Construction of Heterojunction-Rich Metal Nitrides Porous Nanosheets Electrocatalyst for Alkaline Water/Seawater Splitting at Large Current Density.

The exploiting electrocatalysts for water/seawater electrolysis with remarkable activity and outstanding durability at industrial grade current density remains a huge challenge. Herein, CoMoNx and Fe-doped CoMoNx nanosheet arrays are in-situ grown on Ni foam, which possess plentiful holes, multilevel heterostructure, and lavish Co5.47 N/MoN@NF and Fe-Co5.47 N/MoN@NF interfaces. They require low overpotentials of 213 and 296 mV for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) under alkaline media to achieve current density of 800 mA cm-2 , respectively, and both possess low Tafel slopes (51.1 and 49.1 mV dec-1 ) and undiminished stability over 80 h. Moreover, the coupled Co5.47 N/MoN@NF and Fe-Co5.47 N/MoN@NF electrolyzer requires low voltages of 1.735 V to yield 500 mA cm-2 in alkaline water. Notably, they also exhibit exceptional electrocatalytic properties in alkaline seawater (1.833 V@500 mA cm-2 ). The experimental studies and theoretical calculations verify that Fe doping does reduce the energy barrier from OH* to O* intermediates during OER process after catalyst reconstruction, and the non-metallic N site from MoN exhibits the lowest theoretical overpotential. The splendid catalytic performance is attributed to the optimized local electron configuration and porous structure. This discovery provides a new design method toward low-cost and excellent catalysts for water/seawater splitting to produce hydrogen.

Unraveling the Structure-Activity-Stability Relationship over Gallium-Promoted HZSM-5 Nanocrystalline Aggregates for Propane Aromatization.

The aromatization of light alkane is an important process for increasing the aromatic production and utilization efficiency of light alkane resources simultaneously. Herein, Ga-modified HZSM-5 catalysts were prepared and investigated by a series of characterization techniques such as X-ray diffraction, nuclear magnetic resonance spectroscopy, transmission electron microscopy, N2 adsorption-desorption, and NH3 temperature-programmed desorption to study their physicochemical properties. The catalytic performance in propane aromatization was also tested. Importantly, the structure-activity relationship, reaction pathway, and coke formation mechanism in propane aromatization were systematically explored. It was found that different Ga introduction methods would affect the amounts of Brønsted and Lewis acid sites, and Ga-HZSM-5 prepared by the hydrothermal method exhibited higher amounts of Brønsted and Lewis acid sites but a lower B/L ratio. As a result, Ga-HZSM-5 showed higher propane conversion and benzene, toluene, and xylene yield compared with that of Ga2O3/HZSM-5. The propane aromatization reaction pathway indicated that propane dehydrogenation to propene was a crucial step for aromatic formation. The increase of the Lewis acid density in Ga-HZSM-5 can effectively improve the dehydrogenation rate and promote the aromatization reaction. Furthermore, the formation of coke species was studied by thermogravimetry-mass spectrometry and Raman approaches, the results of which indicated that the graphitization degree of coke formed over spent Ga-HZSM-5 is lower, resulting in enhanced anticoking stability.

Improving domain generalization performance for medical image segmentation via random feature augmentation.

Deep convolutional neural networks (DCNNs) have shown remarkable performance in medical image segmentation tasks. However, medical images frequently exhibit distribution discrepancies due to variations in scanner vendors, operators, and image quality, which pose significant challenges to the robustness of trained models when applied to unseen clinical data. To address this issue, domain generalization methods have been developed to enhance the generalization ability of DCNNs. Feature space-based data augmentation methods have been proven effective in improving domain generalization, but they often rely on prior knowledge or assumptions, which can limit the diversity of source domain data. In this study, we propose a novel random feature augmentation (RFA) method to diversify source domain data at the feature level without prior knowledge. Specifically, our RFA method perturbs domain-specific information while preserving domain-invariant information, thereby adequately diversifying the source domain data. Furthermore, we propose a dual-branches invariant synergistic learning strategy to capture domain-invariant information from the augmented features of RFA, enabling DCNNs to learn a more generalized representation. We evaluate our proposed method on two challenging medical image segmentation tasks, optic cup/disc segmentation on fundus images and prostate segmentation on MRI images. Extensive experimental results demonstrate the superior performance of our method over state-of-the-art domain generalization methods.

Synergetic Regulation of the Microstructure and Acidity of HZSM-5/MCM-41 for Efficient Catalytic Cracking of n-Decane.

Alkane catalytic cracking is regarded as one of the most significant processes for light olefin production; however, it suffers from serve catalyst deactivation due to coke formation. Herein, HZSM-5/MCM-41 composites with different Si/Al2 ratios were first prepared by the hydrothermal method. The physicochemical properties of the prepared catalysts were analyzed by a series of bulk and surface characterization methods, and the catalytic performance was tested in n-decane catalytic cracking. It was found that HZSM-5/MCM-41 showed a higher selectivity to light olefins and a lower deactivation rate compared with the parent HZSM-5 due to an enhanced diffusion rate and decreased acid density. Moreover, the structure-reactivity relationship revealed that conversion, light olefin selectivity, and the deactivation rate strongly depended on the total acid density. Furthermore, HZSM-5/MCM-41 was further extruded with γ-Al2O3 to obtain the catalyst pellet, which showed an even higher selectivity to light olefins (∼48%) resulting from the synergy effect of the fast diffusion rate and passivation of external acid density.

Integrating Amorphous Molybdenum Sulfide Nanosheets with a Co9S8@Ni3S2 Array as an Efficient Electrocatalyst for Overall Water Splitting.

It is highly challenging to design low-cost, efficient electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, a hierarchical heterostructure was constructed on three-dimensional (3D) Ni foam, which contains Ni3S2 nanorods decorated with both Co9S8 and amorphous MoSx nanosheets and Ni3S2 nanowires decorated with amorphous MoSx nanosheets, namely, MoSx@Co9S8@Ni3S2/NF. The synergistic effects from the strong interactions of the heterointerface and unique hierarchical heterostructure endow the MoSx@Co9S8@Ni3S2/NF with abundant active sites and effective mass and electron transport pathways, resulting in excellent activity toward both HER and OER in 1 M KOH. It only gives a low overpotential of 76.5 mV to achieve 10 mA cm-2 for HER and a low overpotential of 310 mV to achieve 100 mA cm-2 for OER. Based on the superior catalytic activity of MoSx@Co9S8@Ni3S2/NF for OER and HER, we demonstrated the activity of overall water splitting using MoSx@Co9S8@Ni3S2/NF as both the anode and cathode. It shows a higher catalytic activity for overall water splitting with a low cell voltage of 1.52 V at 10 mA cm-2 than commercial Pt/C/NF||IrO2/NF (1.61 V) and superior stability. This work provides a platform for the design and preparation of efficient electrocatalysts with various hierarchical heterostructures.

Quasi-2D Bilayer Surface Passivation for High Efficiency Narrow Bandgap Perovskite Solar Cells.

The combination of comprehensive surface passivation and effective interface carriers transfer plays a critical role in high-performance perovskite solar cells. A 2D structure is an important approach for surface passivation of perovskite film, however, its large band gap could compromise carrier transfer. Herein, we synthesize a new molecule 2-thiopheneethylamine thiocyanate (TEASCN) for the construction of bilayer quasi-2D structure precisely on a tin-lead mixed perovskite surface. This bilayer structure can passivate the perovskite surface and ensure effective carriers transfer simultaneously. As a result, the open-circuit voltage (Voc ) of the device is increased without sacrificing short-circuit current density (Jsc ), giving rise to a high certified efficiency from a credible third-party certification of narrow band gap perovskite solar cells. Furthermore, theoretical simulation indicates that the inclusion of TEASCN makes the bilayer structure thermodynamically more stable, which provides a strategy to tailor the number of layers of quasi-2D perovskite structures.

One-Step Synthesis of SnI2·(DMSO)x Adducts for High-Performance Tin Perovskite Solar Cells.

Contemporary thin-film photovoltaic (PV) materials contain elements that are scarce (CIGS) or regulated (CdTe and lead-based perovskites), a fact that may limit the widespread impact of these emerging PV technologies. Tin halide perovskites utilize materials less stringently regulated than the lead (Pb) employed in mainstream perovskite solar cells; however, even today's best tin-halide perovskite thin films suffer from limited carrier diffusion length and poor film morphology. We devised a synthetic route to enable in situ reaction between metallic Sn and I2 in dimethyl sulfoxide (DMSO), a reaction that generates a highly coordinated SnI2·(DMSO)x adduct that is well-dispersed in the precursor solution. The adduct directs out-of-plane crystal orientation and achieves a more homogeneous structure in polycrystalline perovskite thin films. This approach improves the electron diffusion length of tin-halide perovskite to 290 ± 20 nm compared to 210 ± 20 nm in reference films. We fabricate tin-halide perovskite solar cells with a power conversion efficiency of 14.6% as certified in an independent lab. This represents a ∼20% increase compared to the previous best-performing certified tin-halide perovskite solar cells. The cells outperform prior earth-abundant and heavy-metal-free inorganic-active-layer-based thin-film solar cells such as those based on amorphous silicon, Cu2ZnSn(S/Se)4 , and Sb2(S/Se)3.

Low-Dimensional Inorganic Tin Perovskite Solar Cells Prepared by Templated Growth.

The manipulation of the dimensionality and nanostructures based on the precise control of the crystal growth kinetics boosts the flourishing development of perovskite optoelectronic materials and devices. Herein, a low-dimensional inorganic tin halide perovskite, CsSnBrI2-x (SCN)x , with a mixed 2D and 3D structure is fabricated. A kinetic study indicates that Sn(SCN)2 and phenylethylamine hydroiodate can form a 2D perovskite structure that acts as a template for the growth of the 3D perovskite CsSnBrI2-x (SCN)x . The film shows an out-of-plane orientation and a large grain size, giving rise to reduced defect density, superior thermostability, and oxidation resistance. A solar cell based on this low-dimensional film reaches a power conversion efficiency of 5.01 %, which is the highest value for CsSnBrx I3-x perovskite solar cells. Furthermore, the device shows enhanced stability in ambient air.

A deep learning-based framework for lung cancer survival analysis with biomarker interpretation.

BACKGROUND: Lung cancer is the leading cause of cancer-related deaths in both men and women in the United States, and it has a much lower five-year survival rate than many other cancers. Accurate survival analysis is urgently needed for better disease diagnosis and treatment management. RESULTS: In this work, we propose a survival analysis system that takes advantage of recently emerging deep learning techniques. The proposed system consists of three major components. 1) The first component is an end-to-end cellular feature learning module using a deep neural network with global average pooling. The learned cellular representations encode high-level biologically relevant information without requiring individual cell segmentation, which is aggregated into patient-level feature vectors by using a locality-constrained linear coding (LLC)-based bag of words (BoW) encoding algorithm. 2) The second component is a Cox proportional hazards model with an elastic net penalty for robust feature selection and survival analysis. 3) The third commponent is a biomarker interpretation module that can help localize the image regions that contribute to the survival model's decision. Extensive experiments show that the proposed survival model has excellent predictive power for a public (i.e., The Cancer Genome Atlas) lung cancer dataset in terms of two commonly used metrics: log-rank test (p-value) of the Kaplan-Meier estimate and concordance index (c-index). CONCLUSIONS: In this work, we have proposed a segmentation-free survival analysis system that takes advantage of the recently emerging deep learning framework and well-studied survival analysis methods such as the Cox proportional hazards model. In addition, we provide an approach to visualize the discovered biomarkers, which can serve as concrete evidence supporting the survival model's decision.

Exploration of the Effect of Blue Light on Functional Metabolite Accumulation in Longan Embryonic Calli via RNA Sequencing.

Light is an important factor that affects the synthesis of functional metabolites in longan embryogenic calli (ECs). However, analysis of the effect of light on functional metabolites in longan ECs via RNA sequencing has rarely been reported and their light regulation network is unclear. The contents of various functional metabolites as well as the enzymatic activities of superoxide dismutase and peroxidase and the level of H2O2 in longan ECs were significantly higher under blue light treatment than under the other treatments (dark, white). In this study, we sequenced three mRNA libraries constructed from longan ECs subjected to different treatments. A total of 4463, 1639 and 1806 genes were differentially expressed in the dark versus blue (DB), dark versus white (DW) and white versus blue (WB) combinations, respectively. According to GO and KEGG analyses, most of the differentially expressed genes (DEGs) identified were involved in transmembrane transport, taurine and hypotaurine metabolism, calcium transport and so forth. Mapman analysis revealed that more DEGs were identified in each DB combination pathway than in DW combination pathways, indicating that blue light exerts a significantly stronger regulatory effect on longan EC metabolism than the other treatments. Based on previous research and transcriptome data mining, a blue light signaling network of genes that affect longan functional metabolites was constructed and HY5, PIF4 and MYC2 were shown to be the key regulatory genes in the network. The results of this study demonstrate that the expression levels of phase-specific genes vary with changes in longan EC functional metabolites.

Exploration of the effect of blue light on microRNAs involved in the accumulation of functional metabolites of longan embryonic calli through RNA-sequencing.

BACKGROUND: The regulation of functional metabolites under light by structural genes and regulatory genes is understood but the roles of microRNAs in this pathway have rarely been reported and their regulation network is not yet clear. RESULTS: Blue light was most conducive to promoting the synthesis of some functional metabolites in longan embryonic callus (ECs). In this study, we sequenced three small RNA libraries of constructed longan ECs under different light qualities (dark, blue, and white). A total of 29 and 22 miRNAs were differentially expressed in the dark versus blue (DB) and dark versus white (DW) combinations, respectively. According to Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, most of the differentially expressed miRNA target genes were involved in plant hormone signal transduction, mitogen-activated protein kinase (MAPK) signaling, biosynthesis of unsaturated fatty acids, and so on. Cytoscape analysis of the target genes of miRNAs indicated that miR396b-5p and miR5139 had the most target genes in DB. Moreover, this study also found that miR171f_3 targeted DELLA, miR390e targeted BRI1, miR396b-5p targeted EBF1/2 and EIN3; these miRNAs participated in the blue light signaling network through their target genes and regulated the accumulation of longan functional metabolites. CONCLUSIONS: The results of the study revealed that the expressions of phase-specific miRNAs vary with the change of functional metabolites in longan ECs. This study provides new insights into the molecular mechanisms that allow light to influence plant metabolism. © 2018 Society of Chemical Industry.

Enhanced Adsorptivity of Hexavalent Chromium in Aqueous Solutions Using CTS@nZVI Modified Wheat Straw-Derived Porous Carbon.

Using KOH-modified wheat straw as the precursor, wheat straw biochar was produced through carbonization at 500 °C. Subsequently, a synthetic material containing nano-zero-valent iron (nZVI) was prepared via liquid phase reduction (nZVI-WSPC). To enhance its properties, chitosan (CTS) was used by crosslinking to form the new adsorbent named CTS@nZVI-WSPC. The impact of CTS on parameters such as mass ratio, initial pH value, and adsorbent dosage on the adsorption efficiency of Cr(VI) in solution was investigated through one-factor experiments. Isotherm adsorption and thermodynamic analysis demonstrated that the adsorption of Cr(VI) by CTS@nZVI-WSPC conforms to the Langmuir model, with a maximum adsorption capacity of 147.93 mg/g, and the adsorption process is endothermic. Kinetic analysis revealed that the adsorption process follows a pseudo-second-order kinetic model. The adsorption mechanism, as elucidated by SEM, FTIR, XPS, and XRD, suggests that the process may involve multiple mechanisms, including pore adsorption, electrostatic adsorption, chemical reduction, and surface chelation. The adsorption capacity of Cr(VI) by CTS@nZVI-WSPC remains high after five cycles. The adsorbent is simple to operate, economical, efficient, and reusable, making it a promising candidate for the treatment of Cr(VI) in water.

Unraveling the Mechanisms of Cannabidiol's Pharmacological Actions: A Comprehensive Research Overview.

Cannabis sativa has long been used for neurological and psychological healing. Recently, cannabidiol (CBD) extracted from cannabis sativa has gained prominence in the medical field due to its non-psychotropic therapeutic effects on the central and peripheral nervous systems. CBD, also acting as a potent antioxidant, displays diverse clinical properties such as anticancer, antiinflammatory, antidepressant, antioxidant, antiemetic, anxiolytic, antiepileptic, and antipsychotic effects. In this review, we summarized the structural activity relationship of CBD with different receptors by both experimental and computational techniques and investigated the mechanism of interaction between related receptors and CBD. The discovery of structural activity relationship between CBD and target receptors would provide a direction to optimize the scaffold of CBD and its derivatives, which would give potential medical applications on CBD-based therapies in various illnesses.

Physical Activity and Weight Loss Among Adults With Type 2 Diabetes and Overweight or Obesity: A Post Hoc Analysis of the Look AHEAD Trial.

Importance: Prior findings from the Look AHEAD trial showed no significant reduction in the risk of cardiovascular events by lifestyle-induced weight loss among individuals with type 2 diabetes (T2D) and overweight or obesity. However, physical activity (PA) may modify the changes in cardiovascular risk associated with weight loss. Objective: To examine the joint association of weight loss and PA with the risk of adverse cardiovascular events in patients with T2D and overweight or obesity. Design, Setting, and Participants: This cohort study was a post hoc analysis of the Look AHEAD randomized clinical trial, which compared the cardiovascular effects of weight loss by intensive lifestyle intervention vs diabetes support and education among individuals with T2D and overweight or obesity. The study was conducted from June 2001 to September 2012, and participants were patients in the substudy of accelerometry-measured PA from 8 locations in the United States. Data were analyzed from June to August 2023. Exposures: Body weight change and accelerometer-derived PA volume across the first 4 years. Main Outcomes and Measures: The primary outcome was a composite cardiovascular outcome including cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for angina. Results: Among a total of 1229 participants (mean [SD] age, 60 [7] years; 533 male [43%]), 333 (27%) achieved and maintained weight loss for the first 4 years. Among the individuals who maintained weight loss, 105 (32%) maintained high PA volume. During a median of 9.5 years of follow-up, 198 participants (16.1%) experienced the primary outcome. Compared with those with low PA volume and no weight loss (105 [15.8%]), maintaining high PA volume and weight loss was associated with a 61% lower risk of the primary end point (hazard ratio, 0.39; 95% CI, 0.19-0.81; P = .01). However, there was no significant difference in the risk of the primary end point among those with either weight loss only or high PA only. The multiplicative interaction between weight loss and PA for the risk of cardiovascular events was also significant (P for interaction = .01). Conclusions and Relevance: In this cohort study, maintaining weight loss and higher PA volume was associated with a lower risk of the composite cardiovascular outcome. The findings suggest that the cardiovascular benefits of PA may vary and be enhanced by weight loss among individuals with T2D and overweight or obesity.

Surface heterojunction based on n-type low-dimensional perovskite film for highly efficient perovskite tandem solar cells.

Enhancing the quality of junctions is crucial for optimizing carrier extraction and suppressing recombination in semiconductor devices. In recent years, metal halide perovskite has emerged as the most promising next-generation material for optoelectronic devices. However, the construction of high-quality perovskite junctions, as well as characterization and understanding of their carrier polarity and density, remains a challenge. In this study, using combined electrical and spectroscopic characterization techniques, we investigate the doping characteristics of perovskite films by remote molecules, which is corroborated by our theoretical simulations indicating Schottky defects consisting of double ions as effective charge dopants. Through a post-treatment process involving a combination of biammonium and monoammonium molecules, we create a surface layer of n-type low-dimensional perovskite. This surface layer forms a heterojunction with the underlying 3D perovskite film, resulting in a favorable doping profile that enhances carrier extraction. The fabricated device exhibits an outstanding open-circuit voltage (VOC) up to 1.34 V and achieves a certified efficiency of 19.31% for single-junction wide-bandgap (1.77 eV) perovskite solar cells, together with significantly enhanced operational stability, thanks to the improved separation of carriers. Furthermore, we demonstrate the potential of this wide-bandgap device by achieving a certified efficiency of 27.04% and a VOC of 2.12 V in a perovskite/perovskite tandem solar cell configuration.

Exploration of the effect of blue laser light on microRNAs involved in functional metabolism in D. officinale through RNA sequencing.

Dendrobium officinale has remarkable medicinal functions and high economic value. Laser light sources are different from ordinary light sources in terms of the light emission mechanism and play important roles regulating functional metabolite synthesis in D. officinale. However, the mechanism by which miRNAs participate in regulating the D. officinale response to blue laser irradiation has not been reported. Previous studies found that the number of red leaves on plants treated with blue laser light was greater than that on plants treated with blue light and white light, and blue laser light was most effective at promoting the accumulation of total flavonoids, polysaccharides and alkaloids. RNA-seq was used to analyse the difference in the effects of lasers on D. officinale. KEGG analysis of the target genes of differentially expressed (DE) miRNAs showed that there were multiple blue laser response pathways, among which peroxisome, nitrogen metabolism, terpenoid biosynthesis, porphyrin and chlorophyll metabolism played central roles. Cytoscape interaction analysis of DE miRNA targets showed that novel_miR_248 most likely participates in the influence of blue laser irradiation on D. officinale. Content verification in D. officinale showed that blue laser light could also increase the total terpene, chlorophyll levels, nitrate reductase, glutamine synthase and glutamate dehydrogenase. Combined with the qPCR results, these findings showed that miR395b, miR827 and miR319l may participate in the blue laser signalling network through their target genes and then regulate the accumulation of functional metabolites in D. officinale. This study provides a scientific basis for the high-yield production of D. officinale.

RNA sequencing-based exploration of the effects of far-red light on microRNAs involved in the shade-avoidance response of D. officinale.

Dendrobium officinale (D. officinale) has remarkable medicinal functions and high economic value. The shade-avoidance response to far-red light importantly affects the D. officinale productivity. However, the regulatory mechanism of miRNAs involved in the far-red light-avoidance response is unknown. Previous studies have found that, in D. officinale, 730 nm (far-red) light can promote the accumulation of plant metabolites, increase leaf area, and accelerate stem elongation. Here, the effects of far-red light on D. officinale were analysed via RNA-seq. KEGG analysis of miRNA target genes revealed various far-red light response pathways, among which the following played central roles: the one-carbon pool by folate; ascorbate and aldarate; cutin, suberine and wax biosynthesis; and sulfur metabolism. Cytoscape analysis of DE miRNA targets showed that novel_miR_484 and novel_miR_36 were most likely involved in the effects of far-red light on the D. officinale shade avoidance. Content verification revealed that far-red light promotes the accumulation of one-carbon compounds and ascorbic acid. Combined with qPCR validation results, the results showed that miR395b, novel_miR_36, novel_miR_159, novel_miR_178, novel_miR_405, and novel_miR_435 may participate in the far-red light signalling network through target genes, regulating the D. officinale shade avoidance. These findings provide new ideas for the efficient production of D. officinale.

Magnetically-separable acid-resistant CoFe2O4@Polymer@MIL-100 core-shell catalysts for the acetalization of benzaldehyde and methanol.

Novel reusable acid-resistant magnetic polymer nanospheres-immobilized MIL-100 (CoFe2O4@Polymer@MIL-100) catalyst was prepared by a layer-by-layer method to achieve a controllable structure. The obtained core-shell catalyst consisted of modified magnetic nanoparticles as the core, a carboxylic-functionalized polymer as the protective layer, and an MIL-100 shell as the active catalytic layer by chemical bonds on the polymer. The catalysts showed good stability, good magnetic saturation, and acid corrosion resistance. The thickness of the MIL-100 shell could be adjusted by controlling the metal salt concentration and the number of layer-by-layer cycles. Nano-sized MIL-100 showed better mass transfer efficiency and catalytic activity. A conversion of 97.7% after 10 min was observed during acetalization when using CoFe2O4@Polymer@MIL-100 as the catalyst. CoFe2O4@Polymer@MIL-100 could be reused at least five times. The use of a polymer layer on CoFe2O4@Polymer@MIL-100 prevented acidic ligands from corroding the magnetic core. Chemical bonds between MIL-100 and functional magnetic polymer cores improved the catalyst's stability. CoFe2O4@Polymer@MIL-100 exhibited high activity, excellent stability, and easy magnetic separation.

Improved Structural Order and Exciton Delocalization in High-Member Quasi-Two-Dimensional Tin Halide Perovskite Revealed by Electroabsorption Spectroscopy.

Engineering of quasi-two-dimensional (quasi-2D) tin halide perovskite structures is a promising pathway to achieve high-performance lead-free perovskite solar cells, with recently developed devices demonstrating over 14% efficiency. Despite the significant efficiency improvement over the bulk three-dimensional (3D) tin perovskite solar cells, the precise relationship between structural engineering and electron-hole (exciton) properties is not fully understood. Here, we study exciton properties in high-member quasi-2D tin perovskite (which is dominated by large n phases) and bulk 3D tin perovskite using electroabsorption (EA) spectroscopy. By numerically extracting the changes in polarizability and dipole moment between the excited and ground states, we show that more ordered and delocalized excitons are formed in the high-member quasi-2D film. This result indicates that the high-member quasi-2D tin perovskite film consists of more ordered crystal orientations and reduced defect density, which is in agreement with the over 5-fold increase in exciton lifetime and much improved solar cell efficiency in devices. Our results provide insights on the structure-property relationship of high-performance quasi-2D tin perovskite optoelectronic devices.

Surface-Energy-Regulated Growth of α-Phase Cs0.03 FA0.97 PbI3 for Highly Efficient and Stable Inverted Perovskite Solar Cells.

Methylammonium (MA)-free formamidinium (FA)-dominated Csx FA1-x PbI3 is rising as the most promising candidate for highly efficient and stable perovskite solar cells. However, the growth of high-quality Csx FA1-x PbI3 black-phase perovskite structure without ion doping in the lattice remains a challenge. Herein, propeller-shaped halogenated tertiary ammonium is synthesized, showing high binding energy on the perovskite surface and large steric hindrance. This molecule can significantly reduce the barrier of high surface energy that suppresses the growth of the α-phase Csx FA1-x PbI3 structure. As a result, the α-phase structure can be formed at room temperature, which can further act as a seed for the growth of high-quality film. Solar cells based on the film show a record efficiency up to 23.6% for MA free Csx FA1- x PbI3 solar cells with inverted structure and excellent stability at 85 °C over 200 h.