Kuzin, Aleksei Yu

Vlasov V.I., Kuzin A.Y., Florya I.N., Buriak N.S., Chernyshev V.S., Golikov A.D., Krasnov L.V., Mikhailov S.E., Pugach M.A., Nasibulin A.G., An P.P., Kovalyuk V.V., Goltsman G.N., Gorin D.A.

Zaytsev V., Kuzin A., Panda K., Chernyshev V., Florya I., Fedorov F.S., Kovalyuk V., Golikov A., An P.P., Khlebstov B.N., Chetyrkina M., Nasibulin A.G., Goltsman G., Gorin D.A.

The microfluidic approach enables both to assemble the structured silica monolayer patterns atop the photonic integrated chips and apply them as optical gas sensors.

Mujtaba J., Kuzin A., Chen G., Zhu F., Fedorov F.S., Mohan B., Huang G., Tolstoy V., Kovalyuk V., Goltsman G.N., Gorin D.A., Nasibulin A.G., Zhao S., Solovev A.A., Mei Y.

AbstractCatalytic valveless micropumps, and membraneless fuel cells are the class of devices that utilize the decomposition of hydrogen peroxide (H2O2) into water and oxygen. Nonetheless, a significant obstacle that endures within the discipline pertains to the pragmatic open circuit potential (OCP) of hydrogen peroxide FCs (H2O2 FCs), which fails to meet the theoretical OCP. Additionally, bubble formation significantly contributes to this disparity, as it disrupts the electrolyte's uniformity and interferes with reaction dynamics. In addition, issues such as catalyst degradation and poor kinetics can impact the overall cell efficiency. The development of high‐performance H2O2‐FCs necessitates the incorporation of selective electrocatalysts with a high surface area. However, porous micro‐structures of the electrode impedes the transport of fuel and the removal of reaction byproducts, thereby hindering the attainment of technologically significant rates. To address these challenges, including bubble formation, the review highlights the potential of integrating electrokinetic and bubble‐driven micropumps. An alternative approach involves the spatiotemporal separation of fuel and oxidizer through the use of laminar flow‐based fuel cell (LFFC). The present review addresses multifaceted challenges of H2O2‐powered FCs, and proposes integration of electrokinetic and bubble‐driven micropumps, emphasizing the critical role of bubble management in improving H2O2 FC performance.

Kovalyuk V.V., Venediktov I.O., Sedykh K.O., Svyatodukh S.S., Hydyrova S., Moiseev K.M., Florya I.N., Prokhodtsov A.I., Galanova V.S., Kobtsev D.M., Kuzin A.Y., Golikov A.D., Goltsman G.N.

We consider superconducting single-photon detectors, which are the key element of quantum optical technologies due to their unique characteristics not available in other technologies today. Since the first demonstration in Russia in 2001, such detectors have evolved significantly, and their waveguide-based versions are ready for scaling both in the fields of classical technologies (attenuated light) and of quantum optical applications (non-classical light). The paper studies the operating principle of such detectors and their main characteristics, analyzes superconducting materials and dielectric waveguide platforms, highlights the design principles, considers various levels of integration of on-chip waveguide superconductor detectors, and presents important new areas of application towards the implementation of photonic and ion quantum processors, as well as energy-efficient neuromorphic computing.

Tolstoy V., Nikitin K., Kuzin A., Zhu F., Li X., Goltsman G., Gorin D., Huang G., Solovev A., Mei Y.

In this study, Pt(0) microscrolls are synthesized on polished Ni via Galvanic Replacement Reaction (GRR). Employing in situ optical microscopy, the dynamic motion of catalytic microscrolls as micromotors in H2O2...

Kuzin A., Panda K., Chernyshev V., Florya I., Kovalyuk V., An P., Golikov A., Chulkova G., Kolesov D., Gorin D., Goltsman G.

Photonic biosensors based on photonic integrated circuits (PICs) and microfluidic channels (MFCs) have become the subject of intensive research for point-of-care (POC) device applications. In the presented work, we demonstrate the possibility of identifying the complex refractive index (RI) of analyzed liquids through the optimization of the geometry configuration of MFCs under PICs by experimental and numerical approaches. Our results suggest that the real and imaginary parts of the RI for analytes under study can be determined from spectrum of devices with optimized MFCs width. This work paves the way for promising opportunities to identify the presence and concentration of biological markers by using RI sensors for in situ POC applications.

Kuzin A., Chernyshev V., Kovalyuk V., An P., Golikov A., Svyatodukh S., Perevoschikov S., Florya I., Schulga A., Deyev S., Goltsman G., Gorin D.

Today, the search for disease biomarkers and techniques for their detection is one of the most important focuses in modern healthcare. Extracellular vesicles (EVs) are known to be related to the pathogenesis of various illnesses, such as cancer, neurodegenerative disease, and cardiovascular disease. Specific EV detection and potential control of their amount in biological fluids can provide a promising therapeutic strategy that involves reduction in EV production and circulation to normal levels to prevent disease progression. To provide a foundation for such research and development, we report the application of photonic integrated circuits in the form of a Mach–Zehnder interferometer coupled with microfluidics for monitoring each step of a covalent linkage between receptors and silicon nitride. We show that such a biosensor can be used for biological marker quantification, such as EVs containing a specific membrane protein HER2. The developed platform provides real-time results by using microliter volumes of the test sample. This research can be used as a first step toward creation of a laboratory on a chip for the precise control of coating in terms of chemical applications and monitoring the effectiveness of the chosen treatment for medical applications.

Zhu F., Chen G., Kuzin A., Gorin D.A., Mohan B., Huang G., Mei Y., Solovev A.A.

Zhu F., Kuzin A., Chen G., Gorin D.A., Mohan B., Huang G., Zhao S., Mei Y., Solovev A.A.

Kuzin A., Chen G., Zhu F., Gorin D., Mohan B., Choudhury U., Cui J., Modi K.M., Huang G., Mei Y., Solovev A.A.

The emergence of "nanomotors," nanomachines," and "nanorobotics" has transformed dynamic nanoparticle research, driving a transition from passive to active, intelligent nanoscale systems. This review examines two critical fields: the investigation...

Kuzin A., Fradkin I., Chernyshev V., Kovalyuk V., An P., Golikov A., Florya I., Gippius N., Gorin D., Goltsman G.

Spectrometers are widely used tools in chemical and biological sensing, material analysis, and light source characterization. However, an important characteristic of traditional spectrometers for biomedical applications is stable operation. It can be achieved due to high fabrication control during the development and stabilization of temperature and polarization of optical radiation during measurements. Temperature and polarization stabilization can be achieved through on-chip technology, and in turn robustness against fabrication imperfections through sensor design. Here, for the first time, we introduce a robust sensor based on a combination of nanophotonic random spectrometer and microfluidics (NRSM) for determining ultra-low concentrations of analyte in a solution. In order to study the sensor, we measure and analyze the spectra of different isopropanol solutions of known refractive indexes. Simple correlation analysis shows that the measured spectra shift with a tiny variation of the ambient liquid optical properties reaches a sensitivity of approximately 61.8 ± 2.3 nm/RIU. Robustness against fabrication imperfections leads to great scalability on a chip and the ability to operate in a huge spectral range from VIS to mid-IR. NRSM optical sensors are very promising for fast and efficient functionalization in the field of selective capture fluorescence-free oncological disease for liquid/gas biopsy in on-chip theranostics applications.

Kuzin A., Chernyshev V., Kovalyuk V., An P., Golikov A., Goltsman G., Gorin D.

An elaboration of the photonic based sensors is the most promising direction in modern analytical chemistry from the point of view of real clinical applications. The highest sensitivity is demonstrated by sensors based on photonic integrated circuits (PICs). This type of sensor has been recently successfully combined with microfluidics, which decreased the analyte volume for analysis down to microliter units. The most significant disadvantage regarding these photonic sensors is low specificity. One of the methods that could be useful for such type of problem is the layer by layer (LBL) assembly. The peculiarity of a PIC based sensor is the ability to precisely control surface modification by using measurements of a minimum resonance position shift. The bovine serum albumin (BSA) and tannic acid (TA) molecules were selected for LBL assembly because on one side they form a stable LBL assembly film based on hydrogen bonds, while the other side of both TA and BSA molecules can be used for conjugation with target molecules. A microring resonator (MRR) and a Mach-Zehnder interferometer (MZI) based on a silicon nitride platform combined with a microfluidic system were elaborated and used for monitoring the LBL film assembly. Obtained results have a good correlation with measurements carried out by atom force microscopy. Thus, the ability of using PIC based sensors for in situ control of surface modification was demonstrated and can be considered in point-of-care (POC) devices that have a very good perspective for both early pathological state diagnosis and evaluation of treatment efficiency.

Kuzin A., Chernyshev V., Kovalyuk V., An P., Golikov A., Ozhegov R., Gorin D., Gippius N., Goltsman G.

Today, a lab-on-a-chip is one of the most promising ways to create sensor devices for gas and liquid analysis for environmental monitoring, early diagnosis, and treatment effectiveness assessment. On the one hand, this requires a large number of measurements and, on the other hand, involves minimum consumption of the test analytes. Combination of highly sensitive photonic integrated circuits (PICs) with microfluidic channels (MFCs) is necessary to solve this problem. In this work, PICs based on a silicon nitride platform integrated with MFCs for studying liquids and gases were developed. Different concentrations of isopropanol in de-ionized water were used as the analyte. Based on this, the sensitivity (S) and detection limit (DL) of the analyzed solution were evaluated. Entire system calibration was carried out to calculate S and DL, considering experimental and numerical simulation data. This development may be of interest as a promising platform for environmental monitoring and realization of point-of-care strategy for biomedical applications.

Kuzin A.Y., Elmanov I.A., Elmanova A.V., An P.P., Kovalyuk V.V., Goltsman G.N.

Elmanova A., Elmanov I., An P., Kovalyuk V., Kuzin A., Golikov A., Goltsman G.

Abstract In this work we studied how focusing grating couplers, developed for telecommunication C-band wavelength range, can be applied in the near infrared range. In the paper we presented prospects of usage of both first and second diffraction maxima of theoretically computed diffraction grating couplers for photonic aims. The dependence of the central wavelength of the grating on the etching depth of the photonic layer, on the period and filling factor of the grating was studied. We have compared our experimental results with numerical study, performed using finite elements method of solving differential equations. The work is important for different photonic applications and introduces new prospects in application of the already fabricated devices, developed for telecommunication wavelengths.

Hamza M.N., Islam M.T., Lavadiya S., Din I.U., Sanches B., Koziel S., Naqvi S.I., Panda A., Alibakhshikenari M., Virdee B., Islam M.S.

Liu C., Ding R., Yin X.

The stability of electrocatalysts in acidic solutions containing H2O2 is crucial for the large-scale application of innovative electrochemical devices utilizing H2O2 electrocatalytic reactions for energy conversion and storage. Herein, we investigate the stability of Pt/C catalysts for the H2O2 oxidation reaction (HPOR), examining the evolution of their structure and electrochemical properties. During stability testing, we found that Pt/C catalysts exhibit great activity retention despite a loss of electrochemical active area (ECA) caused by particle coarsening. The increase in Pt particle size is attributed to the H2O2-promoted formation of PtOH, followed by its electrochemical dissolution and redeposition at the HPOR potential. Remarkably, both specific activity and intrinsic kinetic activity for the HPOR increase with the Pt particle size. The enhanced intrinsic activities of larger Pt particles offset the ECA loss during long-term operation, revealing a self-compensating effect. These findings highlight Pt/C as a promising electrocatalyst for H2O2-related electrochemical devices.

Vlasov V.I., Kuzin A.Y., Florya I.N., Buriak N.S., Chernyshev V.S., Golikov A.D., Krasnov L.V., Mikhailov S.E., Pugach M.A., Nasibulin A.G., An P.P., Kovalyuk V.V., Goltsman G.N., Gorin D.A.

Zhu M., Fu X., Yang H., Song Q., Wang H., Ma S.

We propose a microfluidic device that incorporates two layers of planar split-ring resonator (SRR)-based terahertz (THz) metamaterials and study its optical performance through simulation. The device features a concise design and leverages mature and straightforward fabrication processes. Our simulations reveal its remarkable sensing capabilities, with a sensitivity of up to 507.7 GHz/RIU for refractive index (RI) sensing and 16.03 GHz/μm for pressure sensing. Moreover, the device enables real-time monitoring, as it allows for a continuous flow of liquid between the layers. It can also function as an optical switch with a straightforward controlling method involving injecting and evacuating liquid. The maximum modulation depth (MD) achieved is 64.5%. The influence of fabrication errors during assembly of the two layers was studied in detail through simulation. The device demonstrates great robustness against fabrication imperfections, such as layer misalignment and spacer thickness variations, for most of the applications. Strict alignment is only necessary when targeting high-sensitivity RI sensing using the second resonance. The device’s unique combination of sensitivity, tunability, and compact design paves the way for potential applications in diverse fields, including biosensing, environmental monitoring, and optical communications.

Alderson F., Appuhamy R., Gadsden S.A.

Hydrogen peroxide is a promising alternative to hydrogen gas for fuel cells, as it can act as the oxidizing and reducing agent and be stored in a stable liquid form, it simplifies the structure of the fuel cell. This study aims to investigate the use of antimony, bismuth, indium, tantalum, silver, dysprosium, erbium, gadolinium, holmium, and terbium as electrodes for the first time in a single-compartment hydrogen peroxide fuel cell. In this study, the procedure for custom electrodes for these metals is documented. The performance of the electrodes was evaluated by measuring the open circuit potential, comparing the cyclic voltammograms and observing the physical reactions of the cell combinations. The results of the study show the catalytic reaction is likely due to the formation of molecular oxide layers on the electrode surface. It was evident that an acidic peroxide electrolyte favors the best catalytic reaction. Tantalum and antimony were found to be the best-performing electrodes in this electrolyte, providing the best stability and performance.

Letchumanan I., Mohamad Yunus R., Mastar@Masdar M.S., Karim N.A.

This comprehensive review explores recent advancements in electrocatalyst architecture to enhance the oxygen reduction reaction (ORR) in anion exchange membrane fuel cells (AEMFCs). It examines strategies such as nanostructuring, alloying, and heteroatom doping to improve catalytic activity, stability, and durability properties. Key findings reveal the importance of optimizing catalyst morphology, composition, and interface engineering to mitigate challenges such as sluggish kinetics and electrode degradation. Additionally, insights into mechanistic aspects and performance metrics are discussed, highlighting the crucial role of electrocatalysts in advancing AEMFC technology. Overall, this review provides valuable perspectives for researchers and engineers in designing efficient and durable electrocatalysts for next-generation AEMFCs, thereby facilitating the transition towards sustainable energy solutions.

Wang Y., Zhou N., Yu P., Lu H., Miao L., Chen X., Sun D.

Fukuzumi S., Lee Y., Nam W.

AbstractPhotoredox catalysis has attracted increasing attention because of wide range of synthetic transformations and solar energy conversion applications. Reviews on photoredox catalysis have so far focused predominantly on the synthetic applications. This review highlights how organic photoredox catalysts were developed and how they function as efficient photocatalysts in mechanistic point of views. In particular, 9‐mesityl‐10‐methylactidinium (Acr+–Mes) has been highlighted as one of the best organic photoredox catalysts. Acr+–Mes was originally developed as a model compound of the photosynthetic reaction center to mimic the long lifetime of the charge‐separated state in which the energy is converted to chemical energy in photosynthesis. The reason why Acr+–Mes acts as one of the most efficient photoredox catalyst is clarified in terms of the one‐electron redox potentials and long lifetimes of the electron‐transfer state (Acr•–Mes•+) produced upon photoexcitation of Acr+–Mes in different solvents. The reason why the mesityl substituent at the 9‐position of the Acr+ moiety is essential for the efficient photoredox catalysis is discussed in comparison with acridinium ions with different substituents R (Acr+–R) including 10‐methylacridinium ion with no substituent (AcrH+). The mechanisms of photoredox catalysis of Acr+–Mes are discussed in various synthetic transformations and solar energy conversion reactions mimicking photosynthesis. Photoredox catalysis of quinolinium ion and its derivatives is also discussed in comparison with that of Acr+–Mes. Finally, immobilization of Acr+–Mes and quinolinium ions to form the composite catalysts with redox catalyst is discussed to improve the photoredox catalytic activity and stability.

Song J., Liu X., Xie H., Wang Y., Gan Z., Chen Z.

Wang K., Bi C., Zelenkov L., Liu X., Song M., Wang W., Makarov S., Yin W.

Sokolovskij E., Kilikevičius A., Chlebnikovas A., Matijošius J., Vainorius D.

The removal of particulate matter (PM) from air streams is essential for advancing environmental technologies and safeguarding public health. This study explores the performance of an electrostatic precipitator (ESP) in eliminating fine and ultra-fine PM under varied experimental conditions. It uniquely examines the influence of PM size and feed rate on ESP removal efficiency. The system’s use of low voltages enhances energy sustainability, while its innovative design improves corona discharge, leading to significant reductions in fine and ultra-fine PM emissions. Plants using electrical devices are increasingly being incorporated into material processing lines to reduce pollution in the surrounding work area, as well as to collect particle emissions in the atmosphere. It is also possible to recycle some raw materials in this way with low energy consumption. This cleaning technology increases the added value of industrial equipment, which affects its competitiveness and its impact on sustainable manufacturing. The experimental results indicate a steady electrostatic field voltage of 15.1 kilovolts, with an airflow maintained at 0.8 m/s through a doser at 2.5 bar, eliminating the need for a fan. The PM feed rate varied between 2 and 20 mm/h, with six trials conducted to ensure the data were consistent. Preliminary studies devoid of ESP intervention demonstrated little PM removal, since buildup on the chamber walls distorted the results. The installation of the ESF markedly enhanced the removal efficiency, achieving up to 95.5%. Further analysis revealed that ESP performance depended on PM concentration in the agglomeration chamber, achieving a clearance rate exceeding 98% under optimal conditions. Fine PM (0.35 to 8.7 µm) was more efficiently removed than ultra-fine PM (0.2 to 0.35 µm). The highest removal efficiency was observed at a feed rate of 0.962 mg/s, while the lowest occurred at 0.385 mg/s. A strong positive correlation between particle concentration and removal efficiency (Pearson value up to 0.829) was observed, particularly at feed rates of 0.128, 0.641, and 1.283 mg/s. The study’s findings confirm that the ESP is highly effective in removing particulate matter, particularly fine and ultra-fine particles, with an optimal feed rate, significantly enhancing the system’s performance.

Neilo A., Bakurskiy S., Klenov N., Soloviev I., Stolyarov V., Kupriyanov M.

The supercurrent in a Josephson SF1S1F2sIS spin valve (“S” is for superconductor, “F” is for ferromagnet, and “I” is for insulator) is studied theoretically. It is found that by rotating the magnetization of one of the ferromagnetic layers, a smooth switching of the system between two states with different critical currents is possible. The operating range of the device can be adjusted by varying the thickness of the intermediate s-layer. The proposed structure is a promising scalable control element for the use in superconducting electronics.

Zaytsev V., Kuzin A., Panda K., Chernyshev V., Florya I., Fedorov F.S., Kovalyuk V., Golikov A., An P.P., Khlebstov B.N., Chetyrkina M., Nasibulin A.G., Goltsman G., Gorin D.A.

The microfluidic approach enables both to assemble the structured silica monolayer patterns atop the photonic integrated chips and apply them as optical gas sensors.

Liu J., Zhuang R., Zhou D., Chang X., Li L.

Abstract Micro/nanorobots (MNRs) capable of performing tasks at the micro- and nanoscale hold great promise for applications in cutting-edge fields such as biomedical engineering, environmental engineering, and microfabrication. To cope with the intricate and dynamic environments encountered in practical applications, the development of high performance MNRs are crucial. They have evolved from single-material, single-function, and simple structure to multi-material, multi-function, and complex structure. However, the design and manufacturing of high performance MNRs with complex multi-material three-dimensional structures at the micro- and nanoscale pose significant challenges that cannot be addressed by conventional serial design strategies and single-process manufacturing methods. The material-interface-structure-function/ performance coupled design methods and the additive/formative/subtractive composite manufacturing methods offer the opportunity to design and manufacture MNRs with multi-materials and complex structures under multi-factor coupling, thus paving the way for the development of high performance MNRs. In this paper, we take the three core capabilities of MNRs—mobility, controllability, and load capability—as the focal point, emphasizing the coupled design methods oriented towards their function/performance and the composite manufacturing methods for their functional structures. The limitations of current investigation are also discussed, and our envisioned future directions for design and manufacture of MNRs are shared. We hope that this review will provide a framework template for the design and manufacture of high performance MNRs, serving as a roadmap for researchers interested in this area.

Ye H., Wan B., Zhao Y., Li B., Zhang H.

In this paper, using the electric field regulation and low loss properties of liquid crystal materials, a tunable polarization-separated liquid crystal (LC) topological edge state is proposed, whose potential in responsive sensors (RSs) is explored. Adjustment of the measuring range and sensitivity of the RS can be realized by controlling the orientation angle of LC and the analyte proportion. In the case of a low ratio of analytes, as the LC orientation angle changes from 18° to 0°, the measurement range will also vary from 1–1.8 RIU (refractive index unit) to 1.8–2.3 RIU. When adding the proportion of analytes and the number of periods, the normalized sensitivity will be increased from 0.0759 c/d/RIU (c is the propagation speed of light in vacuum, and d is the normalized thickness) to 0.299 c/d/RIU, leading to a reduction in the detection limit from 2.75 × 10−4 to 5 × 10−6 RIU, so biological indicators such as bacteria Leptospira in rodent urine can be detected.

Zhu H., Yin C., Lu M., Li Z., Ma Q., Su H., Yang W., Xu Q.

Loktionov P., Pustovalova A., Pichugov R., Konev D., Antipov A.

In this work, we aimed to reveal two main contributors to the capacity fade of a vanadium redox flow battery (VRFB). These contributors are the oxidative imbalance caused by the hydrogen evolution reaction (HER) competing with V3+ reduction during charging, and crossover, particularly the net transfer of vanadium ions from negolyte to posolyte. To investigate this, we performed VRFB cycling under various operation conditions with sequential monitoring of the electrolytes composition. We discovered that shortly after cycling starts, the crossover makes the negolyte capacity-limiting. This leads to high polarization of the negative electrode inducing HER and increasing average oxidation state (AOS) of the electrolyte. Our examination shows that the magnitude of the oxidative imbalance correlates with that of the crossover, both being dependent on the state-of-charge (SoC). Therefore, by changing operation conditions, we can slightly influence the crossover, while dramatically affect the oxidative imbalance. We also found that the resulting magnitude of the capacity fade is a trade-off between these two side-processes. This necessitates careful optimization of the battery and electrolyte composition, along with its cycling regime. From the data obtained, we conclude that the only proper approach to achieve lower capacity fade is by ensuring that the negolyte is capacity-limiting over long-term cycling. We hope that the data on the capacity fade mechanisms presented here will facilitate development of more stable and cost-effective VRFBs.

Clemente A., Montiel M., Barreras F., Lozano A., Escachx B., Costa-Castelló R.

This study presents an online algorithm capable to simultaneously estimate the state of charge and state of health of a vanadium redox flow battery. Starting from a general electrochemical model, some order reductions are carried out considering different conservation laws. Based on these low-order models, the observer is designed considering the terminal voltage of the battery. This observer is firstly analyzed using numerical tools. Secondly, an experimental validation is carried out with real data provided by a vanadium redox flow battery stack, consisting on current and voltage measurements.

Dhanda N., Panday Y.K., Kumar S.

Hydrogen peroxide (H2O2) is an innovative and environmentally friendly oxidant that finds wide-ranging applications across multiple industries. In the past, H2O2 production predominantly relied on the anthraquinone method, which had drawbacks such as the generation of organic waste and the requirement for energy-intensive reactions. A cheap, efficient, and sustainable way of producing H2O2 may be achieved through the redox reaction between oxygen and water. On both small and large scales, the electrosynthesis of H2O2 is practical and affordable. In recent years, it has been thought that the energy-intensive anthraquinone process may be replaced by the electrochemical synthesis of H2O2 via the two-electron oxygen reduction reaction (ORR) route. To eliminate the organic pollutants found in drinking water and industrial effluent, highly effective hydrogen peroxide (H2O2) must be produced electrochemically using gas diffusion electrodes (GDEs). Compared to other carbonaceous cathodes, the GDEs as cathodic electrocatalysts demonstrate greater cost-effectiveness, lower energy consumption, and higher oxygen utilization efficiency for the formation of H2O2. A promising alternative for enabling the growth of sustainable economics in the W&W sector is microbial electrochemical systems (MESs) that create H2O2. To enhance the efficiency and predictability of H2O2 production in MESs, a machine-learning approach was adopted, incorporating a meta-learning methodology to forecast the generation rate of H2O2 in MES based on the seven input variables, comprising several design and operational parameters.

Kuzin A., Panda K., Chernyshev V., Florya I., Kovalyuk V., An P., Golikov A., Chulkova G., Kolesov D., Gorin D., Goltsman G.

Photonic biosensors based on photonic integrated circuits (PICs) and microfluidic channels (MFCs) have become the subject of intensive research for point-of-care (POC) device applications. In the presented work, we demonstrate the possibility of identifying the complex refractive index (RI) of analyzed liquids through the optimization of the geometry configuration of MFCs under PICs by experimental and numerical approaches. Our results suggest that the real and imaginary parts of the RI for analytes under study can be determined from spectrum of devices with optimized MFCs width. This work paves the way for promising opportunities to identify the presence and concentration of biological markers by using RI sensors for in situ POC applications.

Kumar K P., Deepthi Jayan K., Sharma P., Alruqi M.

Recent research has extensively focused on 2D materials such as graphene oxide (GO) and MXene due to their intriguing properties, significantly advancing nanotechnology and materials research. This experimental study explores the use of a vanadium electrolyte-based hybrid nanofluid (HNF) composed of GO and MXene (90:10) to enhance vanadium redox flow batteries (VRFBs). The synthesis and characterization of GO and Mxene nanoparticles (NPs) were conducted using various techniques. The HNF, produced at different weight concentrations, underwent analysis for stability, rheology, thermal conductivity (TC), and electrical conductivity (EC) within a temperature range of 10–45 °C. The results indicate that the HNF exhibits favorable stability and Newtonian behavior in the specified temperature range. At 45 °C, the HNF achieves a maximum enhancement of 20.5 % in EC and 6.81 % in TC for 0.1 wt% compared to the vanadium electrolyte. Subsequently, a prognostic model was developed using an explainable ensemble LSBoost-based machine learning approach, employing a test dataset and applying 5-fold cross-validation to prevent overfitting. Hyperparameter optimization was achieved using the Bayesian technique. The LSBoost-based prognostic models created for TC, EC, and viscosity (VST) demonstrated high effectiveness, with R2 values of 0.9981, 0.99, and 0.9954, respectively. The prediction errors were minimal, with RMSE values of 0.00089255, 5.553, and 0.09391 for the TC, EC, and VST models, respectively. Similarly, the MAE values were low, at 0.00068948, 4.0919, and 0.06129.

Hong Y.H., Lee Y., Nam W., Fukuzumi S.

Because hydrogen (H2) is an explosive gas and the volumetric energy density is quite low, it is highly desired to develop liquid or solid solar fuels as safe hydrogen storage...

Bureš M., Götz D., Charvát J., Svoboda M., Pocedič J., Kosek J., Zubov A., Mazúr P.

Vanadium redox flow battery (VRFB) is a potential electrochemical energy storage solution for residential accumulation and grid stabilization. Long-term durability, non-flammability and high overall efficiency represent the main advantages of the technology. The ion-exchange membrane, an essential component of the battery stack, is largely responsible for the efficiency of the battery and capacity losses caused by asymmetric cross-over of vanadium ions and a solvent. To mitigate these losses, we developed a mathematical model of the VRFB single-cell for both cation-exchange membrane (CEM) and anion-exchange membrane (AEM) and validated it against our own experimental data. Our model simulates the charge-discharge cycling of a VRFB single-cell under selected sets of operating conditions differing in the following parameters: applied current density, initial volume and concentration of electrolytes, arrangement of storage tanks (hydraulic shunt) and option of periodic rebalancing of electrolytes. The model includes a description of vanadium ions permeation and osmotic flux across the membrane and kinetics of electrode reactions. The hydraulic connection of electrolyte tanks appears to be the most promising mitigating strategy, reducing capacity losses by 69 % over 150 cycles when compared to standard VRFB set-up, which we have also confirmed experimentally. Moreover, by combining the operation methods, our model shows that using AEM with the hydraulic electrolyte connection and periodic rebalancing, the overall battery utilization can be increased by 80 % compared to a standard operation of VRFB using CEM. The developed model offers useful optimization tool for the construction and operation of flow batteries and can be easily adapted for other chemistries.

Kuzin A., Chernyshev V., Kovalyuk V., An P., Golikov A., Svyatodukh S., Perevoschikov S., Florya I., Schulga A., Deyev S., Goltsman G., Gorin D.

Today, the search for disease biomarkers and techniques for their detection is one of the most important focuses in modern healthcare. Extracellular vesicles (EVs) are known to be related to the pathogenesis of various illnesses, such as cancer, neurodegenerative disease, and cardiovascular disease. Specific EV detection and potential control of their amount in biological fluids can provide a promising therapeutic strategy that involves reduction in EV production and circulation to normal levels to prevent disease progression. To provide a foundation for such research and development, we report the application of photonic integrated circuits in the form of a Mach–Zehnder interferometer coupled with microfluidics for monitoring each step of a covalent linkage between receptors and silicon nitride. We show that such a biosensor can be used for biological marker quantification, such as EVs containing a specific membrane protein HER2. The developed platform provides real-time results by using microliter volumes of the test sample. This research can be used as a first step toward creation of a laboratory on a chip for the precise control of coating in terms of chemical applications and monitoring the effectiveness of the chosen treatment for medical applications.

Vlasov V.I., Pugach M.A., Kopylova D.S., Novikov A.V., Gvozdik N.A., Mkrtchyan A.A., Davletkhanov A.I., Gladush Y.G., Ibanez F.M., Gorin D.A., Stevenson K.J.

In this paper we propose a new method for monitoring of electrolyte's State of Health (SoH) in Vanadium Redox Flow Batteries. The keystone of our approach is a correlation between optical and electrochemical properties of electrolytes based on the shift of electrolytes reflective index (RI) values at the same open circuit voltage (OCV) and their relation to the SoH change. In addition, we propose a simple sensor for RI measurements that can be easily implemented as an in situ method for real-time monitoring. In order to calibrate the sensor, electrolyte SoH was determined using the capacity measured in the cycling battery operation reaching deep charge/discharge states achieved in a constant voltage technique. The derived correlation between RI and OCV provides a powerful technique for SoH monitoring without knowing the full history of the battery operation providing the least mean error of 1.83% at OCV of 1.4 V. As a result, the proposed method is an important step for development of advanced control-monitoring tools that could assure reliable and efficient long-cycling operation of VRFB systems.

cheng W., sun X., Ye S., Yuan B., Sun Y., Marsh J., Hou L.

Integrated microring resonator structures based on silicon-on-insulator (SOI) platforms are promising candidates for high-performance on-chip sensing. In this work, a novel sidewall grating slot microring resonator (SG-SMRR) with a compact size (5 µm center radius) based on the SOI platform is proposed and demonstrated experimentally. The experiment results show that the refractive index (RI) sensitivity and the limit of detection value are 620 nm/RIU and 1.4 × 10–4 RIU, respectively. The concentration sensitivity and minimum concentration detection limit are 1120 pm/% and 0.05%, respectively. Moreover, the sidewall grating structure makes this sensor free of free spectral range (FSR) limitation. The detection range is significantly enlarged to 84.5 nm in lab measurement, four times that of the FSR of conventional SMRRs. The measured Q-factor is 3.1 × 103, and the straight slot waveguide transmission loss is 24.2 dB/cm under sensing conditions. These results combined with the small form factor associated with a silicon photonics sensor open up applications where high sensitivity and large measurement range are essential.

Li H., Wu L., Jin Y., Wu A.

Tapia-Brito E., Riffat J., Wang Y., Wang Y., Ghaemmaghami A.M., Coleman C.M., Erdinç M.T., Riffat S.

Severe acute respiratory syndrome coronavirus (SARS-CoV)-2, the virus that causes the coronavirus disease (COVID)-19, is primarily transmitted through respiratory droplets which linger in enclosed spaces, often exacerbated by HVAC systems. Although research to improve HVAC handling of SARS-CoV-2 is progressing, currently installed HVAC systems cause problems because they recirculate air and use ineffective filters against virus. This paper details the process of developing a novel method of eliminating air pollutants and suspended pathogens in enclosed spaces using Photocatalytic Oxidation (PCO) technology. It has been previously employed to remove organic contaminants and compounds from air streams using the irradiation of titanium dioxide (TiO2) surfaces with ultraviolet (UV) lights causing the disintegration of organic compounds by reactions with oxygen (O) and hydroxyl radicals (OH). The outcome was two functional prototypes that demonstrate the operation of PCO-based air purification principle. These prototypes comprise a novel TiO2 coated fibre mop system, which provide very large surface area for UV irradiation. Four commercially accessible materials were used for the construction of the mop: Tampico, Brass, Coco, and Natural synthetic. Two types of UV lights were used: 365 nm (UVA) and 270 nm (UVC). A series of tests were conducted that proved the prototype's functionality and its efficiency in lowering volatile organic compounds (VOCs) and formaldehyde (HCHO). The results shown that a MopFan with rotary mop constructed with Coco fibres and utilising UVC light achieves the best VOC and HCHO purification performance. Within two hours, this combination lowered HCHO by 50% and VOCs by 23% approximately.

Zhao C., Yuan S., Cheng X., Zheng Z., Liu J., Yin J., Shen S., Yan X., Zhang J.

Catalyst utilization is an important determinant of proton exchange membrane fuel cell performance, and increasing the catalyst utilization is one of the most critical approaches to reducing the catalyst loading in PEMFC. 4-phase stochastic reconstruction method based on the variable-resolution Quartet Structure Generation Set (QSGS) algorithm is utilized to elucidate the influence of different parameters of electrode preparation, including the porosity, the dispersion degree of carbon agglomerate, ionomer content, and carbon support size, on the catalyst utilization in the catalyst layer. It was found that there exist optimal values for the porosity, dispersion degree of carbon agglomerate, ionomer content, and carbon support sizes in CLs and any deviations from these optimal values would lead to transport issues of electron, proton and mass within CLs. Taking electron, proton and mass transport into consideration simultaneously, the optimal Pt utilization is 46.55% among 48 cases in this investigation, taken at the carbon support diameter of 40 nm, the porosity of 0.4, the agglomerate spatial density of 25 μm−3 and I/C at 0.7. The selection of porosity, ultrasonic dispersion technique and ionomer content for conventional electrode preparation requires compromises on mass, electron and proton transport, leading to catalyst utilization in CLs hardly exceeding 50%. Therefore, the next generation of catalyst layer design and preparation technology is desired.

Butt M.A.

Integrated optics is a field of study and technology that focuses on the design, fabrication, and application of optical devices and systems using integrated circuit technology. It involves the integration of various optical components, such as waveguides, couplers, modulators, detectors, and lasers, into a single substrate. One of the key advantages of integrated optics is its compatibility with electronic integrated circuits. This compatibility enables seamless integration of optical and electronic functionalities onto the same chip, allowing efficient data transfer between optical and electronic domains. This synergy is crucial for applications such as optical interconnects in high-speed communication systems, optical sensing interfaces, and optoelectronic integrated circuits. This entry presents a brief study on some of the widely used and commercially available optical platforms and fabrication methods that can be used to create photonic integrated circuits.