Materials for Renewable and Sustainable Energy最新文献

In this work, we report that hydrogen (H₂) doped in n-type a-Si:H thin films strongly influences the electronic correlation in increasing the conversion output power of solar cells. Type n a-Si:H thin films were grown using PECVD on ITO substrates with various H2-doping, to obtain various thin films for solar-cell applications. N-type a-Si:H thin films were prepared, and then characterized using ellipsometric spectroscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy. The addition of doped-H₂ to the thin layer shows a decrease in optical conductivity, while the energy gap in the thin layer shows a significant increase in the a-Si:H-type thin layer. Our results show that H₂ doping plays a very important role in the electronic structure, which is indicated by the significant energy gap difference. On the other hand, the bond structure of each H2-doped thin film showed a change from amorphous to nanocrystalline structures which were evenly distributed in each H₂-doped bonding. Overall, we believe that the addition of doped-H₂ to our findings could help increase the power conversion output of the solar cell due to the modification of the electronic structure.

Bioenergy is one of several renewable energy options derived from biomass that can help satisfy our energy needs.  Anaerobic digestion is a viable method for producing bioenergy in the form of biogas from biomass. The anaerobic digestion process is challenged with low biogas recovery, and low-quality effluent or CO₂ emission, which contribute to environmental pollution and the carbon footprint in the atmosphere. Computational process modelling and simulation can provide realistic information for dealing with the technological challenges involved with anaerobic digestion. In this study, modeling and simulation of the simplified anaerobic digestion process were done using SuperPro Designer software fed with biomass feedstock containing carbohydrates, proteins, and fats, as well as yeast, at 37 °C mesophilic temperature. The anaerobic digestion process yielded 89.655% of CH₄ and 10.345% of CO₂ and confirmed that the carbohydrate feedstock produces more CH₄ composition in the biogas. Mineralization of CO₂ using MgO yielded 0.23% MgCO₃, consuming > 99% of the CO₂ produced during the anaerobic digestion process. Environmental impact assessment of the effluent discharge yielded 0.142 kg Slds/L volatile solid with 6.01% COD reduction per batch of the anaerobic digestion process in an anaerobic digester with 90% (1.925 kg/batch) feedstock dosage. The data indicate that single-batch effluent cannot be discharged into the environment, hence indicating the possible recycling for multiple anaerobic digestion processing. The results are a significant guide for the realistic scalable production of high-quality biogas for bioenergy application, CO₂ mineralization, and environmental remediation.

Nowadays, addressing the drawbacks of liquid electrolyte-based batteries is a hot and challenging issue, which is supposed to be fulfilled through solid electrolyte systems such as polymer electrolytes. Polymer blend electrolytes (PBEs) are widely investigated as viable options to solve the undesired characteristics of their liquid counterparts and also the poor ionic conductivity of homopolymer-based electrolytes. Even though PBEs outperform homopolymer-based electrolytes in terms of performance, the conductivity of pristine PBEs is quite low for practical applications (i.e. below 10^–3 S/cm at room temperature). A very promising approach to solve this limitation is to incorporate additives into the electrolyte systems, to select suitable polymeric materials and to employ the desired synthesizing techniques as the performance of PBEs is strongly dependent on the selection of polymeric materials (i.e. on the inherent properties of polymers), the nature and amount of salts and other additives, and also the techniques employed to synthesize the polymer blend hosts and/or polymer blend electrolytes, determining the functionality, amorphousness, dielectric constant, dimensional stability, and, ultimately, the electrochemical performances of the system. This paper reviews the different factors affecting the miscibility of polymer blends, PBEs synthesizing techniques, the thermal, chemical, mechanical and electrochemical characteristics of PBEs, and also the challenges and opportunities of PBEs. Moreover, the paper presents the current progress of polymer blend electrolytes as well as future prospects for advancing polymer blend electrolytes in the energy storage sectors.

In this study, new polypyrrole films (ppy) were synthesized using a physical plasma deposition (PAPVD) system; where the equipment design and methodology for plasma-assisted pyrrole polymerization were improvement. The morphology, functional groups, and thermal stability of the polymer network films were characterized by X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) techniques, respectively. The electrochemical properties of the films as capacitor were evaluated by cyclic voltammetry and electrochemical impedance spectroscopy. The results observed by SEM showed that the ppy 100W-1 and ppy 100W-2 films present uniformity in their structure. The analyses of TGA and DSC confirmed the improvement in stability; meanwhile for 100W-1 film, the presence of ppy bonds was corroborated by XPS. Plasma-activated ppy 100W-1 film exhibited higher capacitance and minor Rct resistance than that obtained for ppy 100W-2 film. The specific capacitances values of ppy 100W-1 and ppy 100w-2 films are 196 and 150 F/g in 1 M KCl. After charging and discharging tests of 1000 cycles at 5 mA cm⁻² current density of ppy 100W-1 film retains 89% of its initial capacitance. Therefore, ppy 100W-1 film showed to be a promising material for use as an electrochemical capacitor.

Doping TiO₂ with noble metals, transition metals, cations, anions have yielded very promising results in enhancing photocatalytic activity of TiO₂ in the visible region and its role in generating alternate forms of energy. Noble metals in general can effectively slow down carrier recombination. However, the study of Pd and Ni as dopant can lead to a reliable and versatile TiO₂-modified photocatalyst. In this paper, we explore the optical properties of Pd- and Ni-doped TiO₂ by doping with 4.17% Ni and Pd dopant concentrations. The optical properties prove that Ni-doped TiO₂ can absorb well in the visible region with an absorption coefficient of 1 × 10⁵ cm⁻¹. Hence, Ni-doped TiO₂ can successfully alter the electronic and optical properties of TiO₂ for favorable future applications. In the visible region, absorption coefficient of Pd-doped TiO₂ supercell is around 1.2 × 10⁵ cm⁻¹ which is comparatively greater than that of pure TiO₂ confirming its utility as a versatile and viable visible light photocatalyst. The other optical properties like reflectivity, refractivity, extinction coefficient and electron energy loss spectrum have also been studied.

In this study, different Cobalt–Copper mixed oxides compositions for supercapacitor electrodes have been prepared, by means of electrodeposition and thermal annealing. The chemical–physical and electrochemical characterization of electrodes, as well as the effect of different Co/Cu in the ratios on the crystal lattice, electrode morphologies, and electrochemical performance of the electrodes, were investigated using X-ray diffraction (XRD), scanning electron microscopic (SEM) and cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge (GCD) tests. The results indicated that the electrode prepared from 0.06 M CoSO₄·7H₂O + 0.04 M CuSO₄·5H₂O solution (CC4) had a better electrochemical performance. The initial capacity of the CC4 electrode was 28.3 mAh/g at a scan rate of 5 mV/s with a coulombic efficiency of 94%. CC4 electrode featured capacity retention of 79.2% at a constant current density of 1 A/g after 5000 cycles.

The primary goal of the current study is to improve the specific capacitance of electric double-layer (EDLC) device using biomass (Tribulus Terrestris) derived activated carbon electrodes synthesized by chemical activation method. Furthermore, high surface area carbon electrodes are characterized using X-ray diffraction (XRD), RAMAN spectroscopy, and scanning electron microscopy (SEM) to confirm the morphological structure. Finally, the electrochemical performance of fabricated EDLC proves a good agreement data using Cyclic Voltammetry (CV), Low Impedance Spectroscopy (LIS), and Galvanostatic Charge–Discharge (GCD) analysis showing the high specific capacitance of 115 Fg⁻¹ for the optimized 1:2 activated carbon material.

This research work aims to study photovoltaic systems that generate energy for self-consumption using different traditional technologies, such as silicon, and emerging technologies, like nanowires and quantum. The photovoltaic system without batteries was implemented in a residential property in three different places, in Portugal. According to Portuguese Law, the sale of surplus energy to the grid is possible but the respective value for its selling is not defined. To evaluate the project viability, two different analyses are considered: with and without the sale of surplus energy to the grid. Results show that if there is no sale of excess energy produced to the grid, the project is not economically viable considering the four different technologies. Otherwise, using traditional technologies, the project is economically viable, presenting a payback time lower than 10 years. This shows that the introduction of nanostructures in solar cells is not yet a good solution in the application of solar systems namely with the current law. Furthermore, independently of the used technology, the current Portuguese law seems to difficult the investment return, which should not be the way to encourage the use of renewable sources.

Zinc oxide is one of the most researched semiconductors owing to the outstanding properties that make it useful in various industrial applications, such as solar cells and other optoelectronics. In this work, ZnO thin films were prepared in five different concentrations and doped with four nitrogen atoms from triethylene tetramine (TETA) to fabricate a ZnO for optoelectronic applications using an electrodeposition technique. The doped ZnO thin films were synthesized and deposited on ITO glass substrates. The deposited thin films were annealed at 400°Cfor 60min in a furnace under the same conditions. The thin films' optical, electrical, and surface morphological properties were characterized using UV–Vis Spectrophotometer, Four Point Probe (FPP), and Scanning Electron Microscope (SEM), respectively. The optical properties confirmed the film's suitability for various transparent device applications with a high optical transmittance of about 90% at the wavelength between 250 and 950 nm. The optical band gaps of 3.25 eV to 3.50 eV were obtained at ZnO concentrations from 0.2 M to 1.0 M. The SEM images depicted a polycrystalline nature of the films with irregular nanoparticle shapes across the substrates. Electrical results established the high conductivity of nitrogen-doped ZnO thin films, thereby making the thin films suitable as transparent conducting oxides for devices such as solar cells and optoelectronics.

Tin oxide (SnO₂) nano-crystalline thin films were deposited on silicon and glass substrates at room temperature by sputtering at a constant power of 30 W and different working pressure of 10, 7, and 5 mTorr. Surface morphology, electrical and optical properties of the films were investigated to optimise the deposition condition of the films as electron transport layer (ETL) for high-power conversion efficiency perovskite solar cells. The films were characterized by scanning electron microscopy (SEM), UV–Vis–NIR Spectrophotometer, and Four-point probe. SnO₂ films obtained at working pressure of 10 mTorr exhibited uniform surface morphology with high light transmittance (90%) and conductivity (4 S/m). These sputtered SnO₂ films appeared to have shown promising properties as ETL for PSC, and further investigation is justified to establish the optimal fabrication parameters and resulting energy conversion efficiency.