Charge Flow Research Articles

Multi-output AC/DC triboelectric generator with dual rectification

Triboelectric generators (TEGs) are state-of-the-art powering solutions for low-power Internet of Things (IoT) devices. TEGs convert periodic mechanical vibrations into cyclic charge flow between electrodes, establishing an alternating current (AC). AC output requires rectification prior to charging any load, creating additional circuitry and power requirements. In recent years, the focus has shifted towards developing direct current (DC) generators as potential direct powering solutions. In this work, a DC–TEG is realized using a novel topology involving mechanical switching between a pair of metal contacts. This switching is implemented in vertical contact-separation mode and therefore does not involve any significant friction between the electrodes and metal contacts, overcoming the major limitation of wear and tear in conventional mechanical switching DC–TEGs. The proposed device can obtain each half-cycle rectified output across distinct electrode pairs, which is crucial for conditioning the asymmetric output of the TEGs. An AC output can be simultaneously harvested between the pair of bottom electrodes. The complementary AC–DC outputs of this device can supply power to multiple loads at a time, or coupled together to produce an enhanced output. Placing two complementary TEG pairs adjacent to each other in this topology has the advantage of reducing the ambient electric field, which is critical in improving the charge retention capability of the TEG layers. The proposed device achieves peak instantaneous power of 1.05 μW for the DC output and 1.12 μW for the AC output across a 7 MΩ resistance. The applications of the device in driving commercial electronics, harvesting biomechanical energy, and as progressive alarming system are demonstrated. Due to its simple, flexible topology and AC-DC dual output, this device has the potential for powering multiple loads and applications in diverse scenarios.

Understanding chemical enhancements of surface-enhanced Raman scattering using a Raman bond model for extended systems.

In this work, we extend a previously developed Raman bond model to periodic slab systems for interpreting chemical enhancements of surface-enhanced Raman scattering (SERS). The Raman bond model interprets chemical enhancements as interatomic charge flow modulations termed Raman bonds. Here, we show that the Raman bond model offers a unified interpretation of chemical enhancements for localized and periodic systems. As a demonstration of the Raman bond model, we study model systems consisting of CO and pyridine molecules on Ag clusters and slabs. We find that for both localized and periodic systems, the dominant Raman bonds are distributed near the molecule-metal interface and, therefore, the chemical enhancements are determined by a common Raman bond pattern. The effects of surface coverage, thickness, and roughness on the chemical enhancements have been studied, which shows that decreasing surface coverage or creating surface roughness increases chemical enhancements. In both of these cases, the inter-fragment charge flow connectivity is improved due to more dynamic polarization at the interface. The chemical enhancement is shown to scale with the inter-fragment charge flow to the fourth power. Since the inter-fragment charge flow is determined by the charge transfer excitation energy, the Raman bond model is connected to the transition-based analysis of chemical enhancements. We also show that the SERS spectra of localized and periodic systems normalized by inter-fragment charge flows can be unified. In summary, the Raman bond model offers a unique framework for understanding SERS spectra in terms of Raman bond distributions and offers a connection between localized and periodic model systems of SERS studies.

Discharging Behavior of a Fixed-Bed Thermochemical Reactor under Different Charging Conditions: Modelling and Experimental Validation

Thermochemical heat storage has attracted significant attention in recent years due to potential advantages associated with very high-energy density at the material scale and its suitability for long-duration energy storage because of almost zero loss during storage. Despite the potential, thermochemical heat storage technologies are still in the early stage of development and little has been reported on thermochemical reactors. In this paper, our recent work on the charging and discharging behavior of a fixed-bed thermochemical reactor is reported. Silica gels were used as the sorbent for the experimental work. An effective model was established to numerically study the effect of different charging conditions on the discharging behavior of the reactor, which was found to have a maximum deviation of 10.08% in terms of the root mean square error compared with the experimental results. The experimentally validated modelling also showed that the discharging temperature lift increased by 5.84 times by changing the flow direction of the air in the discharging process when the charging level was at 20%. At a charging termination temperature of 51.25 °C, the maximum discharging temperature was increased by 2.35 °C by reducing the charging flow velocity from 0.64 m/s to 0.21 m/s. An increase in the charging temperature and a decrease in the air humidity increased the maximum discharging outlet temperature lift by 3.37 and 1.89 times, respectively.

Molecular Dynamics with Conformationally Dependent, Distributed Charges.

Accounting for geometry-induced changes in the electronic distribution in molecular simulation is important for capturing effects such as charge flow, charge anisotropy, and polarization. Multipolar force fields have demonstrated their ability to correctly represent chemically significant features such as anisotropy and sigma holes. It has also been shown that off-center point charges offer a compact alternative with similar accuracy. Here, it is demonstrated that allowing relocation of charges within a minimally distributed charge model (MDCM) with respect to their reference atoms is a viable route to capture changes in the molecular charge distribution depending on geometry, i.e., intramolecular polarization. The approach, referred to as "flexible MDCM" (fMDCM), is validated on a number of small molecules and provides accuracies in the electrostatic potential (ESP) of 0.5 kcal/mol on average compared with reference data from electronic structure calculations, whereas MDCM and point charges have root mean squared errors of a factor of 2 to 5 higher. In addition, MD simulations in the NVE ensemble using fMDCM for a box of flexible water molecules with periodic boundary conditions show a width of 0.1 kcal/mol for the fluctuation around the mean at 300 K on the 10 ns time scale. For water, the equilibrium valence angle in the gas phase is found to increase by 2° for simulations in the condensed phase which is consistent with experiment. The accuracy in capturing the geometry dependence of the ESP together with the long-time stability in energy conserving simulations makes fMDCM a promising tool to introduce advanced electrostatics into atomistic simulations.

Experimental Energetic and Exergetic Performance of a Combined Solar Cooking and Thermal Energy Storage System

Most solar cookers usually perform a single task of solely cooking food during sunshine hours. Solar cookers coupled with thermal energy storage (TES) material for off-sunshine cooking are usually expensive and require complex engineering designs, and cannot be used for dual purposes, for example, solar water heating and cooking. In this paper, a solar cooker that can perform dual tasks of cooking as well as storing thermal energy to be used during off-sunshine periods is presented. The experimental setup is composed of a parabolic dish, a solar receiver coupled with a flat plate and an oil-circulating copper coil for charging and discharging a storage tank. The objective of the experiment is to evaluate the energy and exergy thermal performance parameters of the dual-purpose system during charging and discharging cycles. The effect of the flow rate and the mass of the load are investigated while using sunflower oil as both the heat transfer fluid and the storage material. Charging and discharging experiments are conducted using four different flow rates (2, 3, 4, 5 mL/s), and with different masses (0.5, 1, 1.5, 2.0 kg) with water and sunflower oil as the test loads. The charging results show that the average energy and exergy rates as well as their corresponding efficiencies increase with an increase in the charging flow rate. On the other hand, the increase in the mass load tends to decrease marginally the average charging energy and exergy rates for water, and their corresponding efficiencies. For sunflower oil, the average charging energy and exergy rates and efficiencies showed a more pronounced decrease with an increase in the mass. Water generally shows higher charging and discharging energy and exergy efficiencies compared to sunflower oil with an increase in the flow rate. For discharging results, the correlations between the energy and exergy thermal performance parameters with respect to the flow rate and the heating load are not well defined possibly due to different initial storage tank temperatures at the onset of discharging and the inefficient discharging process which needs to be optimized in future.

Self‐powered 2D nanofluidic graphene pressure sensor with Serosa‐Mimetic structure

AbstractHigh‐performance self‐powered pressure sensors have attracted much attention due to their potential applications in bionic limbs, healthy motion detection, medical devices, and other fields. However, existing devices are either imperceptible to the pressure direction or require an external power source as a driving force. Here, a pressure sensor inspired by the structure of serosal membranes is reported, which contains a novel partially reduced graphene oxide (prGO) membrane. In this Serosa‐Mimetic structured membrane, a narrow “Trail” structure containing COOH is considered as an ion filter and ion conductor, which facilitates the directional migration of cations under external stimuli, resulting in a directional flow of net charges, resulting in current (or voltage) signal. Therefore, the prGO‐Trail membrane can be used as an ion transport layer to facilitate self‐powered pressure sensing. This pressure‐driven output voltage (and current), produced by ion selectivity, is linear with the applied pressure. The fabricated self‐powered bionic pressure sensor has good performance, the optimized response sensitivity is 0.282 nA Pa−1, the response/recovery time is 90/110 ms, and long‐term stability (1000 cycles), which provides a meaningful design idea and a larger open field of vision for the next generation of self‐driving bionic pressure sensors.image

Dielectric, magnetic and electrochemical characterization of CoFe2O4 nanoparticles and their application as an anode material in Li-ion battery

• Porosity of prepared nanoparticles decreases with annealing. • Cationic distribution from octahedral to tetrahedral site was found more. • Ferrimagnetic state was confirmed from the presence of two sextet patterns. • High value of discharge capacity for the electrode made up of CoFe 2 O 4 nanoparticles was observed. • 98 % of Columbic efficiency was observed during long cyclic processes. CoFe 2 O 4 nanoparticles with an average crystallite size of 35 nm were successfully synthesized by hydrothermal method. To illustrate the various physical and chemical properties of the nanoparticles various studies like TGA-DTA, XRD, SEM, TEM, FT-IR, Raman, Dielectric, Magnetic and Electrochemical properties were carried out. The sample annealed at 800 °C was employed to prepare the electrode for Li-ion battery. During cyclic processes of charging and discharging, the capacity of fading was observed after 1st cycle. On annealing the porosity of nanoparticles got reduced and the grain-to-grain contact area was increased. The good discharge capacity in the first reverse cycle revealed less porosity on the electrode, which facilitated the Li-ions to interact with the electrode to form Li 2 O. The electrochemical impedance analysis for fresh cell (before cycling) as well as after 50th cycles were performed. The flow of charge and diffusion of lithium ions to the working electrode were affected during cycling process and this was due to the formation of solid electrolyte interphase (SEI) on electrode.

Influence of operating conditions on the removal of silica and hardness by continuous electrocoagulation

In this study we investigated the removal of silica and hardness by continuous electrocoagulation (EC), based on treatment of oil-sands produced water. The effect of operating parameters including charge loading, flow rate, current density and polarity reversal period were investigated. As expected, the removal of silica and hardness increased with charge loading. At a fixed charged loading, the flowrate was found to have only a slight impact on silica removal. With both Fe and Al electrodes, a slight decrease in contaminant removal was observed at high flow rates, likely due to the shear breakup of flocs. For the range of conditions studied, the removal of Si, Ca and Mg increased with the polarity reversal time (from 30 s to 10 min), while the cell voltage (and energy consumption) decreased. The cell voltage obtained with 10 min polarity reversal was significantly lower than that for DC-EC. More than 80 % silica removal was achieved using a current density of 8 mA cm–2, charge loadings of 1500 C L⁻1 and 1000 C L⁻1 with Fe and Al electrodes respectively. Al-EC was found to consume less electrode material and energy while achieving higher Si, Ca, and Mg removal compared to Fe-EC. Economic evaluation revealed that for >80 % Si removal the specific energy consumption was 1.13 and 0.70 kWh m–3, with a total operating cost C$0.54 and C$0.50 per m3 of water treatment, for Fe and Al-EC respectively.

Thermal effects in spintronic materials and devices: An experimentalist’s guide

Research in spintronics often involves generation of heat in nanoscale magnetic systems. This heat generation can be intentional, as when studying effects created by an external applied temperature difference, or unintentional, coming as a consequence of driving relatively large charge currents through tiny structures. Understanding and controlling these thermal gradients can present challenges to experimentalists, which are related at some level to the fact that heat flow is much more difficult to isolate and manipulate than charge flow. This paper aims to provide a simple, intuitive framework to understand the fundamental issues that arise in spintronic materials and devices involving thermal gradients. The first goal is to provide simple tools to demonstrate how thermal gradients arise in systems with thin conducting films on bulk substrates. The main results are that a thermal gradient pointing perpendicular to the plane of a thin film supported on a macroscopic substrate is very common, even while the largest temperature drop in the system will exist across the bulk substrate itself. These results point to the need to understand the range of thermoelectric and magnetothermoelectric effects that can generate voltage signals and other responses to thermal gradients. I provide a brief review of these, along with relevant spin effects. The review concludes with examples and comments on several important ongoing issues in spintronics where thermal gradients play key roles.

Interference between Molecular and Photon Field-Mediated Electron Transfer Coupling Pathways in Cavities.

Cavity polaritonics creates novel opportunities to direct chemical reactions. Electron transfer (ET) reactions are among the simplest reactions, and they underpin energy conversion. New strategies to manipulate and direct electron flow at the nanoscale are of particular interest in biochemistry, energy science, bioinspired materials science, and chemistry. We show that optical cavities can modulate electron transfer pathway interferences and ET rates in donor-bridge-acceptor (DBA) systems. We derive the rate for DBA electron transfer when the molecules are coupled to cavity modes, emphasizing novel cavity-induced pathway interferences with the molecular electronic coupling pathways, as these interferences allow a new kind of ET rate tuning. The interference between the cavity-induced coupling pathways and the intrinsic molecular coupling pathway is dependent on the cavity properties. Thus, manipulating the interference between the cavity-induced DA coupling and the bridge-mediated coupling offers an approach to direct and manipulate charge flow at the nanoscale.

Toward the Industrial Application of Aluminum-Based Nanocomposite Material: A Study of Zn-Plating Process in Circuit Breaker Application.

This article explores the industrial application of an Al-based nanocomposite reinforced with 0.5 wt.% of multiwalled carbon nanotubes with a Zn mechanical plating applied to fulfill the field requirements of electrical devices. The performance of electric devices made from this nanocomposite material and with a Zn plating was compared with that of MCCB devices using a normal Cu compound. MCCB devices with the Al-based nanocomposites compound showed a better performance, with less heat generated due to a flow of electrical charge passing through the device. The presence of MWCNTs in the Al nanocomposite dissipates heat, maintaining a stable electrical resistance in the MCCB, in contrast to what happens with Cu compound, which increases its electrical resistance as the temperature in the device increases.

Impact of Solvent-Solute Hydrogen Bonding on Ultrafast Electron Transfer in a Trimetallic Iron-Ruthenium Complex

Transition metal complexes (TMCs) are widely used as light absorbers and catalysts for photochemical energy conversion processes such as photocatalytic reactions in liquid environments. Of particular interest are TMCs which incorporate multiple bridged metal centres because they represent a step towards more complex supramolecular assemblies that can ultimately enable control of the charge flow in solution-based photo-redox processes. However, the development of design guidelines for such molecular assemblies is impeded by an incomplete understanding of the coupling between their electronic and nuclear dynamics, including the interplay of TMCs with their liquid environment upon photoexcitation. Probing the involved processes requires high spatial sensitivity towards electronic motion and the ability to capture atomic motion on ultrafast timescales – a combination which is not readily available for optical transient spectroscopic techniques.X-ray free electron lasers (XFELs) have revolutionized the field of ultrafast science in recent years. XFELs generate tuneable and extremely bright X-ray pulses with a typical pulse duration of <30 fs, which are well-suited as an element-specific probe of ultrafast electronic and atomic motion in molecules and materials.1,2 Applied to TMCs, XFEL probes are sensitive to the local electronic structure in such molecular systems as well as to intra- and inter-molecular structural reorganization at an atomic level.3 In this talk, I will present work on the interaction of a linear trimetallic cyanide-bridged iron-ruthenium complex (FeRuFe) with its solvent environment, carried out using the LCLS XFEL facility at SLAC National Accelerator Laboratory. The focus of this study lies on elucidating how photoinduced intramolecular electron transfer processes in FeRuFe are affected by hydrogen bonding interactions between its cyanide ligands and the surrounding solvent molecules. In water, such solvent-solute hydrogen bonding interactions are stronger for Fe(II) than Fe(III), leading to substantial changes in solute-solvent interactions upon photoinduced electron transfer between metal centres.The experiment is performed in a pump-probe geometry on a liquid jet, where a visible/near-infrared pump induces a metal-to-metal charge transfer (MMCT) between Ru and Fe which is followed by an ultrafast back-electron transfer (BET). The excited state dynamics are monitored using hard X-ray pulses as a function of time delay between the laser pump and the X-ray probe pulses. To resolve and correlate electronic and structural dynamics upon MMCT excitation, we simultaneously perform ultrafast Fe Kβ X-ray emission spectroscopy (XES) and X-ray solution scattering (XSS) measurements, where XES is sensitive to the oxidation and spin state of the Fe centres and XSS provides information on atomic motion in solute and solvent, as demonstrated in previous work on a similar system.4 To evaluate the effect of solute-solvent hydrogen bonding interactions on the electron transfer dynamics, we perform measurements in a series of solvents with different hydrogen bonding properties, including water, methanol, and acetonitrile. We find that the BET increases as a function of decreasing hydrogen bonding ability of the solvent, and that distinct signatures of solvation dynamics are present in the scattering data. The resulting molecular level understanding of solvent reorganization coupled to electron transfer demonstrates that the strength and type of solute-solvent interactions are a central factor in determining the outcome of photoinduced charge transfer processes in TMCs.References Bergmann, U. et al. Using X-ray free-electron lasers for spectroscopy of molecular catalysts and metalloenzymes. Nat. Rev. Phys. 3, 264–282 (2021).Schoenlein, R. et al. Recent advances in ultrafast X-ray sources. Philos. Trans. R. Soc. Math. Phys. Eng. Sci. 377, 20180384 (2019).Gaffney, K. J. Capturing photochemical and photophysical transformations in iron complexes with ultrafast X-ray spectroscopy and scattering. Chem. Sci. 12, 8010–8025 (2021).Biasin, E. et al. Direct observation of coherent femtosecond solvent reorganization coupled to intramolecular electron transfer. Nat. Chem. 13, 343–349 (2021).

Enhanced Performance of Triboelectric Nanogenerators and Sensors via Cold Spray Particle Deposition.

In this study, a high-performance triboelectric nanogenerator (TENG) is developed based on cold spray (CS) deposition of composite material layers. Composite layers were fabricated by cold spraying of micron-scale tin (Sn) particles on aluminum (Al) and polytetrafluoroethylene (PTFE) films, which led to improved TENG performance owing to functionalized composite layers as friction layers and electrodes, respectively. As-sprayed tin composite layers not only enhanced the flow of charges by strong adhesion to the target layer but also formed a nano-microstructure on the surface of the layers, thereby increasing the surface area during friction. More importantly, the electricity generation performance was improved more than 6 times as compared to the TENG without CS deposition on it. From parametric studies, the TENG using the cold-sprayed composite layer produced an electrical potential of 1140 V for a simple structure with a 25.4 × 25.4 mm2 contact area. We also optimize the geometry and fabrication process of the TENG to increase the manufacturing efficiency while reducing the processing cost. The resultant sprayed layers and structures exhibited sustainable robustness by showing consistent electrical performance after the mechanical adhesion test. The proposed manufacturing approach is also applicable for processing three-dimensional (3D) complex layers owing to the technological convergence of a cold spray gun attached to a robotic arm, which makes possible to fabricate the 3D TENG. To elaborate, a composite layer having the shape of a 3D ball is produced, and the exercise status of the ball is monitored in real-time. The fabricated 3D ball using the TENG transmitted a distinguishable signal in real-time according to the state of the ball. The proposed TENG sensing system can be utilized as a self-powered sensor without the need of a battery, amplifier, and rectifier. The results of this study can potentially provide insights for the practical material design and fabrication of self-powered TENG systems.

The charging performance in contact electrification of fluorinated ethylene propylene surfaces by electrode bridge

Triboelectricity utilizes triboelectric nanogenerators (TENG) that transfer negative charges between two material surfaces that are in contact. Incomplete flow of charges results in charge accumulation on the material surfaces. In this study, we demonstrated that the accumulated charges could enhance induced output by contact electrification using electrode bridge (EB) to improve charge transfer mechanism. Triboelectric nanogenerator electrode bridge (TENG-EB) was fabricated using synergistic combination of polymer-polymer, polymer-metal, and metal-metal contacts during contact-electrification. Fluorinated ethylene propylene (FEP) film was fabricated using hot pressing technique. FEP crystallinity reached 85.8%, maximum temperature for ε r of FEP was 145 °C, and remanent polarization of FEP polymer was 4.2 µC mm – 2 . The individual events of the charge transfer during contact and separating of TENG-EB could be studied with a single electrode measurement. Separation of FEP, EB and electrode surfaces led to induced output of which signal was 4 times higher than TENG with non-EB. This mechanism utilized DC output that enhanced AC output signal for a given tapping frequency across a rectifier circuit. This new route is proposed for further research, development and invention in alternative energy field including energy harvesting and flexible electronic devices. • Charges event is demonstrated using electrode bridge (EB) induced output performance. • Triboelectric nanogenerator electrode bridge (TENG-EB) was fabricated based on synergistic combination of polymer-polymer, polymer-metal, and metal-metal contacts. • FEP-Al hot pressing is fabricated for electron blocking layer (EBL) has also played a vital role in blocking the electron overflow between a negative material and an electrode. • Output signal of TENG-EB is 4 times higher than that of a TENG non-EB.

Composite Porous Structure Formation by Platinum-Particle-Assisted Etching of a Highly-Doped p-Type Silicon: Evaluation of Charge Flow in Silicon

Electroless deposition of metal particles on silicon (Si) followed by the metal-assisted etching (metal-assisted chemical etching) is a simple way to fabricate Si nanostructures. A composite porous structure consisting of straight macropores and a mesoporous layer can be created by platinum (Pt)-particle-assisted etching. In this work, we studied the composite structure formation on a highly-doped p-Si (ca. 5 × 1018 cm−3) in comparison with a moderately-doped p-Si (ca. 1 × 1015 cm−3). The composite structure drastically changed: the ratio of mesoporous layer thickness to macropore depth increased to 1.1 from 0.16 by using the highly-doped Si instead of the moderately-doped Si. The open circuit potential of Si in the etching solution shifted to the positive direction by the Pt deposition. The potential shift of highly-doped Si was smaller than that of moderately-doped Si, which can be explained by the polarization characteristics. We calculated the band bending in Si by using a device simulator that reproduced the conditions of Pt-particle-assisted etching. The results indicated that, in the case of highly-doped Si, the consumption rate of positive holes at the Si surface away from the Pt particles increases due to the tunneling effect, which is consistent with the thick mesoporous layer formation.

Surface-Mounted Dipolar Molecular Rotors Driven by External Electric Field, As Revealed by Torque Analyses.

Driven by a high-speed rotating electric field (E-field), molecular motors with polar groups may perform a unidirectional, repetitive, and GHz frequency rotation and thus offer potential applications as nanostirrers. To drive the unidirectional rotation of molecular motors, it is crucial to consider factors of internal charge flow, thermal noise, molecular flexibility, and so forth before selecting an appropriate frequency of a rotating E-field. Herein, we studied two surface-mounted dipolar rotors of a “caltrop-like” molecule and a “sandwich” molecule by using quantum–mechanical computations in combination with torque analyses. We find that the rotational trend as indicated by the magnitude and the direction of torque vectors can sensitively change with the lag angle (α) between the dipolar arm and the E-field. The atomic charges timely flow within the molecule as the E-field rotates, so the lag angle α must be kept in particular intervals to maintain the rotor’s unidirectional rotation. The thermal effect can substantially slow down the rotation of the dipolar rotor in the E-field. The flexible dipolar arm shows a more rigid geometry in the E-field with higher rotation speed. Our work would be useful for designing E-driven molecular rotors and for guiding their practical applications in future.

Electron transfer via homogeneous phosphorus bridges enabling boosted photocatalytic generation of H2 and H2O2 from pure water with stoichiometric ratio

We report efficient and simultaneous production of H2 and H2O2 from photocatalytic pure water splitting over a novel heterojunction photocatalyst made of red phosphorus (RP) and CoxP co-modified P-doped g-C3N4 (PCN). The success relies on the formation of RP as an intermediate to link CoxP and PCN, introducing atomic-level homogeneous P-P/P-P bonds in the heterojunction. The crafted P-P/P-P bridges as unique channels enable controllable and smooth charge flow via strong electronic coupling between each component in the composite photocatalyst, endowing a boosted carrier kinetics. More significantly, RP also facilities a Z-scheme charge transfer that induces two-electron photocatalytic H2 and H2O2 production from pure water in 1:1 stoichiometry. The highest activity reaches 15.26 μmol h−1 for bifunctional chemical evolution under simulated solar light irradiation, with the apparent quantum efficiencies (AQE) of 6.2 % at 366 nm and 3.6 % at 425 nm, without using any noble metals on 50 mg of photocatalyst. The new insights of phosphorus bridges can be applied to other composite photocatalysts for reinforced reaction kinetics towards value-added chemicals generation.

Influence of layer thickness on the power conversion efficiency of tin halide-based planar heterojunction solar cells.

In recent years, perovskite-based solar cell technologies have sparked much interest. Organic-inorganic halide perovskites (OIHPs) are a type of perovskite that has shown promise in various optoelectronic applications. The power conversion efficiency (PCE) of organic-inorganic perovskite materials is improving with new materials development. However, inorganic materials studied in labs have limited PCE. Lead-free tin halide CH3NH3SnX3 shows good PCE. In this work, we study the electrical characteristics of tin halide as a perovskite absorbing layer in planar heterojunction solar cells with the help of GPVDM solar cell simulation software. A comparative study of power conversion efficiency has been done for tin halide of chloride, bromide, and iodide. The effect of electron and hole drift-diffusion, carrier continuity equations in position space to represent charge flow within the device, Poisson's equation, and charge carrier recombination has been studied in detail.

Low-energy amplitude-modulated radiofrequency electromagnetic fields as a systemic treatment for cancer: Review and proposed mechanisms of action.

Exposure to Low-Energy Amplitude-Modulated Radiofrequency Electromagnetic Fields (LEAMRFEMF) represents a new treatment option for patients with advanced hepatocellular carcinoma (AHCC). We focus on two medical devices that modulate the amplitude of a 27.12 MHz carrier wave to generate envelope waves in the low Hz to kHz range. Each provides systemic exposure to LEAMRFEMF via an intrabuccal antenna. This technology differs from so-called Tumour Treating Fields because it uses different frequency ranges, uses electromagnetic rather than electric fields, and delivers energy systemically rather than locally. The AutemDev also deploys patient-specific frequencies. LEAMRFEMF devices use 100-fold less power than mobile phones and have no thermal effects on tissue. Tumour type-specific or patient-specific treatment frequencies can be derived by measuring haemodynamic changes induced by exposure to LEAMRFEMF. These specific frequencies inhibited growth of human cancer cell lines in vitro and in mouse xenograft models. In uncontrolled prospective clinical trials in patients with AHCC, minorities of patients experienced complete or partial tumour responses. Pooled comparisons showed enhanced overall survival in treated patients compared to historical controls. Mild transient somnolence was the only notable treatment-related adverse event. We hypothesize that intracellular oscillations of charged macromolecules and ion flows couple resonantly with LEAMRFEMF. This resonant coupling appears to disrupt cell division and subcellular trafficking of mitochondria. We provide an estimate of the contribution of the electromagnetic effects to the overall energy balance of an exposed cell by calculating the power delivered to the cell, and the energy dissipated through the cell due to EMF induction of ionic flows along microtubules. We then compare this with total cellular metabolic energy production and conclude that energy delivered by LEAMRFEMF may provide a beneficial shift in cancer cell metabolism away from aberrant glycolysis. Further clinical research may confirm that LEAMRFEMF has therapeutic value in AHCC.

Solar light photocatalytic activity of CuO/TiO2 mixed oxide derived from conjugated azomethine metal complex for degradation of food colorants

This work illustrates the preparation of an effective photocatalyst, CuO/TiO2 nano metal mixed oxide (NMMO). The desired synthesis was carried out by calcination assisted reaction of Cu[DBAPD]/TiO2 at 650 °C. Additionally, the prepared nano metal mixed oxide material has also been confirmed by numerous characterization techniques such as XRD, FTIR, HRTEM, FESEM with EDS, XPS, BET, ESR and Photoluminescence which revealed the occurence of strong interfacial interactions between CuO and TiO2. The optical properties of the prepared NMMO have also been measured by UV–vis. spectroscopy. The prepared NMMO exhibited excellent photo-response for the total degradation of amaranth (99.21 %) as well as brilliant blue (99.68 %) after just 40 min during intense solar irradiation. It has been found that the photocatalytic degradation mechanism over the surface of CuO and TiO2 can be well explained by considering the charge flow from TiO2 to CuO. Such type of structure offered higher redox capability as well as improved separation of photogenerated charge carriers, thus providing phenomenal photocatalytic performance. In addition to this, the degradation process has been investigated utilizng mass spectrometry and UV–vis. spectral analysis. Moreover, the CuO/TiO2-NMMO photocatalytic material offered good stability and reusability and can therefore act as a strong contender to be use in environmental remediation.