The performance of perovskite solar cells is highly dependent on the fabrication method; thus, controlling the growth mechanism of perovskite crystals is a promising way towards increasing their efficiency and stability. Herein, a multi‐cation halide composition of perovskite solar cells is engineered via the two‐step sequential deposition method. Strikingly, it is found that adding mixtures of 1D polymorphs of orthorhombic δ‐RbPbI3 and δ‐CsPbI3 to the PbI2 precursor solution induces the formation of porous mesostructured hexagonal films. This porosity greatly facilitates the heterogeneous nucleation and the penetration of FA (formamidinium)/MA (methylammonium) cations within the PbI2 film. Thus, the subsequent conversion of PbI2 into the desired multication cubic α‐structure by exposing it to a solution of formamidinium methylammonium halides is greatly enhanced. During the conversion step, the δ‐CsPbI3 also is fully integrated into the 3D mixed cation perovskite lattice, which exhibits high crystallinity and superior optoelectronic properties. The champion device shows a power conversion efficiency (PCE) over 22%. Furthermore, these devices exhibit enhanced operational stability, with the best device retaining more than 90% of its initial value of PCE under 1 Sun illumination with maximum power point tracking for 400 h.

The impacts of halide and nonhalide sources of guanidinium cations, including guanidinium chloride (GCl) ((NH2)3CCl) and guanidinium thiocyanate (GTC) ((NH2)3CSCN), are comparatively analyzed on the structural, morphological, and photophysical properties of (CsMAFA)PbBrxI3 − x (x = 0.17) (MA = methylammonium, FA = formamidinium) perovskite films. X‐ray diffraction (XRD) reveals that the formation of photoinactive phases depends on the nature of counterions (halide vs nonhalide). Furthermore, morphological analysis shows that with the addition of guanidinium salts, the apparent grain size decreases due to the enhancement of nucleation density and/or slow growth of perovskite structures. More importantly, the introduction of GCl leads to the fabrication of perovskite solar cells (PSCs), yielding a photovoltage as high as 1.16 V (1.1 V for reference). In contrast, the introduction of GTC minimally affects the photovoltage, underlining the significance of counterions in improving the photovoltage of PSCs. The present preliminary results of the density functional theory based theoretical investigation related to the effect of G cation on the structure of the perovskite system is presented. In summary, the insights gained through structural and morphological characterization helps to understand the critical role of counterions of guanidinium salts in PSCs.

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The nasal septum is an osteocartilaginous wall that divides the nose into two nasal cavities. Asymptomatic minor deviation of the septum is considered a normal developmental variation found in the majority of the population. The reported global prevalence rates had great variation due to the extent of deviation considered in the reporting studies. Previous classification systems have been proposed to classify the nasal septal deviation according to the characteristics of the nasal septum seen horizontally and vertically. For some patients, the degree of the deviation may affect the nasal airflow causing obstruction or impairing the olfactory function. Headache, rhinosinusitis, high blood pressure, obstructive sleep apnea, and breathing sounds are also among the clinical presentations of nasal septal deviation. Clinical assessment is sufficient to make the diagnosis while imaging techniques are required for decision-making. Radiological imaging techniques such as computed tomography (CT) are used to classify and assess the severity of the deviated septum. Surgical correction is the treatment option for nasal septal deviation. Septoplasty is the most common procedure used for nasal correction with high satisfaction levels and low complication rates. In this review, we present a comprehensive summary of the concept, presentation, diagnosis, management options, and quality of life of patients with nasal septal deviation.

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