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Records with Subject: Materials
Showing records 1 to 25 of 133. [First] Page: 1 2 3 4 5 Last
Aluminum⁻Titanium Alloy Back Contact Reducing Production Cost of Silicon Thin-Film Solar Cells
Hsin-Yu Wu, Chia-Hsun Hsu, Shui-Yang Lien, Yeu-Long Jiang
February 5, 2019 (v1)
Subject: Materials
Keywords: aluminum–titanium (AlTi) alloy, contact resistance, silicon thin-film solar cells
In this study, metal films are fabricated by using an in-line reactive direct current magnetron sputtering system. The aluminum⁻titanium (AlTi) back contacts are prepared by changing the pressure from 10 mTorr to 25 mTorr. The optical, electrical and structural properties of the metal back contacts are investigated. The solar cells with the AlTi had lower contact resistance than those with the silver (Ag) back contact, resulting in a higher fill factor. The AlTi contact can achieve a solar cell conversion efficiency as high as that obtained from the Ag contact. These findings encourage the potential adoption of AlTi films as an alternative back contact to silver for silicon thin-film solar cells.
Optimization of Electrochemically Deposited Highly Doped ZnO Bilayers on Ga-Rich Chalcopyrite Selenide for Cost-Effective Photovoltaic Device Technology
Dimitra N. Papadimitriou, Georgios Roupakas, Georgios G. Roumeliotis, Patrick Vogt, Tristan Köhler
February 5, 2019 (v1)
Subject: Materials
Keywords: annealing T-threshold, CIGS photovoltaics, current-voltage measurements, ECD process optimization, oriented Al:ZnO bilayers, scanning electron microscopy, transmittance/reflectance spectroscopy, van der Pauw measurement techniques, X-ray diffraction
High quality polycrystalline bilayers of aluminium doped ZnO (Al:ZnO) were successively electrodeposited in the form of columnar structures preferentially oriented along the ( 10 1 ¯ 1 ) crystallographic direction from aqueous solution of zinc nitrate (Zn(NO₃)₂) at negative electrochemical potential of EC = (−0.8)⁻(−1.2) V and moderate temperature of 80 °C on gallium rich (30% Ga) chalcopyrite selenide Cu(In,Ga)Se₂ (CIGS) with chemically deposited ZnSe buffer (ZnSe/Cu(In,Ga)Se₂/Mo/glass). The aluminium doped ZnO layer properties have initially been probed by deposition of Al:ZnO/i-ZnO bilayers directly on Mo/glass substrates. The band-gap energy of the Al:ZnO/i-ZnO reference layers was found to vary from 3.2 to 3.7 eV by varying the AlCl₃ solute dopant concentration from 1 to 20 mM. The electrical resistivity of indium-pellet contacted highly doped Al:ZnO sheet of In/Al:ZnO/i-ZnO/Mo/glass reference samples was of the order ρ ~10−5 Ω·cm; the respective carrier concentratio... [more]
Application of a LiFePO₄ Battery Energy Storage System to Primary Frequency Control: Simulations and Experimental Results
Fabio Massimo Gatta, Alberto Geri, Regina Lamedica, Stefano Lauria, Marco Maccioni, Francesco Palone, Massimo Rebolini, Alessandro Ruvio
January 31, 2019 (v1)
Subject: Materials
Keywords: battery energy storage system (BESS), LiFePO4 battery, primary frequency control
This paper presents an experimental application of LiFePO₄ battery energy storage systems (BESSs) to primary frequency control, currently being performed by Terna, the Italian transmission system operator (TSO). BESS performance in the primary frequency control role was evaluated by means of a simplified electrical-thermal circuit model, taking into account also the BESS auxiliary consumptions, coupled with a cycle-life model, in order to assess the expected life of the BESS. Numerical simulations have been carried out considering the system response to real frequency measurements taken in Italy, spanning a whole year; a parametric study taking into account different values of governor droop and of BESS charge/discharge rates (C-rates) was also performed. Simulations, fully validated by experimental results obtained thus far, evidenced a severe trade-off between expected lifetime and overall efficiency, which significantly restricts the choice of operating parameters for frequency cont... [more]
Perovskite Solar Cells: Progress and Advancements
Naveen Kumar Elumalai, Md Arafat Mahmud, Dian Wang, Ashraf Uddin
January 31, 2019 (v1)
Subject: Materials
Keywords: crystal structure, electronic structure, hysteresis, interface engineering, Perovskite photovoltaics, stability
Organic⁻inorganic hybrid perovskite solar cells (PSCs) have emerged as a new class of optoelectronic semiconductors that revolutionized the photovoltaic research in the recent years. The perovskite solar cells present numerous advantages include unique electronic structure, bandgap tunability, superior charge transport properties, facile processing, and low cost. Perovskite solar cells have demonstrated unprecedented progress in efficiency and its architecture evolved over the period of the last 5⁻6 years, achieving a high power conversion efficiency of about 22% in 2016, serving as a promising candidate with the potential to replace the existing commercial PV technologies. This review discusses the progress of perovskite solar cells focusing on aspects such as superior electronic properties and unique features of halide perovskite materials compared to that of conventional light absorbing semiconductors. The review also presents a brief overview of device architectures, fabrication me... [more]
Non-Vacuum Processed Polymer Composite Antireflection Coating Films for Silicon Solar Cells
Abdullah Uzum, Masashi Kuriyama, Hiroyuki Kanda, Yutaka Kimura, Kenji Tanimoto, Seigo Ito
January 30, 2019 (v1)
Subject: Materials
Keywords: antireflection coating, Czochralski silicon (CZ-Si), low-cost solar cell, nanoparticle, non-vacuum, spin coating, titanium oxide (TiO2), zirconium oxide (ZrO2)
A non-vacuum processing method for preparing polymer-based ZrO₂/TiO₂ multilayer structure antireflection coating (ARC) films for crystalline silicon solar cells by spin coating is introduced. Initially, ZrO₂, TiO₂ and surface deactivated-TiO₂ (SD-TiO₂) based films were examined separately and the effect of photocatalytic properties of TiO₂ film on the reflectivity on silicon surface was investigated. Degradation of the reflectance performance with increasing reflectivity of up to 2% in the ultraviolet region was confirmed. No significant change of the reflectance was observed when utilizing SD-TiO₂ and ZrO₂ films. Average reflectance (between 300 nm⁻1100 nm) of the silicon surface coated with optimized polymer-based ZrO₂ single or ZrO₂/SD-TiO₂ multilayer composite films was decreased down to 6.5% and 5.5%, respectively. Improvement of photocurrent density (Jsc) and conversion efficiency (η) of fabricated silicon solar cells owing to the ZrO₂/SD-TiO₂ multilayer ARC could be confirmed. T... [more]
Sustainable New Brick and Thermo-Acoustic Insulation Panel from Mineralization of Stranded Driftwood Residues
Anna Laura Pisello, Claudia Fabiani, Nastaran Makaremi, Veronica Lucia Castaldo, Gianluca Cavalaglio, Andrea Nicolini, Marco Barbanera, Franco Cotana
January 7, 2019 (v1)
Subject: Materials
Keywords: bio-based composite, Biomass, building envelope, energy efficiency in buildings, environmental sustainability, stranded driftwood residues, thermal and acoustical properties
There is considerable interest recently in by-products for application in green buildings. These materials are widely used as building envelope insulators or blocks. In this study, an experimental study was conducted to test stranded driftwood residues as raw material for possible thermo-acoustic insulation panel and environmentally sustainable brick. The thermal and acoustic characteristics of such a natural by-product were examined. Part of samples were mineralized by means of cement-based additive to reinforce the material and enhance its durability as well as fire resistance. Several mixtures with different sizes of ground wood chips and different quantities of cement were investigated. The thermo-acoustic in-lab characterization was aimed at investigating the thermal conductivity, thermal diffusivity, volumetric specific heat, and acoustic transmission loss. All samples were tested before and after mineralization. Results from this study indicate that it is possible to use strande... [more]
Environment-Friendly Heterogeneous Alkaline-Based Mixed Metal Oxide Catalysts for Biodiesel Production
Hwei Voon Lee, Joon Ching Juan, Taufiq-Yap Yun Hin, Hwai Chyuan Ong
January 7, 2019 (v1)
Subject: Materials
Keywords: biodiesel, mixed metal oxides, non-edible oil, solid catalyst, transesterification
The critical problem arising from the depletion of fossil fuels has stimulated recent interests in alternative sources for petroleum-based fuel. An alternative fuel should be technically feasible, readily available, sustainable, and techno-economically competitive. Biodiesel is considered as a potential replacement of conventional diesel fuel, which is prepared from non-edible and high-acid feedstock via transesterification technology. The focus of this study is to investigate the catalytic activity of mixed metal oxides (MMOs) as catalysts for biodiesel production by using non-edible jatropha oil as feedstock. Various types of MMOs (CaO-MgO, CaO-ZnO, CaO-La₂O₃, and MgO-ZnO) were synthesized via a co-precipitation method. In this study, transesterification activities are closely related to the physicochemical properties of catalysts. The presence of different active metals in the binary system greatly influenced the surface area, basicity, and the stability of catalysts. The catalytic... [more]
Recent Progress on the Key Materials and Components for Proton Exchange Membrane Fuel Cells in Vehicle Applications
Cheng Wang, Shubo Wang, Linfa Peng, Junliang Zhang, Zhigang Shao, Jun Huang, Chunwen Sun, Minggao Ouyang, Xiangming He
January 7, 2019 (v1)
Subject: Materials
Keywords: bipolar plate, catalyst, fuel cell automobile, gas diffusion layer, hydrogen energy, proton exchange membrane
Fuel cells are the most clean and efficient power source for vehicles. In particular, proton exchange membrane fuel cells (PEMFCs) are the most promising candidate for automobile applications due to their rapid start-up and low-temperature operation. Through extensive global research efforts in the latest decade, the performance of PEMFCs, including energy efficiency, volumetric and mass power density, and low temperature startup ability, have achieved significant breakthroughs. In 2014, fuel cell powered vehicles were introduced into the market by several prominent vehicle companies. However, the low durability and high cost of PEMFC systems are still the main obstacles for large-scale industrialization of this technology. The key materials and components used in PEMFCs greatly affect their durability and cost. In this review, the technical progress of key materials and components for PEMFCs has been summarized and critically discussed, including topics such as the membrane, catalyst... [more]
Green Material Prospects for Passive Evaporative Cooling Systems: Geopolymers
Zeynab Emdadi, Nilofar Asim, Mohd Ambar Yarmo, Roslinda Shamsudin, Masita Mohammad, Kamaruzaman Sopian
January 7, 2019 (v1)
Subject: Materials
Keywords: design, geopolymers, passive evaporative cooling, waste materials
Passive cooling techniques have been used mostly in countries with hot and arid climates such as Iran, Egypt, and India. However, the use of this important technology has not been seriously considered until a time of energy crisis, and consequently, environmental crisis scenarios, emerge. Scholars have renewed their interest in investigating passive cooling technology, particularly the aspects of new materials, thermal comfort, energy efficiency, new designs, climate, and environmental considerations. This review paper highlights the opportunities to use green materials, such as geopolymers, as evaporative cooling materials with different types of industrial and agricultural waste products as components. Novel ideas for passive cooling design using ancient and nature-inspired concepts are also presented to promote green technology for future applications.
Unconventional Gas: Experimental Study of the Influence of Subcritical Carbon Dioxide on the Mechanical Properties of Black Shale
Qiao Lyu, Xinping Long, Pathegama Gamage Ranjith, Yong Kang
January 7, 2019 (v1)
Subject: Materials
Keywords: Chinese shale, coring direction, mechanical properties, shale, subcritical carbon dioxide, unconventional gas
An experimental study was performed to investigate the effect of subcritical carbon dioxide (CO₂) adsorption on mechanical properties of shales with different coring directions. Uniaxial compressive strength (UCS) tests were conducted on shale samples with different CO₂ adsorption time at a pressure of 7 MPa and a temperature of 40 °C. The crack propagation and the failure mechanism of shale samples were recorded by using acoustic emission (AE) sensors together with ARAMIS technology. According to the results, samples with parallel and normal bedding angles present reductions of 26.7% and 3.0% in UCS, 30.7% and 36.7% in Young’s modulus after 10 days’ adsorption of CO₂, and 30.3% and 18.4% in UCS, 13.8% and 22.6% in Young’s modulus after 20 days’ adsorption of CO₂. Samples with a normal bedding angle presented higher brittleness index than that with a parallel bedding angle. The strain distributions show that longer CO₂ adsorption will cause higher axial strains and lateral strains. The... [more]
Zinc Porphyrins Possessing Three p-Carboxyphenyl Groups: Effect of the Donor Strength of Push-Groups on the Efficiency of Dye Sensitized Solar Cells
Ram B. Ambre, Sandeep B. Mane, Chen-Hsiung Hung
January 7, 2019 (v1)
Subject: Materials
Keywords: dye sensitized solar cell (DSSC), porphyrin sensitizer
Zinc porphyrins decorated with three p-carboxyphenyl anchoring groups and various “push” substituents of varied electron-donating strengths were prepared in good yields by facile and straightforward ways. The effect of electron-donating strength of the donor molecules on the overall power conversion efficiency was evaluated with the help of photophysical, electrochemical, photovoltaic spectroscopy and quantum chemical calculations. It is observed from the photophysical and Infrared (IR) spectroscopic data that multi-anchoring dyes are more stable and bind more strongly to the TiO₂ surface than their one-anchor counterparts. The properties like a three-step synthesis, high overall yields, possible mass production on a gram-scale and strong binding affinities with TiO₂ surfaces make them a suitable choice for commercial applications. Zn₁NH₃A, with electron donating and anti-aggregation characteristics, achieved the highest efficiency of 6.50%.
Dicyanovinyl and Cyano-Ester Benzoindolenine Squaraine Dyes: The Effect of the Central Functionalization on Dye-Sensitized Solar Cell Performance
Simone Galliano, Vittoria Novelli, Nadia Barbero, Alessandra Smarra, Guido Viscardi, Raffaele Borrelli, Frédéric Sauvage, Claudia Barolo
December 3, 2018 (v1)
Subject: Materials
Keywords: central functionalization, dye-sensitized solar cells, NIR-sensitizers, squaraines
In order to achieve a greater light absorption in the near-infrared (NIR) region with a panchromatic spectral response and to suppress the photo-isomerisation phenomenon, we herein report the design, synthesis, spectroscopic and electrochemical characterization of novel centrally functionalized symmetric benzoindolenine squaraine dyes. These molecules have shown different photoelectrical conversion properties, depending on the dicyanovinyl and cyano-ester group substitution on the squaric core unit and on the extension of the π-conjugation.
Metamaterial Absorber Comprised of Butt-Facing U-Shaped Nanoengineered Gold Metasurface
Masih Ghasemi, Pankaj Kumar Choudhury
November 28, 2018 (v1)
Subject: Materials
Keywords: complex optical mediums, metamaterial absorbers, nanostructured mediums, plasmonic resonators
The paper reports spectral features of the absorbed electromagnetic (EM) waves in a new kind of multilayered plasmonic metamaterial thin film comprised of homogenous layers of copper and silicon as the bottom and the middle sections (of the thin film), respectively, and the inhomogeneous U-shaped nanoengineered gold layer as the top. Each unit cell of the top metasurface consists of one upside and one downside U-shaped (butt-facing) structure. The absorbance of EM waves is simulated in the wavelength range of 200−1500 nm under different incidence angles considering the wave as being transmitted from the metasurface side. The low-order TE and TM modes are taken into account for the estimation of wave absorbance under varying metasurfaces as well as silicon layer thicknesses. It has been found that the nanoengineered gold layer causes higher confinement of power in silicon, which can be further controlled by suitably adjusting its thickness. Further, the increased thickness of metasurfac... [more]
Effect of Coal Rank on Various Fluid Saturations Creating Mechanical Property Alterations Using Australian Coals
Mandadige Samintha Anne Perera, Ashani Savinda Ranathunga, Pathegama Gamage Ranjith
November 28, 2018 (v1)
Subject: Materials
Keywords: CO2 saturation, coal rank, mechanical properties, N2 saturation, water saturation
During CO₂ sequestration in deep coal seams, the coal mass may be subjected to various fluid (CO₂, N₂, etc.) saturations. Therefore, in order to maintain the long-term integrity of the process, it is necessary to identify the mechanical responses of preferable coal seams for various fluid saturations. To date, many studies have focused on the CO₂ saturation effect on coal mass strength and less consideration has been given to the influence of other saturation mediums. Hence, this study aims to investigate coal’s mechanical responses to water and N₂ saturations compared to CO₂ saturation and to determine the effect of coal-rank. A series of unconfined compressive strength (UCS) tests was conducted on Australian brown and black coal samples saturated with water and N₂ at various saturation pressures. An advanced acoustic emission (AE) system was utilized to identify the changes in crack propagation behaviors under each condition. According to the results, both CO₂ and water act similarly... [more]
High Stable, Transparent and Conductive ZnO/Ag/ZnO Nanofilm Electrodes on Rigid/Flexible Substrates
Qiaoxia Zhang, Yanghua Zhao, Zhenhong Jia, Zhengfei Qin, Liang Chu, Jianping Yang, Jian Zhang, Wei Huang, Xing’ao Li
November 28, 2018 (v1)
Subject: Materials
Keywords: flexible, oxidization-induced effect, transparent electrode, ZnO/Ag/ZnO
Here, highly transparent, conductive, and stable ZnO/Ag/ZnO electrodes on transparent rigid glass and flexible substrates were prepared by facile, room-temperature magnetron sputtering, in which the continuous Ag layers were obtained by means of oxidization-induced effect under an Ar atmosphere with tiny amounts of O₂. The results showed an appropriate amount of O₂ was beneficial to form continuous Ag films because of the adsorption of oxygen between the ZnO and Ag layers. When the concentration of O₂ in the Ar atmosphere was 2.0%⁻3.0%, ZnO (40 nm)/Ag (10 nm)/ZnO (40 nm) films on rigid glass showed visible-range transmittance of 94.8% and sheet resistance of 8.58 Ω·sq−1, while the corresponding data on flexible PET substrates were 95.9% and 8.11 Ω·sq−1, respectively. In addition, the outstanding electrodes remained stable for more than six months under air conditioned conditions. The electrodes are fully functional as universal rigid/flexible electrodes for high-performance electronic... [more]
Controlled Al3+ Incorporation in the ZnO Lattice at 188 °C by Soft Reactive Co-Sputtering for Transparent Conductive Oxides
Salvatore Sanzaro, Antonino La Magna, Emanuele Smecca, Giovanni Mannino, Giovanna Pellegrino, Enza Fazio, Fortunato Neri, Alessandra Alberti
November 28, 2018 (v1)
Subject: Materials
Keywords: Al doped ZnO (AZO), co-sputtering, doping, dye-sensitized solar cells (DSCs), low temperature, transparent conductive oxide (TCO)
Transparent conductive oxide (TCO) layers, to be implemented in photo-anodes for dye-sensitized solar cells (DSCs), were prepared by co-deposition of ZnO and Al using pulsed-direct current (DC)-magnetron reactive sputtering processes. The films were deposited at low deposition temperatures (RT-188 °C) and at fixed working pressure (1.4 Pa) using soft power loading conditions to avoid intrinsic extra-heating. To compensate the layer stoichiometry, O₂ was selectively injected close to the sample in a small percentage (Ar:O₂ = 69 sccm:2 sccm). We expressly applied the deposition temperature as a controlling parameter to tune the incorporation of the Al3+ species in the targeted position inside the ZnO lattice. With this method, Aluminum-doped Zinc Oxide films (ZnO:Al) were grown following the typical wurtzite structure, as demonstrated by X-ray Diffraction analyses. A combination of micro-Raman, X-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry (SE) analyses has shown... [more]
A Multi-Component Additive to Improve the Thermal Stability of Li(Ni1/3Co1/3Mn1/3)O₂-Based Lithium Ion Batteries
Qingsong Wang, Lihua Feng, Jinhua Sun
November 28, 2018 (v1)
Subject: Materials
Keywords: electrolyte, lithium ion battery (LIB) safety, multi-component (MC) additive, thermal stability
To improve the safety of lithium ion batteries, a multi-component (MC) additive (consisting of vinylene carbonate (VC), 1,3-propylene sulfite (PS) and dimethylacetamide (DMAC)) is used in the baseline electrolyte (1.0 M LiPF₆/ethylene carbonate (EC) + diethyl carbonate (DEC)). The electrolyte with the MC additive is named safety electrolyte. The thermal stabilities of fully charged Li(Ni1/3Co1/3Mn1/3)O₂ (NCM) mixed with the baseline electrolyte and safety electrolyte, respectively, are investigated using a C80 micro-calorimeter. The electrochemical performances of the NCM/baseline electrolyte/Li and NCM/safety electrolyte/Li half cells are evaluated using galvanostatic charge/discharge, cyclic voltammetry and alternating current (AC) impedance. The experimental results demonstrate that the fully charged NCM-safety electrolyte system releases less heat and reduces the main sharp exothermic peak value to a great extent, with a reduction of 40.6%. Moreover, the electrochemical performance... [more]
A Computational Analysis of Functionally Graded Anode in Solid Oxide Fuel Cell by Involving the Correlations of Microstructural Parameters
Chao Wang
November 28, 2018 (v1)
Subject: Materials
Keywords: conventional non-graded electrodes, functionally graded electrodes (FGEs), microstructural parameters correlations, numerical simulation, solid oxide fuel cells (SOFCs)
Functionally-graded electrodes (FGEs) have shown great potential in improving solid oxide fuel cells’ (SOFCs) performance. In order to produce predictions of real FGE operations, a comprehensive numerical model that takes into account all the microstructure parameters, together with two sub model correlations, i.e., porosity-tortuosity, and porosity-particle size ratio, is utilized, aiming to provide a novel approach to demonstrate the advantages of FGEs for SOFCs. Porosity grading and particle size grading are explored by using this implemented model as a baseline. Multiple types of grading cases are tested in order to study the FGEs at a micro-scale level. Comparison between the FGEs and conventional non-graded electrodes (uniform random composites) is conducted to investigate the potential of FGEs for SOFCs. This study essentially focuses on presenting a new perspective to examine the real-world FGEs performance by involving the correlations of physically connected micro-structural... [more]
Low-Temperature, Chemically Grown Titanium Oxide Thin Films with a High Hole Tunneling Rate for Si Solar Cells
Yu-Tsu Lee, Fang-Ru Lin, Ting-Chun Lin, Chien-Hsun Chen, Zingway Pei
November 28, 2018 (v1)
Subject: Materials
Keywords: band alignment, chemically grown, heterojunction, hole tunneling, titanium oxide
In this paper, we propose a chemically grown titanium oxide (TiO₂) on Si to form a heterojunction for photovoltaic devices. The chemically grown TiO₂ does not block hole transport. Ultraviolet photoemission spectroscopy was used to study the band alignment. A substantial band offset at the TiO₂/Si interface was observed. X-ray photoemission spectroscopy (XPS) revealed that the chemically grown TiO₂ is oxygen-deficient and contains numerous gap states. A multiple-trap-assisted tunneling (TAT) model was used to explain the high hole injection rate. According to this model, the tunneling rate can be 10⁵ orders of magnitude higher for holes passing through TiO₂ than for flow through SiO₂. With 24-nm-thick TiO₂, a Si solar cell achieves a 33.2 mA/cm² photocurrent on a planar substrate, with a 9.4% power conversion efficiency. Plan-view scanning electron microscopy images indicate that a moth-eye-like structure formed during TiO₂ deposition. This structure enables light harvesting for a high... [more]
Cobalt-Based Electrolytes for Dye-Sensitized Solar Cells: Recent Advances towards Stable Devices
Federico Bella, Simone Galliano, Claudio Gerbaldi, Guido Viscardi
November 27, 2018 (v1)
Subject: Materials
Keywords: cobalt complex, cobalt electrolyte, dye-sensitized solar cell, polymer electrolyte, quasi-solid electrolyte, stability
Redox mediators based on cobalt complexes allowed dye-sensitized solar cells (DSCs) to achieve efficiencies exceeding 14%, thus challenging the emerging class of perovskite solar cells. Unfortunately, cobalt-based electrolytes demonstrate much lower long-term stability trends if compared to the traditional iodide/triiodide redox couple. In view of the large-scale commercialization of cobalt-based DSCs, the scientific community has recently proposed various approaches and materials to increase the stability of these devices, which comprise gelling agents, crosslinked polymeric matrices and mixtures of solvents (including water). This review summarizes the most significant advances recently focused towards this direction, also suggesting some intriguing way to fabricate third-generation cobalt-based photoelectrochemical devices stable over time.
Fabrication and Characterization of CH₃NH₃PbI3−x−yBrxCly Perovskite Solar Cells
Atsushi Suzuki, Hiroshi Okada, Takeo Oku
November 27, 2018 (v1)
Subject: Materials
Keywords: crystal structure, microstructure, perovskite, photovoltaic property, solar cell
Fabrication and characterization of CH₃NH₃PbI3−x−yBrxCly perovskite solar cells using mesoporous TiO₂ as electron transporting layer and 2,2′,7,7′-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9′-spirobifluorene as a hole-transporting layer (HTL) were performed. The purpose of the present study is to investigate role of halogen doping using iodine (I), bromine (Br) and chlorine (Cl) compounds as dopant on the photovoltaic performance and microstructures of CH₃NH₃PbI3−x−yBrxCly perovskite solar cells. The X-ray diffraction identified a slight decrease of crystal spacing in the perovskite crystal structure doped with a small amount of I, Br, and Cl in the perovskite compounds. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) showed the perovskite crystal behavior depended on molar ratio of halogen of Pb, I, Br and Cl. Incorporation of the halogen doping into the perovskite crystal structure improved photo generation, carrier diffusion without carrier recombina... [more]
Chemical Analysis of Different Parts of Date Palm (Phoenix dactylifera L.) Using Ultimate, Proximate and Thermo-Gravimetric Techniques for Energy Production
Ramadan A. Nasser, Mohamed Z. M. Salem, Salim Hiziroglu, Hamad A. Al-Mefarrej, Ahmed S. Mohareb, Manawwer Alam, Ibrahim M. Aref
November 27, 2018 (v1)
Subject: Materials
Keywords: date palm, Energy, proximate analysis, thermo-gravimatric analysis, ultamiate analysis
The objective of the study was to analyze chemical structure of date palm (Phoenix dactylifera L.) by employing ultimate, proximate and thermo-gravimetric techniques. Samples from different anatomical parts of date palm, namely trunk, frond base, frond midrib, leaflets, coir, fruit stem, date stone, and fruit empty bunches were considered for the experiments. Based on the findings in this work palm leaflet samples gave the highest amount of extractives content (32.9%), followed by date palm stone specimens with 31.5%. Cellulose content values of 32.8% and 47.5% were obtained for date palm stone and palm coir samples, respectively. Overall the hemicellulose contents of all samples were relatively similar to those of typical wood or non-wood lignocellulosic materials with the two exceptions of palm coir and palm leaflets. Both palm coir and palm leaflet specimens had 12.6% and 16.1% hemicellulose content. Volatile matter values of 74.3% and 87.5% were determined for leaflets and fruit em... [more]
Lithium Ion Batteries—Development of Advanced Electrical Equivalent Circuit Models for Nickel Manganese Cobalt Lithium-Ion
Alexandros Nikolian, Yousef Firouz, Rahul Gopalakrishnan, Jean-Marc Timmermans, Noshin Omar, Peter van den Bossche, Joeri van Mierlo
November 27, 2018 (v1)
Subject: Materials
Keywords: begin of life (BoL) parameters, cell characterization, dynamic discharge pulse test (DDPT), equivalent circuit model (ECM), lithium ion, Modelling, nickel manganese cobalt (NMC), validation profile, worldwide harmonized light vehicle test procedure (WLTC)
In this paper, advanced equivalent circuit models (ECMs) were developed to model large format and high energy nickel manganese cobalt (NMC) lithium-ion 20 Ah battery cells. Different temperatures conditions, cell characterization test (Normal and Advanced Tests), ECM topologies (1st and 2nd Order Thévenin model), state of charge (SoC) estimation techniques (Coulomb counting and extended Kalman filtering) and validation profiles (dynamic discharge pulse test (DDPT) and world harmonized light vehicle profiles) have been incorporated in the analysis. A concise state-of-the-art of different lithium-ion battery models existing in the academia and industry is presented providing information about model classification and information about electrical models. Moreover, an overview of the different steps and information needed to be able to create an ECM model is provided. A comparison between begin of life (BoL) and aged (95%, 90% state of health) ECM parameters (internal resistance (Ro), pola... [more]
How the Starting Precursor Influences the Properties of Polycrystalline CuInGaSe₂ Thin Films Prepared by Sputtering and Selenization
Greta Rosa, Alessio Bosio, Daniele Menossi, Nicola Romeo
November 27, 2018 (v1)
Subject: Materials
Keywords: Cu(In,Ga)Se2 (CIGS), precursors, sputtering, thin-film solar cell
Cu(In,Ga)Se₂ (CIGS)/CdS thin-film solar cells have reached, at laboratory scale, an efficiency higher than 22.3%, which is one of the highest efficiencies ever obtained for thin-film solar cells. The research focus has now shifted onto fabrication processes, which have to be easily scalable at an industrial level. For this reason, a process is highlighted here which uses only the sputtering technique for both the absorber preparation and the deposition of all the other materials that make up the cell. Particular emphasis is placed on the comparison between different precursors obtained with either In₂Se₃ and Ga₂Se₃ or InSe and GaSe as starting materials. In both cases, the precursor does not require any heat treatment, and it is immediately ready to be selenized. The selenization is performed in a pure-selenium atmosphere and only lasts a few minutes at a temperature of about 803 K. Energy conversion efficiencies in the range of 15%⁻16% are reproducibly obtained on soda-lime glass (SLG... [more]
Inorganic p-Type Semiconductors: Their Applications and Progress in Dye-Sensitized Solar Cells and Perovskite Solar Cells
Ming-Hsien Li, Jun-Ho Yum, Soo-Jin Moon, Peter Chen
November 27, 2018 (v1)
Subject: Materials
Keywords: charge selective material, charge transport material, dye-sensitized solar cell, inorganic material, p-type semiconductor, perovskite solar cell
Considering the increasing global demand for energy and the harmful ecological impact of conventional energy sources, it is obvious that development of clean and renewable energy is a necessity. Since the Sun is our only external energy source, harnessing its energy, which is clean, non-hazardous and infinite, satisfies the main objectives of all alternative energy strategies. With attractive features, i.e., good performance, low-cost potential, simple processibility, a wide range of applications from portable power generation to power-windows, photoelectrochemical solar cells like dye-sensitized solar cells (DSCs) represent one of the promising methods for future large-scale power production directly from sunlight. While the sensitization of n-type semiconductors (n-SC) has been intensively studied, the use of p-type semiconductor (p-SC), e.g., the sensitization of wide bandgap p-SC and hole transport materials with p-SC have also been attracting great attention. Recently, it has been... [more]
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