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The stability of hybrid organic-inorganic halide perovskite semiconductors remains a significant obstacle to their application in photovoltaics. To this end, the use of low-dimensional (LD) perovskites, which incorporate hydrophobic organic moieties, provides an effective strategy to improve their stability, yet often at the expense of their performance. To address this limitation, supramolecular engineering of noncovalent interactions between organic and inorganic components has shown potential by relying on hydrogen bonding and conventional van der Waals interactions. Here, the capacity to access novel LD perovskite structures that uniquely assemble through unorthodox S-mediated interactions is explored by incorporating benzothiadiazole-based moieties. The formation of S-mediated LD structures is demonstrated, including one-dimensional (1D) and layered two-dimensional (2D) perovskite phases assembled via chalcogen bonding and S-π interactions. This involved a combination of techniques, such as single crystal and thin film X-ray diffraction, as well as solid-state NMR spectroscopy, complemented by molecular dynamics simulations, density functional theory calculations, and optoelectronic characterization, revealing superior conductivities of S-mediated LD perovskites. The resulting materials are applied in n-i-p and p-i-n perovskite solar cells, demonstrating enhancements in performance and operational stability that reveal a versatile supramolecular strategy in photovoltaics.
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Background: The incidence of synchronous multiple primary lung cancer (SMPLC) is increasing, occurring in up to 20% of lung cancer patients. Accurately identifying SMPLC can be challenging, and failure to recognize SMPLC results in poor outcomes. We sought to assess the staging accuracy of patients with SMPLC at our tertiary institution. Methods: We retrospectively reviewed all patients who were evaluated for lung cancer resection between January 2018 to September 2019. Patients with SMPLC were identified using the modified Martini-Melamed criteria. Preoperative imaging, clinical assessment, and pathologic interpretation were reviewed and compared to the final staging assigned by a multidisciplinary lung cancer tumor board to determine accuracy. Results: Out of 227 patients presenting for lung cancer resection, 47 patients with 119 SMPLC were identified, of which 38 (80.9%) were incorrectly staged by at least one report. Incorrect staging was most common by computed tomography (CT) reports (n=33/47, 70.2%), followed by positron emission tomography-CT (PET-CT) reports (n=28/45, 62.2%), surgeons' clinical assessment (n=10/47, 21.3%), and histopathology reports (n=8/47, 17.0%). CT reports, when incorrect, under-staged 97.0% (n=32) of patients. PET-CT reports, when incorrect, over-staged 25.0% (n=7) of patients by reporting the second primary nodule to be "consistent with metastasis". Histopathology reports, when incorrect, over-staged 87.5% (n=7) of patients despite lack of lymph node involvement. Conclusions: Patients with SMPLC are at risk of receiving incorrect treatment based on radiographic and histopathologic staging reports alone. The observed staging inaccuracies are concerning, necessitating increased awareness among physicians caring for lung cancer patients.
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Formamidinium lead trioiodide (FAPbI3) is a promising perovskite for single-junction solar cells. However, FAPbI3 is metastable at room temperature and can cause intrinsic quantum confinement effects apparent through a series of above-bandgap absorption peaks. Here, we explore three common solution-based film-fabrication methods, neat N,N-dimethylformamide (DMF)-dimethyl sulfoxide (DMSO) solvent, DMF-DMSO with methylammonium chloride, and a sequential deposition approach. The latter two offer enhanced nucleation and crystallization control and suppress such quantum confinement effects. We show that elimination of these absorption features yields increased power conversion efficiencies (PCEs) and short-circuit currents, suggesting that quantum confinement hinders charge extraction. A meta-analysis of literature reports, covering 244 articles and 825 photovoltaic devices incorporating FAPbI3 films corroborates our findings, indicating that PCEs rarely exceed a 20% threshold when such absorption features are present. Accordingly, ensuring the absence of these absorption features should be the first assessment when designing fabrication approaches for high-efficiency FAPbI3 solar cells.
RESUMEN
Metal halide perovskite based tandem solar cells are promising to achieve power conversion efficiency beyond the theoretical limit of their single-junction counterparts. However, overcoming the significant open-circuit voltage deficit present in wide-bandgap perovskite solar cells remains a major hurdle for realizing efficient and stable perovskite tandem cells. Here, a holistic approach to overcoming challenges in 1.8 eV perovskite solar cells is reported by engineering the perovskite crystallization pathway by means of chloride additives. In conjunction with employing a self-assembled monolayer as the hole-transport layer, an open-circuit voltage of 1.25 V and a power conversion efficiency of 17.0% are achieved. The key role of methylammonium chloride addition is elucidated in facilitating the growth of a chloride-rich intermediate phase that directs crystallization of the desired cubic perovskite phase and induces more effective halide homogenization. The as-formed 1.8 eV perovskite demonstrates suppressed halide segregation and improved optoelectronic properties.
RESUMEN
Formamidinium lead triiodide (FAPbI3) is the leading candidate for single-junction metal-halide perovskite photovoltaics, despite the metastability of this phase. To enhance its ambient-phase stability and produce world-record photovoltaic efficiencies, methylenediammonium dichloride (MDACl2) has been used as an additive in FAPbI3. MDA2+ has been reported as incorporated into the perovskite lattice alongside Cl-. However, the precise function and role of MDA2+ remain uncertain. Here, we grow FAPbI3 single crystals from a solution containing MDACl2 (FAPbI3-M). We demonstrate that FAPbI3-M crystals are stable against transformation to the photoinactive δ-phase for more than one year under ambient conditions. Critically, we reveal that MDA2+ is not the direct cause of the enhanced material stability. Instead, MDA2+ degrades rapidly to produce ammonium and methaniminium, which subsequently oligomerizes to yield hexamethylenetetramine (HMTA). FAPbI3 crystals grown from a solution containing HMTA (FAPbI3-H) replicate the enhanced α-phase stability of FAPbI3-M. However, we further determine that HMTA is unstable in the perovskite precursor solution, where reaction with FA+ is possible, leading instead to the formation of tetrahydrotriazinium (THTZ-H+). By a combination of liquid- and solid-state NMR techniques, we show that THTZ-H+ is selectively incorporated into the bulk of both FAPbI3-M and FAPbI3-H at â¼0.5 mol % and infer that this addition is responsible for the improved α-phase stability.
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Resting membrane potential (RMP) and intracellular Ca2+ concentration [(Ca2+)i] are involved in tumorigenesis and metastasis. The present study investigated whether functional cardiac Na+ channels are expressed in human melanoma cells (WM 266-4) and its nonmalignant human melanocytes (HMC), as well as whether they participate in RMP maintenance and Ca2+ homeostasis. Confocal microscopy and western blot analysis were used to detect Na+ channels. The patch-clamp technique was employed to record Na+ currents and action potentials. Cytoplasmic Ca2+ was measured by loading Fluo-4. Cardiac (Nav1.5) Na+ channels were expressed in HMCs and WM 266-4 cells. Tetrodotoxin (TTX) dose-dependently blocked Na+ currents in WM 266-4 while HMCs had no Na+ currents. Ultraviolet light induced similar action potentials in HMCs and WM 266-4 cells, which were abolished by transient receptor potential A1 channel-specific blocker, HC-030031. Compared with HMCs, RMP was substantially depolarized in WM 266-4. TTX hyperpolarized RMP in WM 266-4 cells at a concentration of 30 µM, which facilitated Ca2+ influx. Compared with HMCs, (Ca2+)i was significantly higher in WM 266-4 cells and was elevated by 30 µM TTX. Collectively, Cardiac Na+ channels depolarize RMP and inhibit Ca2+ uptake in melanoma cells possibly contributing to tumorigenesis and metastasis. Na+ channel agonists may be developed to treat melanoma such as WM 266-4.
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INTRODUCTION: Programmed death ligand 1 (PD-L1) testing of non-small cell lung cancer (NSCLC) specimens helps select patients most likely to respond to immune checkpoint inhibitors. PD-L1 immunohistochemical testing is approved for formalin-fixed, paraffin-embedded (FFPE) surgical pathology specimens; however, the testing performance on FFPE cytology cell block specimens is unknown. MATERIALS AND METHODS: The study is a retrospective cohort analysis of advanced stage NSCLC patients treated at our institution where tumor PD-L1 expression using the clone 22C3 pharmDx kit on the Dako Automated Link 48 platform was performed on either cytology cell block or surgical pathology specimens. Concomitant tumor mutation biomarkers were also collected, as well as tumor clinicopathologic characteristics and clinical outcome data following pembrolizumab treatment. RESULTS: 232 patient tumor specimens were tested for PD-L1 expression (94 on cytology cell block and 138 on surgical pathology specimens). No significant differences in PD-L1 tumor proportion score (TPS) were observed between cytology and surgical pathology groups, with both patient cohorts containing ~35% of tumors showing TPS ≥50%. Although few in number, patients with PD-L1 TPS ≥50% based on cytology vs. surgical pathology who received treatment with pembrolizumab demonstrated similar response and disease control rates. CONCLUSIONS: In this cohort of advanced NSCLC patients with standard of care PD-L1 testing performed on either FFPE cytology cell blocks or FFPE surgical pathology specimens, similar patterns were observed in population tumor PD-L1 expression patterns, concomitant driver mutations, and clinical response to palliative pembrolizumab in selected patients with TPS ≥50%.