samples with similar geometric parameters was fabricated to validate the model results; configurations ensuring the minimization of the characteristic transient time and the boundaries of model applicability were established. For the studied range of geometric characteristics, the duration of the transient process turns out to be shorter as the thickness of the dielectric layer on the cathode increases and as the hole density increases.

This study aims to demonstrate the feasibility of developing low-frequency, high-sensitivity seismometers based on electrochemical signal conversion principles and cost-effective manufacturing technologies suited for mass production. The paper describes a new technology for fabricating sensitive electrochemical seismometers with carbon electrodes, which relies on precision laser methods to form microelectrodes in the sensing elements. Sensor prototypes were produced using this technology, testing and calibration methods were developed, and their characteristics were studied. Output parameters were evaluated through parallel recording of seismic signals using the test samples alongside reference high-sensitivity accelerometers and low-frequency geophones. Self-noise levels were determined via correlation analysis to isolate uncorrelated signal components. The sensors operate from 1Hz in the low-frequency range, up to 200Hz in the high-frequency range. Their self-noise turned out to be lower than that of leading seismic MEMS sensors and lacks the typical MEMS spectral density increase below 3-5Hz. Compared to electromagnetic geophones, the working bandwidth expands significantly in the low-frequency region. The manufacturing process supports mass production without expensive equipment or labor-intensive assembly and calibration steps. These features suggest broad potential for electrochemical sensors in seismic exploration.

Modern electrochemical seismic sensors operate over a wide frequency range due to molecular-electronic transfer technology. One of the main advantages of this type of sensor is the ability to control sensitivity. Previously, four-electrode and six-electrode cells have been studied. In this letter, we investigate the features of a five-electrode sensor and a method to control its sensitivity. The results showed that we are able to change the sensitivity by more than ten times, which is five times better than that of a six-electrode sensor.

Electrochemical motion sensors are widely used in the creation of seismology devices. The key element of an electrochemical motion sensor is a miniature electrochemical cell with platinum electrodes, the current, in which changes under the action of external mechanical signals. This work explores the possibility of replacing platinum with much cheaper carbon. Two types of configurations of the converting element have been studied, in one of which the electrodes are located on the walls of a narrow channel, in which liquid flows under the influence of an external signal. In the second configuration, electrodes are made on the sides of the plate, and microscopic holes are made in the plate to transfer fluid between the electrodes. Comparison of the sensitivity of sensors with platinum and carbon electrodes showed the similarity of their characteristics, provided that the electrode systems are similar in their geometry.

A technology based on the use of a miniature electrochemical cell as a sensitive element of seismic sensors has found wide application in the creation of devices for studying the Earth's seismicity. This paper presents the results of the development of a technological process that ensures the creation of planar carbon electrode systems with the geometry required for use in molecular-electronic sensors, and also presents experimental data on the measurement of self-noise for the manufactured transductive elements. The voltage operating point when carbon is used as a material for electrodes has been found to shift to higher voltages, and the spectral dependence of self-noise has a character corresponding to convective-type noise

Four-electrode electrochemical cells are widely used for signal conversion in molecular-electronic transfer (MET) motion sensors. The most used ACCA (anode–cathode–cathode–anode) configuration has proven its performance and usefulness for obtaining a superior conversion factor and a wider frequency range over standard geophones at room temperature. However, the MET sensor conversion factor decreases a thousand-fold or more when the temperature drops from room temperature to 233 K. In the design suggested is this paper, a pair of additional gate (G) electrodes has been added outside the standard ACCA cell. An experimental study of the temperature behavior of the resulting G-ACCA-G six-electrode configuration showed that the effects of temperature changes on the cell conversion factor are 5.2 times weaker compared with the standard ACCA configuration.

The paper analyzes the stage of decomposition of the initial seismic data in the methods of wave reversal in time when constructing seismic attributes. Within the framework of the formal approach of mapping the data of one space into the data of a space of a higher dimension, a classification of existing approaches in seismic exploration is given. Identification of the decomposition stage in the seismic data processing workflow makes it possible to highlight the differences in existing approaches to building seismic attributes and predict the future direction of seismic data processing. The concept of vector decomposition, originally used in the RTH method, is introduced. The variety of depth seismic attributes obtained in the RTH method based on vector decomposition allows solving a wide range of problems in the exploration and development of hydrocarbon deposits at a new qualitative level. The RTH method includes, as a special case, the PSDM, AVO, AI methods and is an alternative to the MVA, FWI methods, as well as the method of a velocity model bilding based on fast beam migration algorithms. A close connection between the technique of wavefront time reversal in seismic exploration and analogous time reversal in optics and acoustics is noted. Examples of seismic data processing using vector decompositio to identify zones of natural fracturing in shale oil are given.

In this article, a new design of a hydrophone based on molecular electronic (MET) technology has been developed, in which the idea of compensating for external hydrostatic pressure regardless of its magnitude is implemented therefore, the maximum immersion depth of the devices is limited only by the tightness of the connections. In this paper, modeling of external sensitive elements of the structure is carried out in order to determine the optimal characteristics. The proposed hydrophone designs are capable of detecting ultra-low frequency signals (~ 0.01 Hz), which makes it possible to cover the range of the most interesting signals in seismic. In this design, a linear acceleration compensation system is implemented, which makes it possible to dispense with one sensitive element. Also, in the developed design of the MET-hydrophone, a new type of MET-converter with an electronic circuit 2x2 was used for the first time. The article presents the results of a comparison of the sensitivity study of the developed hydrophone design and a hydrophone not equipped with a linear acceleration compensation system. These results confirm a decrease in the sensitivity of the hydrophone to linear accelerations by more than 1.5 times. There is also the possibility to further reduce the level of sensitivity of the hydrophone to linear accelerations. Prototypes of new MET-hydrophone designs have been developed and manufactured, the main characteristics of the prototypes have been determined, theoretical conclusions about the high absolute sensitivity of the hydrophone, the independence of sensitivity from the magnitude of external hydrostatic pressure, the linear dependence of sensitivity on the thickness of the external sensitive elements of the mechanical system, the linearity of the response of the device to external influences have been experimentally confirmed.

The limits for recording weak signals for electrochemical seismic sensors are determined by their self-noise. At the same time, the noise nature is complex and not fully understood. In this work, for the first time, in addition to the frequency dependences of the noise amplitude, the difference in the phases of the noise currents of the cathodes of an electrochemical sensor has been studied. It has been established that at low frequencies the cathode currents change in an-tiphase. As the frequency increases, the phase difference becomes random. At the same time, the frequency at which the phase difference changes depend on the interelectrode distance; the clos-er the electrodes are located to each other, the greater it is. Physically, this effect is explained by the transition from noise caused by the integral flow of the working fluid to noise associated with vortex flows, the size of which depends on frequency. Thus, a new way of studying noise makes it possible to identify its physical nature and develop new methods of reduction.

This paper proposes a generalized mathematical model of hydrodynamic fluctuations near the electrodes of electrochemical microsystems and mechanisms for converting hydrodynamic fluctuations into electrode current noise. The practical value of the proposed model lies in the creation of detailed models of hydrodynamic fluctuations, which make it possible to reveal the internal structure of noise flows in liquid microsystems and explicitly take into account the influence of the details of the surface geometry that limits the volume of the working fluid.

В статье анализируются современные методы построения сейсмических атрибутов на основе сопряженных уравнений акустики с учетом векторной природы волнового распространения в среде. Показывается, что детальный анализ совместного поведения векторов скорости в прямой волне и в обращенной во времени позволяет решать широкий круг задач нефтеразведки на новом качественном уровне. Приведены примеры обработки сейсмических данных на основе детального анализа обращенного во времени векторного волнового поля. Дан прогноз дальнейшего развития сейсморазведки в этом направлении. The article analyzes modern methods for design seismic attributes based on conjugate acoustic equations, taking into account the vector nature of wave propagation in a medium. It is shown that a detailed analysis of the joint behavior of the velocity vectors in a direct wave and in a time-reversed wave makes it possible to solve a wide range of oil exploration problems at a new qualitative level. Examples of seismic data processing based on a detailed analysis of a time-reversed vector wave field are given. The forecast of further development of seismic exploration in this direction is given.

The paper presents the results of modeling and their verification based on numerous experimental studies of the temperature dependences of the amplitude-frequency characteristics of molecular-electronic sensors as exemplified in a linear displacement sensor. Data on the temperature dependence of the amplitude-frequency characteristic and background currents for a water-alcohol based electrolyte with the addition of low concentrations of potassium iodide have been accumulated and systematized. Various types of conversion nodes have been studied, differing in the conversion area, the number and density of electrode grids. While processing the results, refined models of temperature dependences have been formed, analytical approximating curves have been selected for each family of characteristics, and the activation energies of viscosity and diffusion have been calculated for various physical mechanisms that manifest themselves in the observed experimental patterns.

Broadband organic photodetectors (OPDs) can be integrated into various wearable devices and show great application potential in health monitoring and other fields. Here, we demonstrated high-performance broadband photomultiplication-type OPDs (PM-OPDs) based on MoO3 trapping electron-assisted hole tunneling injection mechanism with small-molecule lead (II) phthalocyanine (PbPc) and C70 fullerene as the donor and acceptor, respectively. In order to control the crystal phase structure formed by PbPc molecules, we prepared PbPc:C70 bulk heterojunction (BHJ) and PbPc/C70 planar heterojunction (PHJ) devices. It can be seen that the PHJ device exhibits stronger near-infrared (NIR) absorption characteristics, which is more conducive to the formation of the triclinic phase structure of the PbPc molecule. We further prepared flat panchromatic PM-OPDs in the range of 300–1000 nm by using materials (PbPc and SubPc) with absorption complementary characteristic as the active layers and PHJ/BHJ hybrid heterojunction structure. The external quantum efficiency of the resulting panchromatic PM-OPDs exceeds 1000% in the whole spectral response range under −8 V reverse bias. Finally, we prepared flexible panchromatic PM-OPDs on polyethylene terephthalate substrate and successfully realized the detection of the human pulse signal. This work provides a new strategy for obtaining high-performance panchromatic PM-OPDs by designing device structures and selecting appropriate materials.

The conversion factor of the electrochemical motion sensors at low frequencies is usually quite high. At the same time, it decreases significantly with the increase in frequency. Thus, increasing the conversion factor for high frequencies is essential for practical use. In this work, the theoretical model that allows establishing the basic laws governing the conversion of high-frequency signals in an electrochemical cell has been suggested. The approach was based on the fact that in the case of high frequencies, the diffusion length is less than the distance between the electrodes and the thickness of the channel and it is enough to consider the transformation of the fluid motion into electrical current only near the cathodes. It was found that the signal output current can be represented as the sum of the term which is proportional to the steady-state concentration gradient along the surface on which the cathode is located, and the term proportional to the concentration gradient normal to the surface. Both first and second terms and the total signal current have been calculated for a particular case of a four-electrode planar system. The practical conclusion is that the high frequency conversion factor increases with the interelectrode distance and the channel width decreases compared to the cathode dimension.

The paper presents modeling of the convective noise produced in a planar sensitive element of electrochemical motion sensors. The electrodes in such a sensitive element are a system of parallel conductive strips placed on a flat surface of a channel where liquid flows under the action of a mechanical disturbance. The theoretical model uses equations of hydrodynamics and active ions transfer in the system. The electrode current noise is calculated in case of the vortex-type stochastic hydrodynamic motion modeled by the Langevin method applied to equations of hydrodynamics. At high frequencies, the solution of the equations has been simplified and the dependence of the noise current on the channel thickness, the distance between the electrodes and the electrodes size have been studied. The modeling results have been compared to the experimental results published earlier

This paper presents the experimental results of studying the samples of the electrochemical sensors of motion parameters on the base of Molecular Electronics Technology (MET). The sensors with microelectromechanical (MEMS) electrode assembly use electrolytes based on aqueous and non-aqueous solutions of potassium and lithium iodides. Electrolyte solutions contain impurities of ionic liquids and alcohols to achieve stable low-temperature operation and acceptable technical parameters of serial devices. The dependence of the general sensitivity and the shape of the amplitude-frequency characteristic on temperature have been studied. For the marginally acceptable samples, which had an acceptable temperature dependence of the conversion coefficient and low activation energies for the diffusion coefficient, the level of self-noise was found. The activation energy of the electrolyte diffusion coefficient was determined based on the analysis of the dependence of the background current on temperature. A conclusion was made regarding the possible prospects for using the studied solutions and components for operation in serial devices.

Low‐cost and flexible panchromatic organic photodetectors (OPDs) are one of the most promising alternatives in next‐generation wearable electronics, but they still face the formidable challenges of replacing brittle indium tin oxide electrode and suffer from low near‐infrared (NIR) photo‐response. Herein, the low‐cost metal copper (Cu) is used as a semi‐transparent anode to fabricate high‐performance panchromatic multiplication‐type OPDs. Because of the advantages of smooth surface, lower sheet resistance, and good transmittance, high‐quality optical resonant cavity forming between Cu anode and aluminum cathode greatly enhanced the weak sub‐bandgap response of intermolecular charge transfer states in NIR region, while also retaining a good response in the UV–vis region. Due to the good hole‐collecting ability, the Cu electrode is suitable for realizing the photo‐multiplication effect. Accordingly, the resulting OPDs achieve a panchromatic response ranging from the UV (300 nm) to NIR (900 nm) region. The maximum external quantum efficiency (EQE) reaches 117 040% at 350 nm, and the relatively high EQE of 25 468% is realized even at 765 nm. Furthermore, a flexible OPD is successfully fabricated by using polyethylene terephthalate substrate with Cu anode to achieve the real‐time detection of human blood oxygen pulse signals.

Electrochemical angular micro-accelerometers based on miniaturized planar electrodes positioned in parallel were reported in this paper. Based on liquid inertial masses, incoming angular acceleration was translated into varied concentrations of reactive ions around sensitive electrodes, generating detection currents. As to the sensitive unit configuration, two electrode setups of A(anode) C(cathode)CA-ACCA and ACAC-CACA were utilized in this study for comparison where corresponding key geometrical parameters were optimized based on numerical simulations. Based on microfabrication, electrochemical angular micro-accelerometers with geometrical variations were fabricated and characterized, producing consistent results with numerical simulations and therefore optimized geometrical parameters of electrode space, electrode width and electrode gap were determined. Furthermore, for each electrode setup with optimized geometries, six electrochemical angular micro-accelerometers were characterized, producing high sensitivities with low coefficients of variation, which were 20.169 ± 0.843 V/(rad/s 2 ) for ACCA-ACCA and 5.868 ± 0.328 V/(rad/s 2 ) for ACAC-CACA at 0.01 Hz. In summary, the electrochemical angular micro-accelerometers reported in this study can provide new perspectives for the monitoring of angular vibrations in seismology.

A visible-blind ultraviolet (UV) photodetector can detect UV signals and is not interfered with by visible light or infrared light in the environment. In order to realize high-performance visible-blind UV organic photodetectors (OPDs), we design photomultiplication-type (PM-type) OPDs by using a novel strategy. Firstly, wide bandgap organic semiconductor materials, which do not absorb visible light, are selected as donors to absorb UV light. Secondly, a very small amount of C60 is used as an acceptor to trap photogenerated electrons. These accumulating electrons near the Al electrode form a potential, which leads to band bending and narrowing of the interface barrier, thereby assisting hole-tunneling injection to form a multiplication. The fabricated visible-blind UV PM-type OPDs with donor/acceptor doping ratio of 50 : 1 exhibit a narrowband response with full-width at half-maximum (FWHM) of approximately 36 nm, an ultrahigh external quantum efficiency of 1.08 × 106% and a remarkable specific detectivity of 1.28 × 1014 jones at 335 nm wavelength under -14 V bias. The UV-to-visible rejection ratio exceeds 103 by adjusting the donor/acceptor mixing ratios. The devices made with other wide bandgap organic materials also showed similar performance, indicating that this device structure provides an effective method for the preparation of high-performance visible-blind UV PM-type OPDs. In addition, we prepared a flexible visible-blind UV PM-type OPD based on a PET substrate and integrated it with a flexible OLED to fabricate a wearable UV monitor, which can visually detect the intensity of UV light.

This paper presents a MEMS based electrochemical angular accelerometer with feedback where the relative movement between the liquid inertial mass and the sensitive microelectrodes was counter balanced by the feedback force. Theoretical analysis was conducted to model the response of the angular accelerometer with feedback. Both sensitive and feedback electrodes were made based on microfabrication and assembled to form MEMS based electrochemical angular accelerometer with feedback. Device characterization was conducted, locating a sensitivity of 8 V/(rad/s2), a bandwidth of 0.0083-8 Hz and a noise level of $6.31\times 10 ^{-7}$ (rad/ $\text{s}^{2})/\surd $ Hz. In comparison to previously reported MEMS based electrochemical angular accelerometer without feedback, a significant improvement at low frequencies in 3dB bandwidth (0.0083-8 Hz vs. 0.02-10 Hz) was achieved due to the inclusion of the feedback part. This study can provide a new perspective for the development of electrochemical angular accelerometer, which may be further used in seismic monitoring.