Tungstate-mediated In-situ Passivation of Grain Boundary Grooves in Perovskite Solar Cells.

Possessed with advantageous optoelectronic properties, perovskites have boosted the rapid development of solution-processed solar cells. The performance of perovskite solar cells (PSCs) is significantly weakened by the carrier loss at grain boundary grooves (GBGs); however, it receives limited attention and there lacks effective approach to solve this issue. Herein, for the first time, we constructed the tungstate/perovskite heterointerface via a "two step" in situ reaction approach that provides effective defect passivation and ensures efficient carrier dynamics at the GBGs. The exposed perovskite at grain boundaries is converted to wide-band-gap PbWO4 via an in-situ reaction between Pb2+ and tungstate ions, which passivate defects due to the strong ionic bonding. Moreover, recombination loss is further suppressed via the heterointerface energetics modification based on an additional transformation from PbWO4 to CaWO4 . PSCs based on this groove modification strategy showed good universality in both normal and inverted structure, with an improved efficiency of 23.25 % in the n-i-p device and 23.33 % in the p-i-n device. Stable power output of the modified device could maintain 91.7 % after around 1100 h, and the device efficiency could retain 92.5 % after aging in air for around 2110 h, and 93.1 % after aging at 85 °C in N2 for 972 h.

Avoiding Structural Collapse to Reduce Lead Leakage in Perovskite Photovoltaics.

Perovskite solar cells (PSCs) have become a promising candidate for the next-generation photovoltaic technologies. As an essential element for high-efficiency PSCs however, the heavy metal Pb is soluble in water, causing a serious threat to the environment and human health. Due to the weak ionic bonding in three-dimensional (3D) perovskites, drastic structure decomposition occurs when immersing the perovskite film in water, which accelerates the Pb leakage. By introducing the chemically stable Dion-Jacobson (DJ) 2D perovskite at the 3D perovskite surface, the film dissolution is significantly slowed down, which retards lead leakage. As a result, the Pb contamination is dramatically reduced under various extreme conditions. In addition, the PSCs device deliver a power conversion efficiency (PCE) of 23.6 % and retain over 95 % of their initial PCE after the maximum power point tracking for over 1100 h.

Symmetry-Reduction Enhanced Polarization-Sensitive Photodetection in Core-Shell SbI3 /Sb2 O3 van der Waals Heterostructure.

Structural symmetry is a simple way to quantify the anisotropic properties of materials toward unique device applications including anisotropic transportation and polarization-sensitive photodetection. The enhancement of anisotropy can be achieved by artificial symmetry-reduction design. A core-shell SbI3 /Sb2 O3 nanowire, a heterostructure bonded by van der Waals forces, is introduced as an example of enhancing the performance of polarization-sensitive photodetectors via symmetry reduction. The structural, vibrational, and optical anisotropies of such core-shell nanostructures are systematically investigated. It is found that the anisotropic absorbance of a core-shell nanowire is obviously higher than that of two single compounds from both theoretical and experimental investigations. Anisotropic photocurrents of the polarization-sensitive photodetectors based on these core-shell SbI3 /Sb2 O3 van der Waals nanowires are measured ranging from ultraviolet (UV) to visible light (360-532 nm). Compared with other van der Waals 1D materials, low anisotropy ratio (Imax /Imin ) is measured based on SbI3 but a device based on this core-shell nanowire possesses a relatively high anisotropy ratio of ≈3.14 under 450 nm polarized light. This work shows that the low-symmetrical core-shell van der Waals heterostructure has large potential to be applied in wide range polarization-sensitive photodetectors.

Wolbachia infection status and molecular diversity in the species of tribe Tagiadini Mabille, 1878 (Lepidoptera: Hesperiidae) collected in China.

Wolbachia, one of the most ubiquitous heritable symbionts in lepidopteran insects, can cause mitochondrial introgression in related host species. We recently found mito-nuclear discordance in the Lepidopteran tribe Tagiadini Mabille 1878 from which Wolbachia has not been reported. In this study, we found that 13 of the 46 species of Tagiadini species tested were positive for Wolbachia. Overall, 14% (15/110) of Tagiadini specimens were infected with Wolbachia and nine new STs were found from 15 isolates. A co-phylogenetic comparison, divergence time estimation and Wolbachia recombination analysis revealed that mito-nuclear discordance in Tagiadini species is not mediated by Wolbachia, but Wolbachia acquisition in Tagiadini appears to have occurred mainly through horizontal transmission rather than codivergence.

Supra-Photothermal CO2 Methanation over Greenhouse-Like Plasmonic Superstructures of Ultrasmall Cobalt Nanoparticles.

Improving the solar-to-thermal energy conversion efficiency of photothermal nanomaterials at no expense of other physicochemical properties, e.g., the catalytic reactivity of metal nanoparticles, is highly desired for diverse applications but remains a big challenge. Herein, a synergistic strategy is developed for enhanced photothermal conversion by a greenhouse-like plasmonic superstructure of 4 nm cobalt nanoparticles while maintaining their intrinsic catalytic reactivity. The silica shell plays a key role in retaining the plasmonic superstructures for efficient use of the full solar spectrum, and reducing the heat loss of cobalt nanoparticles via the nano-greenhouse effect. The optimized plasmonic superstructure catalyst exhibits supra-photothermal CO2 methanation performance with a record-high rate of 2.3 mol gCo -1 h-1 , close to 100% CH4 selectivity, and desirable catalytic stability. This work reveals the great potential of nanoscale greenhouse effect in enhancing photothermal conversions through the combination with conventional promoting strategies, shedding light on the design of efficient photothermal nanomaterials for demanding applications.

Gelation of Hole Transport Layer to Improve the Stability of Perovskite Solar Cells.

To achieve high power conversion efficiency (PCE) and long-term stability of perovskite solar cells (PSCs), a hole transport layer (HTL) with persistently high conductivity, good moisture/oxygen barrier ability, and adequate passivation capability is important. To achieve enough conductivity and effective hole extraction, spiro-OMeTAD, one of the most frequently used HTL in optoelectronic devices, often needs chemical doping with a lithium compound (LiTFSI). However, the lithium salt dopant induces crystallization and has a negative impact on the performance and lifetime of the device due to its hygroscopic nature. Here, we provide an easy method for creating a gel by mixing a natural small molecule additive (thioctic acid, TA) with spiro-OMeTAD. We discover that gelation effectively improves the compactness of resultant HTL and prevents moisture and oxygen infiltration. Moreover, the gelation of HTL improves not only the conductivity of spiro-OMeTAD, but also the operational robustness of the devices in the atmospheric environment. In addition, TA passivates the perovskite defects and facilitates the charge transfer from the perovskite layer to HTL. As a consequence, the optimized PSCs based on the gelated HTL exhibit an improved PCE (22.52%) with excellent device stability.

Inhibited Crack Development by Compressive Strain in Perovskite Solar Cells with Improved Mechanical Stability.

Metal halide perovskites are promising as next-generation photovoltaic materials, but stability issues are still a huge obstacle to their commercialization. Here, the formation and evolution of cracks in perovskite films during thermal cycling, which affect their mechanical stability, are investigated. Compressive strain is employed to suppress cracks and delamination by in situ formed polymers with low elastic modulus during crystal growth. The resultant devices pass the thermal-cycling qualification (IEC61215:2016), retaining 95% of the initial power conversion efficiency (PCE) and compressive strain after 230 cycles. Meanwhile, the p-i-n devices deliver PCEs of 23.91% (0.0805 cm2 ) and 23.27% (1 cm2 ). The findings shed light on strain engineering with respect to their evolution, which enables mechanically stable perovskite solar cells.

Engineering Amorphous-Crystallized Interface of ZrNx Barriers for Stable Inverted Perovskite Solar Cells.

It is challenging to achieve long-term stability of perovskite solar cells due to the corrosion and diffusion of metal electrodes. Integration of compact barriers into devices has been recognized as an effective strategy to protect the perovskite absorber and electrode. However, the difficulty is to construct a thin layer of a few nanometers that can delay ion migration and impede chemical reactions simultaneously, in which the delicate microstructure design of a stable material plays an important role. Herein, ZrNx barrier films with high amorphization are introduced in p-i-n perovskite solar cells. To quantify the amorphous-crystalline (a-c) density, pattern recognition techniques are employed. It is found the decreasing a-c interface in an amorphous film leads to dense atom arrangement and uniform distribution of chemical potential, which retards the interdiffusion at the interface between ions and metal atoms and protect the electrodes from corrosion. The resultant solar cells exhibit improved operational stability, which retains 88% of initial efficiency after continuous maximum power point tracking under 1-Sun illumination at room temperature (25 °C) for 1500 h.

Molecular weight driving bioavailability and intrinsic degradation mechanisms of dissolved organic phosphorus in lake sediment.

The sediment dissolved organic phosphorus (DOP) for the "internal phosphorus (P) loading" has raised intensive concern, but its bioavailability and intrinsic degradation mechanism have not been fully elucidated. In this work, multi-techniques were combined to construct the response of sediments DOP's bioavailability to molecular weight (MW) based on ten lakes of China, thereby elucidating the intrinsic degradation mechanism of sediment DOP. A high percentage (74.5% on average) and significantly positive correlations with respect to different MWs were observed, highlighting the importance of DOP to dissolved P in sediments. DOP is mainly composed of a low MW (LMW) portion (63.8%) and the substances are primarily derived from microbial sources. Bioavailable DOP species were closely related to MW, with labile monoester P and diester P decreased with decreasing MW. Analysis of environmental processes showed that microbial utilization capacity and the characteristics of dissolved organic matter (DOM) with different MWs were the dominant drivers in determining the bioavailability of DOP. That is, microorganisms exhibit high DOM utilization capacity in LMW portion, promoting the degradation and transformation of bioavailable DOP species. Furthermore, the increased humic and fulvic-like substances by microbial degradation might in turn inhibit the enzymatic hydrolysis of LMW-DOP. This pattern explains why the contents of LMW-DOP are very high, but it contains less bioavailable DOP. By studying the bioavailability of sediment DOPs with different MWs, it is found that, under natural conditions, labile monoester and diester P in LMW-DOP have a high tendency to degrade than those in HMW-DOP. The results further show that, microbial utilization and DOM characteristics, as well as their linkage with DOP's bioavailability and degradability, have important implications for assessing DOP's degradation potential. The insights from this study might shed light on more effective strategies for mitigating the risks of "internal P loading".

Photothermal Catalytic CO2 Hydrogenation with High Activity and Tailored Selectivity Over Monodispersed Pd-Ni Nanoalloys.

Bimetallic nanomaterials exhibit excellent catalytic performance in photothermal CO2 hydrogenation due to the synergistic effect between the two metal components. However, the component-performance relationship remains unclear, which hinders the design of efficient bimetallic catalysts and the investigation of catalytic reaction mechanism. Here we illustrate the influence of the composition of binary alloy on their performance of photothermal catalytic CO2 hydrogenation by using monodispersed Pd-Ni nanocrystal as an example. Our study reveals that Ni and Pd play a significantly different role in the catalytic processes. Higher Ni component in the catalysts could lead to stronger light absorption, higher activity, and lower CO selectivity. The optimized Pd4 Ni1 -SiO2 catalyst exhibited a near-unity and stable CO production rate of 230 mmol ⋅ g-1 ⋅ h-1 under 25-sun illumination. This study paves the way for the usage of bimetal in photothermal CO2 catalysis towards more efficient solar-to-chemical energy conversions, and sheds light on some general design principles of bimetallic catalysts to balance the intrinsic properties of individual components.

Stabilization of Exposed Metal Nanocrystals in High-Temperature Heterogeneous Catalysis.

Colloidal metal nanocrystals with uniform sizes, shapes, compositions, and architectures are ideal building blocks for constructing heterogeneous catalysts with well-defined characteristics toward the investigation of accurate structure-property relationships and better understanding of catalytic mechanism. However, their applications in high-temperature heterogeneous catalysis are often restricted by the difficulty in maintaining the high metal dispersity and easy accessibility to active sites under harsh operating conditions. Here, a partial-oxide-coating strategy is proposed to stabilize metal nanocrystals against sintering and meanwhile enable an effective exposure of active sites. As a proof-of-concept, controlled partial silica coating of colloidally prepared Pd0.82 Ni0.18 nanocrystals with the size of 8 nm is demonstrated. This partially coated catalyst exhibits excellent activity, selectivity, and stability, outperforming its counterparts with fully coated and supported structures, in reverse water gas shift (RWGS) catalysis particularly at high operating temperatures. This study opens a new avenue for the exploration of colloidal metal nanocrystals in high-temperature heterogeneous catalysis.

Stable Cu Catalysts Supported by Two-dimensional SiO2 with Strong Metal-Support Interaction.

Cu-based catalysts exhibit excellent performance in hydrogenation reactions. However, the poor stability of Cu catalysts under high temperatures has restricted their practical applications. The preparation of stable Cu catalysts supported by SiO2 with strong metal-support interaction (SMSI) has thus aroused great interest due to the high abundance, low toxicity, feasible processability, and low cost of SiO2 . The challenge in the construction of such SMSI remains to be the inertness of SiO2 . Herein, a simple and scalable method is developed to prepare 2D silica (2DSiO2 ) supported Cu catalysts with SMSI by carefully manipulating the topological exfoliation of CaSi2 with CuCl2 and thereafter calcination. The prepared Cu-2DSiO2 catalysts with the unique encapsulated Cu nanoparticles exhibit excellent activity and long-term stability in high-temperature CO2 hydrogenation reactions. This feasible and low-cost solution for stabilizing Cu catalysts might shed light on their realistic applications.

Young Adults' Loneliness and Depression During the COVID-19 Pandemic: A Moderated Mediation Model.

Since the outbreak of the COVID-19 pandemic in December 2019, millions of people have been infected with the disease. The COVID-19 pandemic also produced severe mental health problems, such as loneliness and depression. The present study aimed to examine the mediating role of cognitive reappraisal and moderating role of resilience in the relationship between young adults' loneliness and depression during the pandemic by adopting a cross-sectional research approach. In March 2020, 654 young adults (18-29 years old) were recruited to complete the measures for loneliness, depression, emotion regulation, and resilience. Results found that loneliness was positively and moderately associated with depression (r = 0.531, p < 0.001), and that both loneliness and depression were separately negatively associated with cognitive reappraisal (r = -0.348, p < 0.001; r = -0.424, p < 0.001) and resilience (r = -0.436, p < 0.001; r = -0.419, p < 0.001). The results indicated that both loneliness and depression were not associated with expressive suppression (r = 0.067, p = 0.087; r = -0.002, p = 0.961). The moderated mediation model results revealed that only cognitive reappraisal partially mediated the relationship between loneliness and depression (b = -0.301; Boot 95% CI = -0.388, -0.215). In addition, the results of the moderated mediation model indicated that resilience moderated the association between loneliness and depression (b = 0.035, p < 0.001, Boot 95% CI = 0.014, 0.055), while also moderated the impact of cognitive reappraisal on depression (b = -0.031, p < 0.001, Boot 95% CI = -0.058, -0.005). These findings have practical implications that broaden our understanding of depression in young adults and shed light on how to enhance cognitive reappraisal and resilience as a means of combating depression in this age group during the COVID-19 pandemic.

Initializing film homogeneity to retard phase segregation for stable perovskite solar cells.

The mixtures of cations and anions used in hybrid halide perovskites for high-performance solar cells often undergo element and phase segregation, which limits device lifetime. We adapted Schelling's model of segregation to study individual cation migration and found that the initial film inhomogeneity accelerates materials degradation. We fabricated perovskite films (FA1-xCsxPbI3; where FA is formamidinium) through the addition of selenophene, which led to homogeneous cation distribution that retarded cation aggregation during materials processing and device operation. The resultant devices achieved enhanced efficiency and retained >91% of their initial efficiency after 3190 hours at the maximum power point under 1 sun illumination. We also observe prolonged operational lifetime in devices with initially homogeneous FACsPb(Br0.13I0.87)3 absorbers.

Relatedness Need Satisfaction and the Dark Triad: The Role of Depression and Prevention Focus.

Dark triad traits are often associated with maladaptive social and interpersonal interactions, such as dishonesty and self-centeredness; thus, it is important to explore predictors of the dark triad in order to better facilitate the reduction of such behaviors. The present study adopted a self-report approach with a total of 5,207 Chinese undergraduate students participated in the study. We found that relatedness need dissatisfaction significantly predicted the presence of dark personalities, which was mediated by prevention focus. Conditional process model analysis found that this mediating effect was stronger when depression levels were lower. Final study results contributed to further understanding predictors of the dark triad. Study limitations and future research directions were also examined.

Ru-Catalyzed Reverse Water Gas Shift Reaction with Near-Unity Selectivity and Superior Stability.

Cascade catalysis of reverse water gas shift (RWGS) and well-established CO hydrogenation holds promise for the conversion of greenhouse gas CO2 and renewable H2 into liquid hydrocarbons and methanol under mild conditions. However, it remains a big challenge to develop low-temperature RWGS catalysts with high activity, selectivity, and stability. Here, we report the design of an efficient RWGS catalyst by encapsulating ruthenium clusters with the size of 1 nm inside hollow silica shells. The spatially confined structure prevents the sintering of Ru clusters while the permeable silica layer allows the diffusion of gaseous reactants and products. This catalyst with reduced particle sizes not only inherits the excellent activity of Ru in CO2 hydrogenation reactions but also exhibits nearly 100% CO selectivity and superior stability at 200-500 °C. The ability to selectively produce CO from CO2 at relatively low temperatures paves the way for the production of value-added fuels from CO2 and renewable H2.

Efficacy and Safety of Expanded Hemodialysis with the Theranova 400 Dialyzer: A Randomized Controlled Trial.

BACKGROUND AND OBJECTIVES: Expanded hemodialysis therapy enabled by medium cut-off membranes may promote greater clearance of larger middle molecules that comprise putative uremic solutes than conventional high-flux dialysis. This randomized trial evaluated the efficacy and safety of hemodialysis treatment with a medium cut-off dialyzer. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Clinically stable patients on maintenance hemodialysis were randomized to receive dialysis with either a medium cut-off dialyzer (Theranova 400) or a high-flux dialyzer (Elisio-17H) over 24 weeks of treatment. The primary safety end point was the predialysis serum albumin level after 24 weeks of treatment. The primary efficacy end point was the reduction ratio of free λ light chains at 24 weeks of treatment. RESULTS: Among 172 patients on maintenance hemodialysis, mean age was 59±13 years, 61% were men, 40% were Black, and mean dialysis vintage was 5±4 years. Of the 86 patients randomized to each dialyzer, 65 completed the trial in each group. The reduction ratio for the removal of free λ light chains was significantly higher in the Theranova 400 group compared with the Elisio-17H group after 4 weeks (39% versus 20%) and 24 weeks (33% versus 17%; both P<0.001). Among secondary end points, the Theranova 400 group demonstrated significantly larger reduction ratios at 4 and 24 weeks for complement factor D, free κ light chains, TNFα, and ß2-microglobulin (P<0.001 for all), but not for IL-6. Predialysis serum albumin levels were similar between groups after 24 weeks (4 g/dl with the Theranova 400 and 4.1 g/dl with the Elisio-17H), consistent with noninferiority of the Theranova 400 dialyzer in maintaining predialysis serum albumin levels after 24 weeks of treatment. CONCLUSIONS: Hemodialysis therapy with the Theranova 400 dialyzer provides superior removal of larger middle molecules, as exemplified by free λ light chains, compared with a similar size high-flux dialyzer, while maintaining serum albumin level. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: A Multi-Center, Prospective, Randomized, Controlled, Open-Label, Parallel Study to Evaluate the Safety and Efficacy of the Theranova 400 Dialyzer in End Stage Renal Disease (ESRD) Patients, NCT03257410.

Protective effect of autophagy on endoplasmic reticulum stress induced apoptosis of alveolar epithelial cells in rat models of COPD.

During the present study, we explored the protective effects of autophagy on endoplasmic reticulum (ER) stress (ERS) induced apoptosis belonging to alveolar epithelial cells (AECs) in rat models with chronic obstructive pulmonary disease (COPD). Fifty-six 12-week-old male Sprague-Dawley (SD) rats were randomly assigned into the COPD group (rats exposed to cigarette smoke (CS)), the 3-methyladenine (3-MA) intervention group (COPD rats were administrated with 10 mg/kg autophagy inhibitors), the chloroquine (CQ)-intervention group (COPD rats were administrated 40 mg/kg CQ), and the control group (rats breathed in normal saline). The forced expiratory volume in 0.3 s/forced vital capacity (FEV0.3/FVC%), inspiratory resistance (RI), and dynamic lung compliance (Cdyn) were measured and recorded. The expressions of PKR-like ER kinase (PERK) and CCAAT/enhancer-binding protein-homologous protein (CHOP) were detected by immunohistochemistry. The cell apoptotic rates of AECs were analyzed by terminal deoxynucleotidyl transferase (TdT) mediated dUTP-biotin nick end-labeling (TUNEL) staining. The expression levels of light chain 3 (LC3-II), p62, Beclin-1, ATG5, ATG7, Caspase-12, and Caspase-3 were detected by Western blotting. Results showed that the COPD group exhibited a lower FEV0.3/FVC% and Cdyn, and a higher RI than the control group. Compared with the control group, the integrated optical density (IOD) values of PERK and CHOP, the apoptotic rate of AECs, and expressions of LC3-II, Beclin-1, ATG5, ATG7, Caspase-3, and Caspase-12 expressions were significantly higher, whereas p62 expression was significantly lower in the COPD group. Based on the results obtained during the present study, it became clear that the inhibition of autophagy could attenuate the ERS-induced apoptosis of AECs in rats with COPD.