Efficiency Of Photovoltaic Solar Cells Research Articles

Modeling Finned Thermal Collector Construction Nanofluid-based Al2O3 to Enhance Photovoltaic Performance

Extensive research has been conducted to address the issue of the reduced efficiency of solar photovoltaic (PV) cells at high temperatures. To address this problem, a hybrid cooling system has been developed. This system uses a thermal collector to convert waste heat into reusable heat. Selecting the best configuration and operational parameters for the collector is crucial for maximizing system performance. To achieve this, we conducted computational fluid dynamics (CFD) modeling using ANSYS. Various factors affecting the cooling of PV solar cells were analyzed, including the collector design, mass flow rate, and concentration of the Al2O3 nanofluids. Results showed that the 12S finned thermal collector system exhibits the lowest temperature for PV solar cells, at approximately 29.654 oC. The electrical efficiency of PV solar cells is influenced by the concentration of Al2O3 nanofluids. We found that the 12S finned collector system with 1% water/Al2O3 nanofluid achieved the highest efficiency (approximately 11.749%) at a flow rate of 0.09 kg/s. The addition of finned collectors affects efficiency and variations in fluid mass flow rates, and there is no relation between the connector type and different Al2O3nanofluid concentrations. In other words, the cooling system can be optimized to enhance the efficiency of the PV solar cells under high-temperature conditions. Doi: 10.28991/CEJ-2023-09-12-03 Full Text: PDF

Strategies Toward End-group Engineering of Chrysene Core-based Non-fullerene Acceptors for High Performance Organic Solar Cells: A DFT Study

In this study, seven new molecules (OA1–OA7) were introduced with the goal of enhancing the photovoltaic efficiency of solar cells. All these molecules were evaluated by using density functional theory (DFT). All the designed molecules have shorter band gap and higher values of [Formula: see text] than the reference. For confirming the charge mobility, the optoelectronic characterization has been carried out by densities of states (DOS), transition density matrix (TDM), molecular electrostatic potential (MEP) and reorganization energy. The [Formula: see text] values in designed molecules were also improved. The stability of designed molecules was also confirmed by the analysis of non-covalent interactions (NCIs). These results elaborate on the superiority of these novel-designed molecules over pre-existing (R) molecule as potential blocks for better organic solar cell applications.

Performance enhancement of photovoltaic solar collector using fins and bi-fluid: Thermal efficiency study

This work exhibits a three-dimensional numerical investigation of a solar collector Photovoltaic Thermal (PV/T) bi-fluid based on the use of dual exchangers cooling with both water and air simultaneously. The effect of the absorber plate design and water mass flow rate (mf) of water and natural airflow has been studied according to the fins added to the system, which mainly includes a flat plate of aluminum attached to the tubes of aluminum. The objective is to analyze the effects of water mf fluctuating between 0.01 and 0.02 kg/s, fins location and number (from 20 to 40 fins), and changing solar irradiation values (100 to 1050 W/m2) on the flow structure and thermal efficiency of photovoltaic solar cells. The hybrid collectors studied are made of monocrystalline photovoltaic cells and an absorber plate of aluminum in the lower of the PV module. An evaluation was made between three configurations of bi-fluid (air and water) PV/T manifolds according to the number of fins. The first configuration is a hybrid PV/T system containing tubes without fins. The second configuration is a hybrid PV/T system containing tubes attached with 20 fins. The third configuration is a hybrid PV/T system containing tubes attached with 40 fins. The results confirm that the thermal efficiency of the PV/T system using (water and air) as a working fluid increase with increasing the number of fins (from 20 to 40 fins) and with increasing solar radiation (100 to 1050 W/m2), but it decreases a little with increasing mf of water (0.01 to 0.02 kg/s) by about 1.1%. For the mf of water equal to 0.01 kg/s, the thermal efficiency of the PVT system configurations 1, 2, and 3 are equal to 50.54%, 52.33%, and 54.25%, respectively. The optimal design for good cooling of the photovoltaic cells and higher yields of the hybrid collector is the third configuration with a water mf of 0.01 kg/s.

Investigation of the Effect of Vacuum and Air Annealing on the Structural, Optical and Electrical Properties of Radio Frequency Sputtered WO<sub>3</sub> Thin Films

Thin films of tungsten oxide were deposited on glass substrates by the radio frequency (RF) reactive sputtering from a high purity tungsten metal target (99.9%) with a diameter of 10 cm. The reactive sputtering was carried out in an argon-oxygen gas mixture containing 20% of O2 and 80% of Ar. The used RF power is 200 W while fixing the deposition time at 120 min. Finally, the prepared films were annealed at different temperatures (350 °C, 400 °C, 450 °C, 500°C and 550 °C) for 1 hour under air and under vacuum. X-ray diffractograms showed that the deposited thin films crystallized in Hexagonal/Monoclinic WO3 phase. It was found that the crystallite size varies with the annealing temperature and the lattice parameters is a= 7.3064Å, b = 7.5292Å, c = 7.6875Å and a=b= 7.3242Å, c= 7.6624 Å, for h-WO3 and m-WO3 structures, respectively. Scanning Electron Microscopy (SEM), Raman spectra confirmed the formation of WO3 thin films. In addition, optical transmittance data revealed that the optical bandgap of the films decreases with increasing the annealing temperature. Electrical measurements revealed that annealing in air results in more resistive samples, which should be taken into account in future investigations, especially as buffer layers for efficient photovoltaic solar cells. Keywords: Vacuum, Tungsten oxide, Raman spectroscopy, RF Sputtering method, RF Power, Annealing temperature.

Experimental investigations of the microscale concentrated photovoltaic/thermal system based on a solar parabolic trough concentrator

The world’s electricity generation from photovoltaic systems has been growing significantly for the last two decades. Nowadays, one of the most interesting trends in the conversion of solar radiation is the use of concentrating solar power collectors. Among other well-known technologies, quite a new solution is concentrated photovoltaic thermal installations, which use photovoltaic panels as a power converter. This paper presents the experimental works carried out on the prototypical micro-scale parabolic-through solar concentrator equipped with monocrystalline silicon solar cells located on the hexagonal receiver tube. The main goal of these investigations was to determine the possibility of enhancing the efficiency of photovoltaic solar cells by placing them under concentrated solar radiation. Obtained results showed, that the maximum power of tested solar cells increased approx. 29% from 14.40 ±0.50We to 18.60 ±0.60We using concentrated sunlight in comparison to efficiency measured in direct sunlight. It was demonstrated that the use of solar radiation concentrators is justified in the case of solar installations, even with low concentration ratio factors.

The use of a hybrid photovoltaic/thermal (PV/T) collector system as a sustainable energy-harvest instrument in urban technology

A solar cell is a converter that uses semiconductor material to convert photon energy packets. The electrons located in the material's crystalline structure can escape from the bonds between their atoms and generate electricity. Photovoltaic (PV) solar cells can work via diffuse radiation and have the highest efficiency among other types of solar cell generation. Photovoltaic Thermal Collector (PVT)-based active cooling technology makes it possible to increase the efficiency of PV solar cells and to generate thermal energy at the same time through the direct conversion of solar radiation. Therefore, this study modeled various riser configurations on PVT collectors to cool PV solar cells using water heat transfer fluids and nanofluids: TiO2, SiO2, and Al2O3. The mass flow rates were varied. An ANSYS models a simulation of the heat transfer phenomenon between the PV cell layer and the fluid. Only the heat transfer phenomenon generated from the natural convection of the PV cell layer is studied using steady-state thermal ANSYS with simulated controlled conditions. The radiation intensity of 1000 W/m2 has the photovoltaic solar cells with the most negligible efficiency. The semicircular collector configuration with water at a mass flow rate of 0.5 kg/s demonstrated the highest electrical efficiency, achieving 11.98%.

Halide Diffusion Equilibrium and Its Impact on Efficiency Evolution of Perovskite Solar Cells

AbstractUnderstanding the degradation mechanism of perovskite solar cells (PSCs) is of particular importance to solve their instability issue, which is one of the major hindrances toward commercialization. Here, it is shown that a halide diffusion equilibrium exists at the heterointerface of perovskite devices, which strongly impacts the evolution of device performance. The combined experimental and theoretical studies reveal that halide components diffuse from perovskite to fullerene layers in a p‐i‐n PSC device and equilibrate with an iodine density of 1018–1019 cm−3 within 80 h under dark aging condition. It is found that there is a strong correction between the device efficiency and halide diffusion equilibrium of PSCs, as the diffused halides can chemically dope the transport layer and result in the nonstoichiometric perovskite surface, leading to both initial enhancement and long‐term loss of the photovoltaic efficiency of solar cells. In response to this issue, a predoping strategy is developed to attain the halide diffusion equilibrium once the device is fabricated, thereby avoiding the further halide migration and initial efficiency variations. As a result, the as‐prepared PSC achieved an efficiency of 23.13% as well as stable power output under continuous one sun illumination.

Investigation the performance of PV solar cells in extremely hot environments

Manufacturers typically define photovoltaic (PV) modules under conventional test settings of 1000 W/m2 at 25 °C, which may not be possible anywhere in the globe, because high ambient temperature is one of the most critical factors affecting photovoltaic solar cell efficiency. In this study, we will investigate the ambient temperature as well as the open circuit voltage, output power, short circuit current, and efficiency in hot regions such as Mecca (Makkah). It also discusses the correlations between PV efficiency, solar radiation, and ambient temperature. On the other hand, the addition of a layer of copper sulphate at a concentration of 1% is investigated. The use of a copper sulphate layer enhanced the PV characteristic in cases where the PV cell temperature was reduced by around (0.3–34.6 °C), while also increasing the open circuit voltage, output power, efficiency, and fill factor.

Investigation of Thermal Collector Nanofluids to Increase the Efficiency of Photovoltaic Solar Cells

Active cooling technology of photovoltaic thermal (PVT) system allows lowering the working temperature to increase the efficiency of photovoltaic (PV) solar cells. In addition, the absorbed heat produces thermal energy simultaneously through the working fluid in the collector. Therefore, in this study, the modeling of the riser configuration of the PVT collector for cooling PV solar cells was carried out using a working fluid and varied mass flow rates. It is used to find the effect of working fluid and mass flow rate on the resulting efficiency. ANSYS 18.2 system analysis software is used to simulate phenomena that occur. The natural convection phenomena of the PV cell layer were explored using ANSYS Steady State-Thermal. The simulation of the heat transfer phenomenon between the PV cell layer and the liquid was done using ANSYS Fluent. The improvement in energy generation efficiency achieved by utilizing a thermal collector system to cool PV solar cells reaches 49.8%. The maximum PV solar cell electrical efficiency value comes when the rectangular collector riser arrangement is modeled with SiO2 nanofluid working fluid and a mass flow rate of 0.01 kg/s. Each variation used was not significantly different from the efficiency of the PV solar cells produced.

Photoacoustic and photothermal and the photovoltaic efficiency of solar cells: A tutorial

Optical losses are the major drawback to overcome in the solar energy industry and development. Conversion of solar radiation into heat accounts for over 80% of the incident solar energy, which is driven by several aspects like the chosen design and encapsulation of the devices, built-in materials, and the mismatch between the solar spectrum and the active cell's bandgap energy. Photoacoustic (PA) and photothermal (PT) methods are characterization techniques based on the heat generation after the illumination of a material and respective detection. Since the beginning of the solar panel industrial development, these methods have been successfully applied to evaluate the photovoltaic efficiency of devices and the thermophysical parameters of related materials. Here, we present the state-of-art of application of these PA and PT methods to characterize solar cell devices and their built-in materials. Historical aspects, conceptual mechanisms of the basic phenomena, and perspectives on their application for energy-conversion measurements in the new frontier of solar cell research will be discussed.

Engineering 2D semiconductors of PbI2@NdI2 and NdI2@CuI with respect of photovoltaic and solar cell applications

In this study, given the high capability and potential of PbI2, CuI halide semiconductors and NdI2 in new technologies, PbI2@NdI2 and NdI2@CuI nanostructures were introduced and their electro-optical properties were investigated by density functional theory calculations. The results showed that the morphology of PbI2@NdI2 and NdI2@CuI appropriate for stable synthesize and strength structures. Both compounds have the majority carrier densities of hole and the charge carriers density of PbI2@NdI2 was higher than that of NdI2@CuI. Investigation calculation on optical properties showed that the optical behavior of the two structures is favorable at UV and IR wavelengths. However, light absorption of NdI2@CuI in the visible region is higher than PbI2@NdI2 and in the UV region is less than PbI2@NdI2. Also, the optical gap of PbI2@NdI2 and NdI2@CuI was calculated at 2 eV and 1.3 eV, respectively. The static dielectric constant of PbI2@NdI2 and NdI2@CuI were obtained at 1.05 and 0.95, respectively. Therefore, calculation studies show that PbI2@NdI2 and NdI2@CuI nanostructures can improve the efficiency of photovoltaic solar cells by increasing the absorption of the solar spectrum. Also, PbI2@NdI2 has lower structural losses at different wavelengths and can be a good combination for making high power laser filters.

Improvement in photovoltaic efficiency of solar cells with ZnO nanorods and electrophoretically-adsorbed dyes

ZnO nanorods grown on the F-doped tin oxide glass by a chemical bath deposition were sensitized by the electrophoretic technique or the conventional soaking method, and the resulting electrodes were applied to photoanodes of dye-sensitized solar cells (DSSCs). The DSSC with an electrophoretically-sensitized ZnO layer showed an increase in both the short-circuit current (Jsc ) and the open-circuit voltage (Voc ), resulting in a 220% enhancement of photovoltaic performance, when compared to that of the reference cell with a conventionally-sensitized ZnO layer. By applying the electrophoresis to dye adsorption, dye-loading amount was considerably increased, and thereby enhancing the light harvesting efficiency and reducing the interfacial charge recombination between photoinjected electrons and I3 −. This led to the enhancement in Jsc and Voc , compared to those of the reference cell.

Improving the Efficiency of Stand-Alone Solar PV Power Plants

As a source of alternative energy, solar energy has apparent advantages, including a renewable, inexhaustible, and environmentally friendly resource. However, it has not become widely spread in the Russian Federation. Among the disadvantages of using solar energy are high equipment cost, low efficiency of photovoltaic solar cells, the generated electrical energy instability. The spatio-temporal variability of solar access causes electrical energy instability. It is possible to increase solar photovoltaic plant efficiency by using a tracking system to change the plant sun's spatial orientation. The paper offers mathematical and simulation models of a solar photovoltaic plant with a solar tracking system that allows the plant to be automatically oriented to the sun by matching the production mode and the solar access level. The use of the azimuth plant control system on the sun will increase the power production of the solar PV plant by an average of 28%. The same value will increase by 40% when using the full plant control system.

Designing a new heat sink containing nanofluid flow to cool a photovoltaic solar cell equipped with reflector

BackgroundToday, one of the concerns is to reduce the efficiency of photovoltaic solar cells as their temperature rises. Therefore, cooling photovoltaic is one of the challenges that will be addressed in this article. In this paper, the cooling of a photovoltaic cell by a newly designed heatsink is numerically investigated. MethodTwo nanofluids were used to cool the heatsink. The heatsink consists of an Aluminum cover and two main parts in which there are numerous channels with zigzag walls. Moreover, the two-phase mixture method was employed to simulate the nanofluids flow based on finite volume method. The performance of the heatsink and photovoltaic were studied for concentration of the nanoparticles at different Reynolds numbers. FindingsUsing nanofluids increases the heat transfer coefficient but also increases the required pumping power. By adding 2% alumina at the Reynolds number of 150, the heat transfer coefficient increases by 83%. Furthermore, Al2O3/H2O nanofluids has better thermal resistance and temperature uniformity than CuO/H2O nanofluids for heatsink and photovoltaic. The addition of alumina nanoparticles increases the thermal efficiency of photovoltaic while the addition of copper oxide nanoparticles reduces it. Moreover, by increasing the Reynolds number from 50 to 150, the thermal efficiency increased by 7%.

Influence of Cu content on the physical characteristics of CuxGaCr0.1S2 thin films for intermediate band solar cells

Intermediate band semiconductors can increase the efficiency of photovoltaic solar cells via sequential absorption of photons in a wider range of the solar spectrum. The introduction of Cr substituting Ga atoms in the chalcopyrite CuGaS2 is proposed to create a suitable intermediate band, investigating the influence of the Cu/Ga ratio on the structural, morphological, optical, and electrical characteristics. For this purpose, CuxGaS2 and CuxGaCr0.1S2 thin films (with x ranging from 0.8 to 1.2) are prepared by modulated evaporation from elemental sources and analyzed comparatively by X-ray diffraction, Raman spectroscopy, atomic force microscopy, spectrophotometry, and Hall effect measurements. The incorporation of Cr produces an in-gap absorption that is independent of the Cu/Ga ratio. The mean crystallite size, surface roughness, and electrical conductivity increase with the Cu content in both CuxGaS2 and CuxGaCr0.1S2.

Antiferromagnetism-induced second-order nonlinear optical responses of centrosymmetric bilayer CrI3

Antiferromagnetism (AF) in AB′-stacked centrosymmetric bilayer (BL) CrI3 breaks both spatial inversion (P) and time-reversal (T) symmetries but maintains the combined PTsymmetry, thus inducing novel second-order nonlinear optical (NLO) responses such as second-harmonic generation (SHG), linear electric-optic effect (LEO) and bulk photovoltaic effect (BPVE). In this work, we calculate AF-induced NLO responses of the BL CrI3 based on the density functional theory with the generalized gradient approximation (GGA) plus onsite Coulomb correlation (U), i.e., the GGA+U method. Interestingly, we find that the magnetic SHG, LEO and photocurrent in the AF BL CrI3 are huge, being comparable or even larger than that of the well-known nonmagnetic noncentrosymmetric semiconductors. For example, the calculated SHG coefficients are in the same order of magnitude as that of MoS2 monolayer (ML), the most promising 2D material for NLO devices. The calculated LEO coefficients are almost three times larger than that of MoS2 ML. The calculated NLO photocurrent in the CrI3BL is among the largest values predicted so far for the BPVE materials. On the other hand, unlike nonmagnetic semiconductors, the NLO responses in the AF BL CrI3 are nonreciprocal and also switchable by rotating magnetization direction. Therefore, our interesting findings indicate that the AF BL CrI3 will not only provide a valuable platform for exploring new physics of low-dimensional magnetism but also have promising applications in magnetic NLO and LEO devices such as frequency conversion, electro-optical switches, and light signal modulators as well as high energy conversion efficiency photovoltaic solar cells.

Ferromagnetic, electric, and ferroelectric properties of samarium and cobalt co-doped bismuth ferrite nanoparticles

Pure and co-doped multiferroic bismuth ferrite (BFO) nanoparticles were synthesized by the sol-gel method. Samarium and cobalt were used as co-dopants in BFO. The co-doped composites had the formula Bi1-xSmxFe1-yCoyO3, where x = 0.1 and y = 0.05, 0.1, or 0.15. Rietveld refinement of X-ray diffraction patterns showed a well-arranged crystalline rhombohedral structure with space group R3c. The rhombohedral structure transformed to an orthorhombic structure with space group Pbam in co-doped BFO nanoparticles. The ferromagnetic properties of synthesized nanoparticles were investigated in detail. Bi0.9Sm0.1Fe0.85Co0.15O3 showed a large increase in saturation magnetization and remanent magnetization to 3.2 and 1.5 emu/g, respectively. The large increase in magnetization with a reasonable squareness ratio and coercive field of co-doped BFO nanoparticles means they have potential uses in memory and spintronic devices. Electric properties such as resistance, reactance, AC resistivity, and AC conductivity were analyzed as a function of frequency. The AC resistivity decreased and the AC conductivity increased greatly with increasing co-dopant concentration. The ferroelectric behavior of pure and co-doped samples was also investigated. The maximum polarization and remanent polarization greatly increased to 12.5 and 7.5 μC/cm2, respectively, in Bi0.9Sm0.1Fe0.85Co0.15O3. The increased conductivity and reduced resistivity of co-doped samples may also be useful in efficient photovoltaic solar cells.

Frequency conversion in lanthanide-doped sol-gel derived materials for energy applications

In order to increase the efficiency of photovoltaic solar cells, photon absorption in an extended range of the solar spectrum is necessary, for example by means of up-conversion (UC) of sub-bandgap photons to minimize transparency losses. While lanthanide (Ln)-doped luminescent layers may be deposited on cell materials to achieve spectral conversion by methods like CVD or PVD, sol-gel (SG) processing is a low-cost technology which may be a good alternative for this purpose. In this work, Ln-doped SG-derived active layers have been deposited by spin-coating onto c-Si substrates for frequency conversion, with particular emphasis on UC, involving host matrices like aluminosilicate glass and titania ceramic doped with the activator/sensitizer pair Er/Yb. White light emitting diodes (WLEDs) based on Ln-doped phosphors still have efficiency limitations, namely because the Stokes shift from UV/blue LED excitation to the emitted lower frequency visible light converts some of the pump energy into heat. However, if white light generation (WLG) is achieved through IR-pumped UC instead, the cost of the LED lamp will be reduced, while the energy loss from Stokes shift can be minimized. SG synthesis of Ln-doped oxide phosphors for UC in WLG has been achieved (Er/Yb and Tm/Er/Yb doping), based on aluminosilicate glass matrices. Photonic crystal-assisted UC emission has also been demonstrated in a Tm/Yb-doped Fabry–Perot microcavity (MC). The different materials have been characterized by XRD, SEM, ellipsometry and photoluminescence (PL) spectroscopies and their light emission has been analyzed with the help of CIE chromaticity diagrams.

Energy Management Strategy for Solar-Powered UAV Long-Endurance Target Tracking

In this study, two types of three-dimensional (3-D) flight-based energy management strategies for solar-powered unmanned aerial vehicle (SUAV) long-endurance target tracking are proposed. In SUAV dynamic modeling, we consider the influence of wind on SUAV kinematics. Aiming at the complexity of the long-endurance tracking, namely the long flight time and space spans, the influences of the wind, variations of temperature, air density and solar cell photovoltaic efficiency, and a finite battery capacity are considered in our modified SUAV energy model. Then, considering the mission flexibility, we design two types of energy management strategies that comprehensively utilize the solar energy, gravitational potential energy, and wind to address different situations. The proposed strategies can be divided into several stages in chronological order according to the solar irradiation conditions, electrical energy storage conditions, and relative motion relationships among the SUAV, target, and wind. We then design respective strategies for these stages. The core of our proposed energy management strategies is to design the corresponding objective functions in each stage and the switching conditions between adjacent stages. Finally, we verify our proposed strategies by comparison with the traditional 2-D tracking strategy in a 24-h target tracking mission, and the results show the validity of our proposed strategies.

Efficiency enhancement of photovoltaic performance of dye sensitized solar cell using conducting polymer electrolyte of different functional group

Dye-sensitized solar cells (DSSCs) which have a polymer electrolyte added to with various function groups were studied to determine the effect of their composition on the efficiency of the solar cell. Four function group polymers got employed, those groups are polymethylmethacrylate (PMMA), polyvinyl acetate (PVA), polyethylene oxide (PEO) and polyacrylonitrile (PAN). The iodine salt cation is caged by the function groups which cause a positive shift in the dye HOMO level and result in a deceleration in the recombination rate more than that of ordinary iodine electrolyte. The polymer electrolyte ionic conductivity improves the rate of the dye regeneration to make it faster than ordinary iodine as well. Adding pyridine to electrolyte solution makes the conduction band of the TiO2 more negative leading to an increase in the open circuit voltage (Voc). The photo generated current (Jsc) is increased by the employed configureuration, subsequently, the solar cell photovoltaic efficiency is enlarged. PVA is with highest efficiency at 8%, unlike the rest of the polymers which show lower efficiencies.