ABSTRACT
This study investigates the applicability of Principal Component Analysis (PCA) for distinguishing construction materials. The approach enhances data presentation, revealing distinct clusters and variable impacts on materials. This perspective provides valuable insights into concrete materials, guiding materials science and engineering practices. Our findings show the capacity of PCA to show a clear distinction between concrete and non-concrete composites. Compressive strength significantly affects certain composites, being influenced by aerogel loading. The peculiar role of aerogel density among the other factors is attributed to their possession of the smallest thermal conductivity. To address moderate total variance of PCA, segregation into concrete (C) and non-concrete (NC) categories is explored, offering a more robust distinction and higher clustering. Concrete materials show higher variance, emphasizing the effectiveness of the segregation approach. PCA highlights aerogel density's influence on thermal conductivity on concrete materials. For non-concrete materials, a moderately higher variance is noted, emphasizing the critical role of aerogel-related properties (size and density). These findings underscore the importance of aerogel characteristics in shaping material behaviour.
ABSTRACT
In this investigation, we employ a numerical simulation approach to model a hydrogenated lead-free Cs2AgBiBr6 double perovskite solar cell with a p-i-n inverted structure, utilizing SCAPS-1D. Contrary to traditional lead-based perovskite solar cells, the Cs2AgBiBr6 double perovskite exhibits reduced toxicity and enhanced stability, boasting a maximum power conversion efficiency of 6.37%. Given its potential for improved environmental compatibility, achieving higher efficiency is imperative for its practical implementation in solar cells. This paper offers a comprehensive quantitative analysis of the hydrogenated lead-free Cs2AgBiBr6 double perovskite solar cell, aiming to optimize its structural parameters. Our exploration involves an in-depth investigation of various electron transport layer materials to augment efficiency. Variables that affect the photovoltaic efficiency of the perovskite solar cell are closely examined, including the absorber layer's thickness and doping concentration, the hole transport layer, and the absorber defect density. We also investigate the impact of the doping concentration of the electron transport layer and the energy level alignment between the absorber and the interface on the photovoltaic output of the cell. After careful consideration, zinc oxide is chosen to serve as the electron transport layer. This optimized configuration surpasses the original structure by over four times, resulting in an impressive power conversion efficiency of 26.3%, an open-circuit voltage of 1.278 V, a fill factor of 88.21%, and a short-circuit current density of 23.30 mA.cm-2. This study highlights the critical role that numerical simulations play in improving the chances of commercializing Cs2AgBiBr6 double perovskite solar cells through increased structural optimization and efficiency.
ABSTRACT
A hybrid tin-based perovskite solar cell with p-i-n inverted structure is modeled and simulated using SCAPS. The inverted structure is composed of PEDOT:PSS (as hole transport layer-HTL)/GA0.2FA0.78SnI3-1% EDAI2 (as perovskite absorber layer)/C60-fullerene (as electron transport layer-ETL). Previous experimental studies showed that unlike conventional tin-based perovskite solar cells (PSC), the present hybrid tin-based PSC passes all harsh standard tests and generates a power conversion efficiency of only 8.3%. Despite the high stability that this material exhibits, emphasis on enhancing its power conversion efficiency (PCE) is crucial. To that end, various ETL and HTL materials have been rigorously investigated. The impact of energy level alignment between HTL/absorber and absorber/ETL interfaces have been elucidated. Moreover, the thickness and the doping concentration of all the previously mentioned layers have been varied to inspect their effect on the photovoltaic performance of the PSC. The optimized structure with CuI (copper iodide) as HTL and ZnOS (zinc oxysulphide) as ETL scored a PCE of 26%, which is more than three times greater than the efficiency of the initial structure. The current numerical simulation on GA0.2FA0.78SnI3-1% EDAI2 could greatly increase its chance for commercial development.
ABSTRACT
Formamidinium tin iodide (FASnI3)-based perovskite solar cells (PSCs) have achieved significant progress in the past several years. However, these devices still suffer from low power conversion efficiency (PCE=6%) and poor stability. Recently, Cesium (Cs)-doped Formamidinium tin iodide (FA1−xCsxSnI3) showed enhanced air, thermal, and illumination stability of PSCs. Hence, in this work, FA1−xCsxSnI3 PSCs have been rigorously studied and compared to pure FASnI3 PSCs using a solar cell capacitance simulator (SCAPS) for the first time. The aim was to replace the conventional electron transport layer (ETL) TiO2 that reduces PSC stability under solar irradiation. Therefore, FA1−xCsxSnI3 PSCs with different Cs contents were analyzed with TiO2 and stable ZnOS as the ETLs. Perovskite light absorber parameters including Cs content, defect density, doping concentration and thickness, and the defect density at the interface were tuned to optimize the photovoltaic performance of the PSCs. The simulation results showed that the device efficiency was strongly governed by the ETL material, Cs content in the perovskite and its defect density. All the simulated devices with ZnOS ETL exhibited PCEs exceeding 20% when the defect density of the absorber layer was below 1015 cm−3, and deteriorated drastically at higher values. The optimized structure with FA75Cs25SnI3 as light absorber and ZnOS as ETL showed the highest PCE of 22% with an open circuit voltage Voc of 0.89 V, short-circuit current density Jsc of 31.4 mA·cm−2, and fill factor FF of 78.7%. Our results obtained from the first numerical simulation on Cs-doped FASnI3 could greatly increase its potential for practical production.
ABSTRACT
The present study addresses the discrete simulation of the flow of concentrated suspensions encountered in the forming processes involving reinforced polymers, and more particularly the statistical characterization and description of the effects of the intense fiber interaction, occurring during the development of the flow induced orientation, on the fibers' geometrical center trajectory. The number of interactions as well as the interaction intensity will depend on the fiber volume fraction and the applied shear, which should affect the stochastic trajectory. Topological data analysis (TDA) will be applied on the geometrical center trajectories of the simulated fiber to prove that a characteristic pattern can be extracted depending on the flow conditions (concentration and shear rate). This work proves that TDA allows capturing and extracting from the so-called persistence image, a pattern that characterizes the dependence of the fiber trajectory on the flow kinematics and the suspension concentration. Such a pattern could be used for classification and modeling purposes, in rheology or during processing monitoring.
ABSTRACT
Selected transcription factors have critical roles to play in organism survival by regulating the expression of genes that control the adaptations needed to handle stress conditions. The retinoblastoma (Rb) protein coupled with the E2F transcription factor family was demonstrated to have roles in controlling the cell cycle during freezing and associated environmental stresses (anoxia, dehydration). Rb phosphorylation or acetylation at different sites provides a mechanism for repressing cell proliferation that is under the control of E2F transcription factors in animals facing stresses that disrupt cellular energetics or cell volume controls. Other central regulators of the cell cycle including Cyclins, Cyclin-dependent kinases (Cdks), and checkpoint proteins detect DNA damage or any improper replication, blocking further progression of cell cycle and interrupting cell proliferation. This review provides an insight into the molecular regulatory mechanisms of cell cycle control, focusing on Rb-E2F along with Cyclin-Cdk complexes typically involved in development and differentiation that need to be regulated in order to survive extreme cellular stress.
