Maximum Open Circuit Voltage Research Articles

Synthesis of pyrene-based Fe(II)-complex and its photovoltaic properties

<p>(E)-2-((pyren-1-ylmethylene)amino)phenol (3) containing pyrene linked through an imine bond to a phenol unit was synthesized and its Fe-complex 4 was prepared. The complex 4 is characterized by infrared (IR), x-ray diffraction (XRD) and UV-Vis spectroscopy techniques. The synthesized complex was used as a sensitizer in a solar cell structure. From the current density (J) - voltage (V) curve obtained, the values of the short-circuit current density (JSC), maximum current density (JM), open-circuit voltage (VOC) and maximum voltage (VM) for the complex 4 were determined as 6.68 mA /cm2, 4.73 mA /cm2, 0.56 V and 0.41 V, respectively. Using these parameters, the fill factor (FF) and power conversion efficiency value (η) of complex 4 were calculated as 0.52 and 1.94, respectively. This value shows that complex 4 can be used as an effective sensitiser in solar cell applications.</p>

Simultaneous Production of Bioethanol and Bioelectricity in a Membrane-Less Single-Chambered Yeast Fuel Cell by Saccharomyces cerevisiae and Pichia fermentans

Production of bioethanol and bioelectricity is a promising approach through microbial electrochemical technology. Sugars are metabolized by yeast to produces ethanol, CO2, and energy. Surplus electrons produced during the fermentation can be transferred through the circuit to generate electricity in a microbial fuel cell (MFC). In the present study, a membrane-less single-chambered microbial fuel cell was developed for simultaneous production of bioethanol and bioelectricity. Pichia fermentans along with well-known ethanol-producing yeast Saccharomyces cerevisiae were allowed to ferment glucose. S. cerevisiae demonstrated maximum open circuit voltage (OCV) 0.287 ± 0.009 V and power density 4.473 mW m−2 on the 15th day, with a maximum ethanol yield of 5.6% (v/v) on the 12th day. P. fermentans demonstrated a maximum OCV of 0.318 ± 0.0039 V and power density of 8.299 mW m−2 on 15th day with an ethanol yield of 4.7% (v/v) on 12th day. Coulombic efficiency (CE) increased gradually from 0.002–0.471% to 0.012–0.089% in the case of S. cerevisiae and P. fermentans, respectively, during 15 days of the experiment. The result indicated that single-chambered fuel cell can be explored for their potential applications for ethanol production along with clean energy generation.

Static concentrating photovoltaic modelling using MATLAB

The world has recorded an increasing interest and staggering investment in renewable technology in the last two decades, specifically in solar photovoltaic (PV). Concentrating PV (CPV) is one of PV’s technology advancements and is gaining popularity for integration in a building. Various CPV designs are currently being investigated by researchers. The aim of this paper is to design and develop a MATLAB programme that can predict the electrical properties of a static concentrator that is designed with a ±40° acceptance angle. The programme was utlizied to determine the angular characteristics of the static concentrator between acceptance angle of -50° and 50°. It is proposed that the optoelectronic gain, Copto-e values be incorporated into the model to simulate a CPV design. The incident angle values (within ±50°) were chosen to demonstrate that the static concentrator could collect solar energy within its designed acceptance angle of ±40°. The current-voltage and power-voltage characteristics are generated for each simulation, and critical parameters such as the maximum power, open-circuit voltage, short-circuit current, and optoelectronic gain were identified and measured. The programme was found to be able to determine the electrical properties for the static concentrator.

Enhanced catalytic performance of Cu2ZnSnS4/MoS2 nanocomposites based counter electrode for Pt-free dye-sensitized solar cells

Low abundance, high cost and corrosiveness towards the liquid electrolyte is the main limitation of Platinum (Pt) as a counter electrode (CE) in dye-sensitized solar cells (DSSCs) in spite of its excellent electrochemical properties. The present study focuses to enhance the electrochemical properties of CZTS by compositing it with MoS2 towards the replacement of Pt. Pure CZTS, pure MoS2, CZTS/MoS2 nanocomposites are synthesized by hydrothermal method, then characterized and compared to analyze their properties. The outcomes of characterizations techniques from XRD, Raman, XPS, SEM, EDS and TEM confirmed the formation of CZTS/MoS2 nanocomposites. The electrochemical characterizations and Impedance analysis of the pure CZTS, pure MoS2 and CZTS/MoS2 are compared. Results showed enhanced catalytic property and lower charge transfer resistance for the CZTS/MoS2 nanocomposites. Nanocomposite with 8 wt% of MoS2 in CZTS exhibited higher carrier concentration of 6.126 × 1018 cm−3, higher mobility of 5.03 cm2Vs−1 and lower resistivity of 2.62 Ωcm compared to CZTS and other nanocomposites. Electrical conductivity and catalytic activity were improved with increase in the wt% of MoS2 in the Cu2ZnSnS4/MoS2 nanocomposites. DSSC device fabricated by interpolating di-tetrabutylammonium cis-bis(isothiocyanate)bis(2,2″-bipyridyl-4,4′dicarboxylato) ruthenium (II) (N719) dye-loaded titanium dioxide (commercial P25 TiO2 as photoanode) and with CZMo8 (as CE) using iodine/iodide as a liquid electrolyte exhibited the maximum open circuit voltage of 720 mV, a short circuit current of 8.45 mA/cm2, a fill factor of 0.66, and a power conversion efficiency of 4.07%.

Omni-directional wind-driven triboelectric nanogenerator with cross-shaped dielectric film

Triboelectric nanogenerators (TENGs) are actively being researched and developed to become a new external power unit for various electronics and applications. Wind is proposed as a mechanical energy source to flutter the dielectric film in wind-driven TENGs as it is clean, abundant, ubiquitous, and sustainable. Herein, we propose a TENG structure with dielectric films bent in four directions to collect the wind energy supply from all directions, unlike the conventional wind-driven TENGs which can only harvest the wind energy from one direction. Aluminum (Al) layer was intercalated within the dielectric film to improve electrostatic induction, resulting in improved triboelectric performances. Maximum open-circuit voltage (Voc) of 233 V, short-circuit current (Isc) of 348 µA, and output power density of 46.1 W m− 2 at an external load of 1 MΩ under a wind speed of 9 m s− 1 were revealed, and it faithfully lit “LED” characters composed of 25 LEDs.

Predicting Early EVA Degradation in Photovoltaic Modules From Short Circuit Current Measurements

One of the common failures in photovoltaic modules is the degradation of the ethylene-vinyl acetate (EVA) encapsulant due to prolonged ultraviolet exposure and other environmental stress factors, such as temperature and humidity. Experimental studies have shown that significant reduction in the optical transmission due to EVA degradation leads to loss in the available power by more than 50%. In this article, a novel approach to predict the early degradation of EVA encapsulant is proposed by correlating EVA degradation with short-circuit current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SC</sub> ). An electrical circuit simulator, simulation program with integrated circuit emphasis (SPICE), is used to evaluate the short-circuit current obtained under varying optical transmission caused by EVA discoloration. The simulation follows three steps: simulation of the transmitted solar spectrum; simulation of the spectral short-circuit current density; and simulation of the current-voltage (I-V) curve to obtain short-circuit current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SC</sub> ), maximum power output (P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> ), open-circuit voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OC</sub> ) and fill factor. Results show that the reduction in short-circuit current due to EVA degradation differs from the reductions expected due to a spectrally-uniform reduction of intensity of the solar irradiance. Both types of variation are linear, however, the slope due to EVA degradation is larger than the slope obtained for normal intensity variations in the solar irradiance. This model, when applied in conjunction with solar irradiance measurements, can predict early onset of EVA encapsulant failure, thereby enabling preventative measures to be taken.

Magnetic lifting triboelectric nanogenerators (ml-TENG) for energy harvesting and active sensing

Triboelectric nanogenerators (TENG) have been reported with the advantages of high adaptability and easy integration in recent years, which, however, have been facing with the challenge of effective stimuli in different applications. In this study, we develop magnetic lifting triboelectric nanogenerators (ml-TENG) for energy harvesting and active sensing under cyclic loading, such as traffic. The ml-TENG take advantage of magnetic force to provide repulsive force to trigger for relative displacement between the electrode and dielectric layers in the sliding mode. Experimental and numerical studies are conducted to investigate the electrical performance of the ml-TENG under cyclic loading. The open-circuit voltage of 4 V and output power of 340 µW per capsule are obtained. In the end, we develop a self-powered velocity active sensing system using the ml-TENG, and the field test is conducted to obtain the maximum open-circuit voltage of 7.2 V at the velocity of 15 km/h. The reported ml-TENG provide a powerful tool to develop active sensing systems for real-world applications, such as velocity detection.

Proton exchange membrane based on poly (vinyl alcohol) as support and alpha alumina as filler and its performance in direct methanol fuel cell

A series of proton exchange membranes (PEMs) are fabricated by using an inexpensive organic poly (vinyl alcohol) as the base and inorganic alpha alumina as the filler/ionomer of the membrane. The physical, mechanical and thermal characterization of the synthesized membranes is carried out by using tools such as Fourier transform-infrared (FT-IR), X-ray diffraction (XRD), field emmision scanning electron microscopy (FE-SEM), nano-indentation, and thermogravimetric analysis (TGA). The tensile strength of the membranes was measured on a universal testing machine (UTM), and the results demonstrate that the that the membranes possess high mechanical stability (tensile strength of up to 80.4 MPa). The TGA results indicate the high thermal performance (stable up to 260 °C) of the membranes. Other important performance parameters like the water uptake, the methanol uptake, and swelling ratio are determined. In addition, the chemical stability of the membranes is also evaluated. The ion exchange capacity (max 0.59 meq/g), the transport number (max 0.72) and the proton conductivity (max 2.9 mS/cm) are measured and reported. A single-cell DMFC performance testing is carried out at different temperatures. The maximum open-circuit voltage of 0.74 V, current density of 28.4 mA/cm2 and power density of 6.3 mW/cm2 are obtained at 60 °C.

Power Generation from an Elastic Leidenfrost Hydrogel Piston Enabled Heat Engine

Leidenfrost phenomenon has been observed since 1756. Diverse Leidenfrost phenomenon based heat engines were developed for converting the thermal energy into mechanical form. Limited to the weak force, the Leidenfrost heat engines are rarely reported with usable electric power output. Here we propose an elastic Leidenfrost heat engine based power generator for the demonstration of thermal-to-electric power conversion. A saturated sodium polyacrylate super absorbing polymer sphere is employed as hydrogel piston for harvesting thermal energy to trigger elastic deformation and mechanical bouncing. A lightweight contact separation mode triboelectric nanogenerator (TENG) plays a role for the conversion from the tiny mechanical input into usable electric power. The dynamics of the hydrogel piston on hot plates, force generation during bouncing and electric power output are measured experimentally. The effects of piston stroke, working temperature, and water absorption rate of the hydrogel piston are discussed. A maximum open-circuit voltage of 22 V and peak power of 280 μW was obtained by a single 2-gram hydrogel piston and the output electric power from the hydrogel piston based power generator successfully lights up 22 commercial LEDs.

Assessment of different organic substrates for Bio-Electricity and Bio-Hydrogen generation in an Integrated Bio-Electrochemical System

The population explosion and exponential increase in energy demand of the world have created enormous stress on finite fossil fuels and posed a threat to the environment. The sustainable Bio-Electrochemical Systems which include Microbial Fuel Cells (MFC), Microbial Electrolysis Cells (MEC) etc. can generate energy from waste. The present study has intended to utilize Sewage sludge (SS), Compost leachate (CL), and Mess Food waste (FW) as an organic substrate in an Integrated Bio-Electrochemical system to evaluate the bioelectricity generation potential in dual-chambered H type MFCs, then utilization of digestate from MFCs for Bio-hydrogen production in MECs. The maximum open-circuit voltages of 595 mV, 505 mV, and 690 mV were recorded in SS, CL, and FW fed MFC respectively, and their corresponding peak power densities of 1.8 ± 0.1 W/m2, 1.3 ± 0.1 W/m2 and 2.4 ± 0.1 W/m2 respectively were generated. The COD removal of 62.37%, 66.8%, and 50.19% were achieved for MFC fed with SS, CL, and FW respectively. The digestate fed MECs had further shown COD removal of 55.26%, 64.40% and 46.61% of the digestate in the "MFC turned MEC" system. The corresponding volumes of gas produced per gram of COD removal were reported as 23.8, 18.1 and 55.1 for SS, CL and FW respectively. The overall COD removal by bio-electrochemical system (BES) of 83.25%, 88.23 % and 73.41% for SS, CL and FW were achieved. The higher OCV of 690 mV and 55.1 mL of bio-hydrogen per gram of the COD removed has suggested the suitability of the FW for Integrated Biochemical system. . The comparative higher performance of FW as feeds has established itself as a potent choice for bio-electricity and bio-hydrogen production.

Improved performance of a zinc–air fuel cell by coupling zinc particle fuel and flowing electrolyte

ABSTRACT This research examined the operation of zinc–air fuel cell (ZAFC) with two different anode fuel types, namely zinc plate and zinc particle. The cell operation with zinc particle fuel also included potassium hydroxide (KOH) as the flowing electrolyte, and the optimal electrolyte flow rate was established as 150 mL/min. The performance of the two cells was compared in terms of power performance and reduction in reactor internal resistance. The power performance evaluation depends on three main factors including open-circuit voltage (OCV), power, and current density. The ZAFC with particle fuel was better than the plate-type fuel cell with maximum OCV of 1.41 V and current and power density values of 684 mA/cm2 and 553.6 mW/cm2, respectively. The particle fuel cell with flowing electrolyte also showed better reduction in external ohmic resistance, kinetic resistance, and mass-transport resistance with values of 0.41, 0.14, and 0.19 Ω, respectively, but a slight increase in internal resistance of the particle ZAFC (0.20 Ω) over plate anode fuel cell (0.18 Ω) was observed. Nyquist and Bode plots were used to explain the results in this study.

Ba-doped ZnO nanorods: Efficient piezoelectric filler material for PDMS based flexible nanogenerator

We report the synthesis of pure and Ba-doped ZnO nanoparticles by chemical co-precipitation technique with the aim to study the viability of Ba-doped ZnO nanoparticles as piezoelectric fillers in composite piezoelectric nanogenerators. The influence of Ba-doping on the structural, ferroelectric and piezoelectric properties of ZnO has been investigated in detail. Structural study by powder XRD reveals the formation of single hexagonal wurtzite phase for both pure and Ba-doped ZnO nanoparticles. Hexagonal rod-like morphology has been observed for both the samples from field emission scanning electron microscopy. The ferroelectric properties of Ba–ZnO have also been investigated and the remnant polarization and coercive field was measured to be 0.049 μC/cm2 and 4.088 kV/cm. In addition, Ba–ZnO sample shows a typical butterfly curve and the average d33 value of 41.28 p.m./V. Owing to improved piezoelectric properties and reduced leakage current, Ba–ZnO nanorods were utilized for the fabrication of flexible PDMS polymer based nanogenerators. A series of nanogenerators were fabricated with different amounts of Ba–ZnO filler varied from 10 to 40 wt% to individuate the optimal nanofiller concentration. The device with 30 wt% of Ba–ZnO generated the maximum open-circuit output voltage of about 10.5 V upon perpendicular compression of 2 kgf. Thus, Ba–ZnO:PDMS based composite device can be explored for application in mechanical energy harvesting and driving portable electronics.

Numerical modeling of multi-junction solar cell-based CIGS with two sub-cells in parallel using silvaco TCAD

The multi-Junction solar cell technique was suggested for achieving high efficiency. This paper describes the simulation of a solar cell for double junction CGS/CIGS solar cell using Silvaco ATLAS software. The simulated device performance was demonstrated in the form of current-voltage (I-V) characteristics and quantum efficiency (QE). By simulation of the tow solar cell, we have obtained for solar the top cell maximum opencircuit voltage 1.15V, a short circuit current density of 18.74 mA, a fill factor (FF) of 87.79 % and an efficiency of 18.27% and for the bottom solar cell is maximum opencircuit voltage 0.57 V, a short circuit current density of 21.52 mA, a fill factor (FF) of 82.82% and an efficiency of 10.26%. For the Tandem whose sub-cells are tied in parallel, the maximum open-circuit voltage 1.16V, a short circuit current density of 29 mA, a fill factor (FF) of 83.06% and an efficiency of 28.11%.

Experimental Investigation of Thermoelectric Power Generator Using D-Mannitol Phase Change Material for Transient Heat Recovery

Thermoelectric technology, a solid state technology that converts heat energy into usable electricity, have gained a great attention in the field of renewable energy resources. This paper presents an importance of phase change material (PCM) of D-Mannitol attached in the hot side of commercially available Bi2Te3 based thermoelectric module on the recovery of transient heat so as to boost the conversion efficiency. The open circuit voltage and short circuit current of TEG attached in the D-Mannitol were recorded for heating and cooling in the temperature range of 323 K–450 K. During heating cycle, the thermal energy produced by external heater is stored in the PCM which is used as a heat source for power generation during cooling. Particularly, the maximum open circuit voltage drawn in presence of external heater is 1.23 V which moderately reduces to 0.4 V after 15 min. The maximum power drawn in the heater on and heater off are 20.8 mW and 0.48 mW respectively.

Direct-Electron-Transfer-Based Microfluidic Glucose Biofuel Cell With CO2 Laser Ablated Bioelectrodes and Microchannel.

Miniaturized microfluidic electrochemical energy devices can produce power without the need for a separator reducing a considerable amount of fabrication complications. Enzymatic biofuel cells, with glucose as a fuel, are capable of producing energy from biological fluids in the presence of biocatalysts. The tedious fabrication procedures can be avoided by making electrodes and microchannel using laser ablation technique on polyimide substrates. In this work, a microfluidic enzymatic biofuel cell (MEBFC) has been presented with CO2 laser-ablated microchannel and bioelectrodes using a mediatorless approach. Multiwalled carbon nanotubes (MWCNT) have been used as a promoter to enhance the electron transfer rate. The fabricated MEBFC shows good power performance supplying [Formula: see text]/cm2 with a maximum open-circuit voltage of 260 mV.

P-type heterojunction bifacial solar cell with rear side carrier selective contact

Molybdenum oxide (MoOx), owing to its large work function, is an attractive material for hole-selective contact (HSC) in crystalline Si-based solar cells because it introduces upward band bending when constructed into a heterojunction silicon (SHJ) cell structure. In this study, we fabricated a p-type SHJ bifacial solar cell with a rear-side MoOx HSC layer. The MoOx thickness was varied from 3 to 15 nm, and cell bifaciality was addressed. The cell efficiency decreased when the MoOx thickness was increased to more than 5 nm. A maximum front-side cell efficiency of 17.89% was obtained, while the rear efficiency was 16.02%, which shows the potential of MoOx for p-type bifacial cell fabrication. The maximum open circuit voltage (VOC) and short circuit current density (JSC) for the front side were 635.71 mV and 35.57 mA/cm2, respectively, while the rear side VOC and JSC were 623.62 mV and 32.67 mA/cm2, respectively. The interfacial properties were carefully studied as a function of MoOx thickness. This work demonstrates the importance of selecting MoOx for p-type crystalline silicon (c-Si) solar cells.

A stretchable triboelectric nanogenerator made of silver-coated glass microspheres for human motion energy harvesting and self-powered sensing applications.

Wearable triboelectric nanogenerators (TENGs) have recently attracted great interest because they can convert human biomechanical energy into sustainable electricity. However, there is a need for improvement regarding the output performance and the complex fabrication of TENG devices. Here, a triboelectric nanogenerator in single-electrode mode is fabricated by a simple strategy, which involves a sandwich structure of silicone rubber and silver-coated glass microspheres (S-TENG). The S-TENG exhibits a remarkable performance in harvesting human motion energy and as flexible tactile sensor. By optimizing the device parameters and operating conditions, the maximum open-circuit voltage and short-circuit current of the S-TENG can reach up to 370 V and 9.5 μA, respectively. The S-TENG with good stretchability (300%) can be produced in different shapes and placed on various parts of the body to harvest mechanical energy for charging capacitors and powering LED lights or scientific calculators. In addition, the good robustness of the S-TENG satisfies the needs of reliability for flexible tactile sensors in realizing human–machine interfaces. This work expands the potential application of S-TENGs from wearable electronics and smart sensing systems to real-time robotics control and virtual reality/augmented reality interactions.

Lactuca sativa leaf extract concentration optimization using evolutionary strategy as photosensitizer for TiO2-filmed Grӓtzel cell

To enhance the power efficiency of a dye-sensitized solar cell (DSSC) or Grӓtzel cell, photosensitizer concentration must be fine-adjusted within the ultraviolet and near-infrared spectrum. In this study, evolutionary computing through genetic algorithm (GA) and evolutionary strategy (ES) was employed to determine the optimal combination of chlorophyll a and anthocyanin concentrated dyes extracted from cultivated Lactuca sativa var. Altima (green) and Rania (violet). ES configured with 0.6 selection rate, 0.08 Gaussian mutation rate, and 0.4 crossover rate generated the optimal dye concentration of 16.5% green and 83.5% violet yielding 24.093% efficiency in AM 1.5 sunlight intensity. It also exhibited the maximum short-circuit current (4.591 mA), open-circuit voltage (688.7 mV), filling factor (0.762), and power (3.162 mW). UV-Vis spectrophotometry confirmed that combining chlorophyll (663 nm) and anthocyanin (520 nm) pigments increases photon energy utilization. It is supported by the 2.39 eV optical energy bandgap and 2.009 Km−1 absorption coefficient of the ES-based cell. FTIR verified that no new bond or reaction was formed by combining pigments rather they coexist with each other allowing a broader light spectrum to excite the ground state electrons in the TiO2 layer. Thus, ES-combined dyes increased the efficiency by a factor of 9.965 and 2.299 from green and violet pigments respectively.

Research on a Piezoelectric Energy Harvester with Rotating Magnetic Excitation

This paper presents a piezoelectric energy harvester with rotational magnetic excitation. Through the rotation of the rotating body, the intermittent magnetic force between the driving magnet and the tip magnetic mass drives the piezoelectric element to vibrate nonlinearly to generate electrical energy. The working principle and vibration model of the proposed energy harvester are studied theoretically and experimentally. With two driving magnets, 5-g tip magnetic mass, and 8-mm radial excitation distances, the piezoelectric energy harvester captures energy efficiently. The results demonstrate that the piezoelectric energy harvester produces three resonance frequencies of 5 Hz, 8 Hz, and 10 Hz. When the rotation frequency is 8 Hz, the maximum open-circuit voltages of the primary and auxiliary piezoelectric beam is 63.24 V and 30.38 V, respectively. The primary and auxiliary piezoelectric beam gets the maximum average power with external resistance is 125 KΩ and 75 KΩ, respectively. The maximum average power of the primary and auxiliary piezoelectric beam is 12.24 mW and 3.92 mW, respectively. At the maximum power of the primary and auxiliary piezoelectric beam, the voltage across the resistance is 39.12 V and 17.12 V, respectively.

Sliding triboelectric nanogenerator with staggered electrodes

The sliding mode triboelectric nanogenerator (S-TENG) is a sustainable power source that converts electrical energy from linear or rotary mechanical motion. This paper proposes an S-TENG with staggered electrodes (S-TENG-SE), which can considerably enhance the output performance of S-TENG by simply changing the spatial arrangement of the electrodes. A staggered arrangement of electrodes simultaneously increases both the open-circuit voltage and the transfer charge. The superiority of S-TENG-SE compared to S-TENGs with a conventional electrode arrangement is confirmed by a series of simulations and experiments. As a result, the maximum open-circuit voltage, transfer charge, and short-circuit current were all increased by 3.3, 2.7, and 4.5 times, respectively, compared to the conventional S-TENG. The S-TENG-SE has a favorable structure for improving the performance of S-TENG, and this work will provide valuable insight into the advancement of S-TENG technology.