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In this research, SCAPS-1D simulation software (Version: 3.3.10) was employed to enhance the efficiency of CsSnX[sub.3] (X = Cl, Br, I) all-inorganic perovskite solar cells. By fine-tuning essential parameters like the work function of the conductive glass, the back contact point, defect density, and the thickness of the light absorption layer, we effectively simulated the optimal performance of CsSnX[sub.3] (X = Cl, Br, I) all-inorganic perovskite solar cells under identical conditions. The effects of different X-site elements on the overall performance of the device were also explored. The theoretical photoelectric conversion efficiency of the device gradually increases with the successive substitution of halogen elements (Cl, Br, I), reaching 6.09%, 17.02%, and 26.74%, respectively. This trend is primarily attributed to the increasing size of the halogen atoms, which leads to better light absorption and charge transport properties, with iodine (I) yielding the highest theoretical conversion efficiency. These findings suggest that optimizing the halogen element in CsSnX[sub.3] can significantly enhance device performance, providing valuable theoretical guidance for the development of high-efficiency all-inorganic perovskite solar cells.

Antimony selenide (Sb[sub.2]Se[sub.3]) material has drawn considerable attention as an Earth-abundant and non-toxic photovoltaic absorber. The power conversion efficiency of Sb[sub.2]Se[sub.3]-based solar cells increased from less than 2% to over 10% in a decade. Different deposition methods were implemented to synthesize Sb[sub.2]Se[sub.3] thin films, and various device structures were tested. In search of a more environmentally friendly device composition, the common CdS buffer layer is being replaced with oxides. It was identified that on oxide substrates such as TiO[sub.2] using vacuum-based close-space deposition methods, an intermediate deposition step was required to produce high-quality thin films. However, little or no investigation was carried out using another very successful vacuum deposition approach in Sb[sub.2]Se[sub.3] technology called vapour transport deposition (VTD). In this work, we present optimized VTD process conditions to achieve compact, pinhole-free, ultra-thin (<400 nm) Sb[sub.2]Se[sub.3] absorber layers. Three process steps were designed to first deposit the seed layer, then anneal it and, at the final stage, deposit a complete Sb[sub.2]Se[sub.3] absorber. Fabricated solar cells using absorbers as thin as 400 nm generated a short-circuit current density over 30 mA/cm[sup.2], which demonstrates both the very high absorption capabilities of Sb[sub.2]Se[sub.3] material and the prospects for ultra-thin solar cell application.

In this work, CdSe.sub.xS.sub.1-x QDs with X different value and compositions were prepared for utilization as light absorbing in the CdS/CdSe.sub.xS.sub.1-x multiple quantum dot-sensitized solar cells. These QDs with X different value were deposited on the FTO/TiO.sub.2NPs/CdS/CdSe.sub.XS.sub.1-X/ZnS photoanode through the successive ionic layer absorption and reaction (SILAR) method. Then the photovoltaic parameters were measured and extracted by different photovoltaic analyses. The X value was altered in the range of 0.1-0.4, and the corresponding cells were fabricated. According to the results, the best efficiency was achieved for the QDSCs with CdSe.sub.XS.sub.1-X, X = 0.3, light absorbing layer. The efficiency was increased about 39% compared to the reference CdSe.sub.xS.sub.1-x free cell. The process of synthesis and deposition of CdSe.sub.XS.sub.1-X QDs was carried out in 5 cycles. In the following, the number of SILAR cycles was optimized for the X appropriate ratio. According to measurements, the FTO/TiO.sub.2NPs/CdS/CdSe.sub.0.3S.sub.0.7/ZnS photoanode structure with the CdSe.sub.0.3S0.sub..7 layer deposited in 3 SILAR cycles, created and efficiency enhancement about 38% compared to the pervious maximum state. The IPCE curves were measured, and corresponding APCEs were extracted which showed a maximum quantum conversion efficiency about 75%, while the spectrum is spread in the wavelength range of 400-700 nm. This improvement in photovoltaic characteristics can be attributed to the broader light absorption region and higher light-harvesting efficiency. Besides, due to the performed calculations a cascade energy band diagram is formed between the CdS and CdSeS sensitizing layers which is suitable for well transfer of photogenerated electron-hole pair.

Recently, wind electrical power systems are getting a lot of attention since they are cost competitive, environmentally clean, and safe renewable power source as compared with the fossil fuel and nuclear power generation. A special type of induction generator, called a doubly fed induction generator (DFIG), is used extensively for high-power wind applications. They are used more and more in wind turbine applications due to the ease of controllability, the high energy efficiency, and the improved power quality.This research aims to develop a method of a field orientation scheme for control both, the active and the reactive powers of a DFIG that are driven by a wind turbine. Also, the dynamic model of the DFIG, driven by a wind turbine during grid faults, is analyzed and developed, using the method of symmetrical components. Finally, this study proposes a novel fault ride-through (FRT) capability with a suitable control strategy (i.e. the ability of the power system to remain connected to the grid during faults). Auszug aus dem Text Text Sample: Chapter 2.1, Introduction: Electrical power is the most widely used source of energy for our homes, work places and industries. Population and industrial growth have led to significant increases in power consumption over the past three decades. Natural resources like coal, petroleum and gas which drive our power plants, industries and vehicles for many decades are becoming depleted at a very fast rate. This serious issue has motivated nations across the world to think about alternative forms of energy which utilize inexhaustible natural resources. Wind plants have benefited from steady advances in technology made over past 15 years. Much of the advancement has been made in the components dealing with grid integration, the electrical machine, power converters, and control capability. The days of the simple induction machine with soft start are long gone. We are now able to control the real and reactive power of the machine, limit power output and control voltage and speed [1]. There is a lot of research going on around the world in this area and technology is being developed that offers great deal of capability. It requires an understanding of power systems, machines and applications of power electronic converters and control schemes put together on a common platform. Unlike a conventional power plant that uses synchronous generators, a wind turbine can operate as fixed-speed or variable-speed. In a fixed-speed wind turbine, the stator of the generator is directly connected to the grid. However, in a variable-speed wind turbine, the machine is controlled and connected to the power grid through a power electronic converter. There are various reasons for using a variable-speed wind turbine: i. Variable-speed wind turbines offer a higher energy yield in comparison to constant speed turbines. ii. The reduction of mechanical loads and simple pitch control can be achieved by variable speed operation. iii. Variable-speed wind turbines offer acoustic noise reduction and extensive controllability of both active and reactive power. iv. Variable-speed wind turbines show less fluctuation in the output power [1] and [2]. The use of renewable energy sources for electric power generation is gaining importance in order to reduce global warming and environmental pollution, this is in addition to meeting the escalating power demand of the consumers. Among various renewable energy technologies, grid integration of wind energy electric conversion system is being installed in huge numbers due to their clean and economical energy conversion. Recent advancements in wind turbine technology and power electronic systems are also more instrumental for the brisk option of grid integration of wind energy conversion system [3]. Generally, wind power generation uses either fixed speed or variable speed turbines, the main configurations of generators and converters used for grid connected variable speed wind power system (WPS) are presented in the following sections: 2.2, Synchronous Generators Driven by a Wind Turbine: A synchronous generator usually consist of a stator holding a set of three-phase windings, which supplies the external load, and a rotor that provides a source of magnetic field. The rotor may be supplied either from permanent magnetic or from a direct current flowing in a wound field. 2.2.1, Wound Field Synchronous Generator (WFSG) Driven by a Wind Turbine: The stator winding is connected to network through a four-quadrant power converter comprised of two back-to-back sinusoidal PWM. The machine side converter regulates the electromagnetic torque, while the grid side converter regulates the real and reactive power delivered by the WPS to the utility. The Wound Field Synchronous Generator has some advantages that are: The efficiency of this machine is usually high, because it employs the whole stator current for the electromagnetic torque production [3]. The main benefit of the employment of wound field synchronous generator with salient pole is that it allows the direct control of the power factor of the machine, consequently the stator current may be minimized at any operation circumstances. The existence of a winding circuit in the rotor may be a drawback as compared with permanent magnet synchronous generator. In addition, to regulate the active and reactive power generated, the converter must be sized typically 1.2 times of the WPS rated power [4]. 2.2.2, Permanent-Magnet Synchronous Generator (PMSG) Driven by a Wind Turbine: Many configuration schemes using a permanent magnet synchronous generator for power generation had been adopted. In one of them a permanent magnet synchronous generator was connected to a three-phase rectifier followed by boost converter. In this case, the boost converter controls the electromagnet torque. One drawback of this configuration is the use of diode rectifier that increases the current amplitude and distortion of the PMSG [5]. As a result this configuration has been considered for small size wind power system (WPS) (smaller than 50 kW). In another scheme using PMSG, the PWM rectifier is placed between the generator and the DC link, while another PWM inverter is connected to the network. The advantage of this system regarding the use of field orientation control (FOC) is that it allows the generator to operate near its optimal working point in order to minimize the losses in the generator and power electronic circuit. However, the performance is dependent on the good knowledge of the generator parameter that varies with temperature and frequency. The main drawbacks, in the use of PMSG, are the cost of permanent magnet that increase the price of machine, demagnetization of the permanent magnet material and it is not possible to control the power factor of the machine [6]. Biographische Informationen Mohmoud Mossa has been teaching undergraduate courses in electrical engineering at the Faculty of engineering, Minia University, Egypt since 2009. Thereby, he specializes in electrical machine, electrical machines and control laboratory, control, power electronics, PLC programming and applications, protection, and electronic measurements. The author is the trainer and supervisor of the Lab. of Tractions and Drives (Siemens Lab), and supports professors in the design of projects, and the in the supervision of students. Further, Mohmoud Mossa is the author of several publications. For instance, he has published research papers that are entitled 'Enhancement of Fault Ride Through Capability of Wind Driven DFIG Connected to the Grid' published by the Journal of Engineering Sciences, 'Novel Scheme for Improving the Performance of a Wind Driven DFIG During Grid Fault' published by the multi-science publishing website, and 'Field Orientation Control of a Wind Driven DFIG Connected to the Grid' that was published by the WSEAS publishing academy.

Planar perovskite solar cells (PSCs), as a promising photovoltaic technology, have been extensively studied, with strong expectations for commercialization. Improving the power conversion efficiency (PCE) of PSCs is necessary to accelerate their practical application, in which the electron transport layer (ETL) plays a key part. Herein, a single-anchored ligand of phenylphosphonic acid (PPA) is utilized to regulate the chemical bath deposition of a TiO[sub.2] ETL, further improving the PCE of planar PSCs. The PPA possesses a steric benzene ring and a phosphoric acid group, which can inhibit the particle aggregation of the TiO[sub.2] film through steric hindrance, leading to optimized interface (ETL/perovskite) contact. In addition, the incorporated PPA can induce the upshift of the Fermi-level of the TiO[sub.2] film, which is beneficial for interfacial electron transport. As a consequence, the PSCs with PPA-TiO[sub.2] achieve a PCE of 24.83%, which is higher than that (24.21%) of PSCs with TiO[sub.2]. In addition, the unencapsulated PSCs with PPA-TiO[sub.2] also exhibit enhanced stability when stored in ambient conditions.

In this work, hydrogenated amorphous silicon carbide (a-SiC[sub.x]:H) and hydrogenated amorphous silicon oxide (a-SiO[sub.x]:H) films with similar optical bandgaps (E [sub.g]), refractive indices (n), and extinction coefficients (k) were fabricated using pulse-wave modulation (PWM) plasma technology by controlling the plasma turn-on to turn-off time ratio (t [sub.on]/t [sub.off]). These films were placed at the 1/5 position of the p/i and i/n interfaces of hydrogenated amorphous silicon (a-Si:H) p-i-n solar cells to investigate their influence on solar cell performance. The experimental results confirmed that the deviations in E [sub.g], n, and k were controlled to within 0.2%, 1.4%, and 4.1%, respectively. Under these conditions, placing a-SiC[sub.x]:H and a-SiO[sub.x]:H films at the p/i and i/n interfaces successfully increased the open-circuit voltage (V [sub.oc]). However, this also led to a decrease in the short-circuit current due to valence band (ΔE [sub.v]) or conduction band (ΔE [sub.c]) offsets. The reduction in cell fill factor (FF) and efficiency (η) caused by placing a-SiC[sub.x]:H and a-SiO[sub.x]:H films at the p/i interface was greater than that caused by placing them at the i/n interface. Placing the a-SiC[sub.x]:H film at the p/i interface significantly improved the V [sub.oc] to 0.8998 V. Due to the n-type doping effect of oxygen atoms, the a-SiO[sub.x]:H film exhibited the lowest FF of 43.99% and η of 4.850% at the p/i interface; however, when placed at the i/n interface, it yielded an FF of 67.38% and an η of 7.43%, which are comparable to the standard cell. Appropriately placing the a-SiC[sub.x]:H film at the p/i interface and the slightly n-type a-SiO[sub.x]:H film at the i/n interface can effectively improve the V [sub.oc], FF, and η of p-i-n solar cells.

The evolution of photovoltaic cells is intrinsically linked to advancements in the materials from which they are fabricated. This review paper provides an in-depth analysis of the latest developments in silicon-based, organic, and perovskite solar cells, which are at the forefront of photovoltaic research. We scrutinize the unique characteristics, advantages, and limitations of each material class, emphasizing their contributions to efficiency, stability, and commercial viability. Silicon-based cells are explored for their enduring relevance and recent innovations in crystalline structures. Organic photovoltaic cells are examined for their flexibility and potential for low-cost production, while perovskites are highlighted for their remarkable efficiency gains and ease of fabrication. The paper also addresses the challenges of material stability, scalability, and environmental impact, offering a balanced perspective on the current state and future potential of these material technologies.

Perovskite (ABX[sub.3]) nanocrystals have garnered significant attention as interfacial passivation materials for perovskite solar cells (PSCs) due to their tunable optoelectronic properties. However, single-component systems often suffer from insufficient defect passivation and poor film stability, limiting their practical application. To address these challenges, we develop a MnBr[sub.2] doping strategy for CsPbBr[sub.3] nanocrystals, which enables precise control over their morphology and phase evolution via B-site Pb[sup.2+]/X-site Br[sup.−] stoichiometric regulation. Systematic doping induces a progressive morphological transition from cubic to quasi-spherical geometries, accompanied by a phase transformation from cubic CsPbBr[sub.3] to hexagonal Cs[sub.4]PbBr[sub.6]. The optimized mixed-phase nanocrystals exhibit synergistic effects in interfacial defect passivation and charge transport enhancement, leading to PSCs modified with CsPbBr[sub.3]/Cs[sub.4]PbBr[sub.6] heterostructures achieving a champion power conversion efficiency (PCE) of 23.33% along with enhanced stability. This work not only elucidates the fundamental structure–property relationships governing MnBr[sub.2]-doped nanocrystal evolution but also establishes a new materials design paradigm for high-performance PSC interfaces.