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Perovskite solar cells (PSCs) have gained tremendous research interest recently owing to several advantages, including low material cost, facile solution processability, bandgap tunability, and alluring device efficiency. The organic formamidinium (FA) cation‐based perovskites are mainly considered as one of the potential candidates for charge carrier generation due to their excellent properties, such as bandgap and thermal stability than traditional perovskites. However, the inevitable unfavorable polymorphism (i.e., α to δ) at room temperature still forms the basis for numerous research works to allow the fabrication of a high‐quality absorber and enhances the PSCs performance. The studies to resolve the polymorphism and several contemporary techniques (e.g., passivation strategy) with several recent novel fabrication methods presented in this review form the essence of the improvements in PSCs. The absorber morphology also influences the charge‐transfer behavior and the device's lifetime. Therefore, understanding these properties is essential to improve the absorber quality and avoid many defects. This review focuses on the structure and properties of pure and mixed FA perovskites with various halides, mainly the FA cation's role in the absorber composition. And a comprehensive overview of recent FA cation‐based double, triple, and quadrupole PSCs results with proper scientific explanations to understand the device physics.

In perovskite solar cells (PSCs), the charge carrier recombination obstacles mainly occur at the ETL/perovskite and HTL/perovskite interfaces, which play a decisive role in the solar cell performance. Therefore, this study aims to enhance the flexible PSC (FPSC) efficiency by adding the newly designed CBz-PAI-interlayer (simply CBz-PAI-IL) at the perovskite/HTL interface. In addition, substantial work has been carried out on five different HTLs (Se/Te–Cu2O, CuGaO2, V2O5, and CuSCN, including conventional Spiro-OMeTAD as a reference HTL with and without CBz-PAI-IL), using drift-diffusion simulation to find suitable FPSC design to attain the maximum PCE. Interestingly, PET/ITO/AZO/ZnO NWs/FACsPbBrI3/CBz-PAI/Se/Te–Cu2O/Au device architecture demonstrates the highest achievable power conversion efficiency (PCE) of 27.9 %. The findings of this study confirmed that the reference device (without IL) displays a large valence band edge (VBE)/highest occupied molecular orbital (HOMO) energy level misalignment compared to the modified interface device (with CBz-PAI-IL that reduces VBE/HOMO level mismatch) that eases the hole transport, simultaneously, it reduces the charge carrier recombinations at the interface, resulting in diminished Voc losses in the device. Furthermore, the influence of perovskite absorber thickness and defect density, parasitic resistances, and working temperature are systematically examined to govern the superior FPSC efficiency and concurrently understand the device physics.

Due to their excellent properties, Zinc oxide nanowires (ZnO NW) have been attractive and considered as a promising electron-transporting layer (ETL) in flexible Perovskite Solar Cells (FPSCs). Since the first report on ZnO NWs-based FPSCs giving 2.6 % power conversion efficiency (in 2013), great improvements have been made, allowing to reach up to∼15 % nowadays. However, some issues still need to be addressed, especially on flexible substrates, to achieve uniform and well-aligned ZnO NWs via low-cost chemical solution techniques. Several parameters, such as the growing method (time, temperature, precursors concentration), addition of seed layer (thickness, roughness, annealing temperature) and substrate (rigid or flexible), play a crucial role in ZnO NWs properties (i.e., length, diameter, density and aspect ratio). In this review, these parameters allowing to control the properties of ZnO NWs, like the growth techniques, utilization of seed layers and the growing method (time or precursors concentration) have been summarized. Then, a particular focus on the ZnO NW's role in FPSCs as well as the use of these results on the development of ZnO NWs-based FPSCs have been highlighted.

Arsenic (As) removal from portable water bodies using the nanotechnology-based adsorption technique offers a unique method to lower the As contamination below the World Health Organization’s (WHO) maximum contaminant level (MCL). This work promotes a systematic methodological-based adsorption study by optimizing the different parameters that affect As removal using TiO2/γ-Fe2O3 nanocomposites (T/M NCs) prepared with the green, facile, and cost-effective ball milling method. The studies using X-ray Diffraction (XRD) illustrate the structural modifications with variations in the constituting T/M ratios, with high-resolution transmission electron microscopy (HRTEM) being used for the NC morphological studies. The optical characterization studies showed that bandgap tuning between 2–2.8 eV reduced the maghemite (γ-Fe2O3) content in the NCs and the elemental analysis confirmed the desired stoichiometry of the NCs. The magnetic measurements showed that the magnetic interaction among the particles tends towards exchange coupling behavior as the weight ratio of γ-Fe2O3 content decreases in the NCs. The adsorption studies using the most efficient NCs with an optimized condition (NC dose (8 g/L), contact time (15 min), As concentration (2 ppm), and pH (4)) resulted in a more than 99% removal of As species, suggesting the excellent behavior of the synthesized nanomaterial for water treatment and making it more economical than other competing adsorption techniques and materials.

ABSTRACT: Aims: It has been reported that there are a certain percentage of COVID-19 patients who recover but suffer from devastating permanent organ damage or failure. Others suffer from long Covid syndrome, with prolonged symptoms that persist more than 12 weeks. However, there is scarcity of literature regarding the provision of dental treatment for these two groups of patients. This manuscript reviews the impact of multi-system involvement on the provision of dental care to these patients. Materials and methods: A search of literature was done in PubMed-Medline and Scopus databases to review the available literature on COVID-19 impacts on pulmonary, cardiovascular, haematologic, renal, gastrointestinal, endocrine, and neurologic systems and respective management in dental clinical settings. Results: The literature search from PubMed-Medline and Scopus databases resulted in 74 salient articles that contributed to the concise review on COVID-19 effects on pulmonary, cardiovascular, haematologic, renal, gastrointestinal, endocrine, and neurologic systems and/or its respective dental management recommendations. Conclusions: This concise review covers the management of post COVID-19 patients with pulmonary, cardiovascular, haematologic, renal, gastrointestinal, endocrine, or neurologic system complications.

Electron and hole transport layers (ETL and HTL) play an essential role in shaping the photovoltaic performance of perovskite solar cells. While compact metal oxide ETL have been largely explored in planar n-i-p device architectures, aligned nanowires or nanorods remain highly relevant for efficient charge extraction and directional transport. In this study, we have systematically grown ZnO nanowires (ZnO NWs) over aluminum-doped zinc oxide (AZO) substrates using a low-temperature method, hydrothermal growth (HTG). The main growth parameters were varied, such as hydrothermal precursors concentrations (zinc nitrate hexahydrate, hexamethylenetetramine, polyethylenimine) and growing time, in order to finely control NW properties (length, diameter, density, and void fraction). The results show that ZnO NWs grown on AZO substrates offer highly dense, well-aligned nanowires of high crystallinity compared to conventional substrates such as FTO, while demonstrating efficient FACsPb(IBr)3 perovskite device performance, without the requirement of conventional compact hole blocking layers. The device performances are discussed based on NW properties, including void fraction and aspect ratio (NW length over diameter). Finally, AZO/ZnO NW-based devices were fabricated with a recent HTL material based on a carbazole moiety (Cz–Pyr) and compared to the spiro-OMeTAD reference. Our study shows that the Cz–Pyr-based device provides similar performance to that of spiro-OMeTAD while demonstrating a promising stability in ambient conditions and under continuous illumination, as revealed by a preliminary aging test.

In this work, a simple thin films manufacturing process of all‐inorganic halide perovskites has been developed under ambient conditions. A flow of nitrogen placed above the freshly deposited film by spin‐coating, during the brief heat treatment stage, provides a suitable microstructure for photovoltaic applications. The main parameters of this process have been tested in order to obtain the most suitable perovskite layer for solar cells. Films of 3D CsPbI2Br, mixtures of [3D+2D] phases where Cs2PbCl2I2 is the 2D material, and in the presence of indium in order to substitute lead in the main phase, were optimized and their structures analyzed by means of scanning electron microscopy and X‐ray diffraction. Films are more compact and the structure tends to be more symmetrical upon doping, which preserve the black phase for a longer time. Each type of film was integrated into a fully functional solar cell. The addition of the 2D material to the main 3D phase affect the photovoltaic performances of the manufactured devices under our conditions but the photoactive black phase is clearly stabilized. A preferred orientation was observed in the presence of the 2D material and under nitrogen flow. Texture analysis evidenced for a fiber‐like structure and the presence of indium tends to improve the black phase stability. [ABSTRACT FROM AUTHOR]