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Two-dimensional (2D) organic–inorganic hybrid metal halide perovskites (MHPs) are promising as semiconducting light-emitting materials due to improved environmental stability and unique optical properties, compared with three-dimensional MHPs. However, toxic Pb and relatively low photoluminescence quantum yield (PLQY) limit the potentials of these 2D lead halides in solid-state lighting. Herein, we report a series of F-doped, 2D zinc halide-layered perovskites based on phenylethylamine (PEA), PEA2ZnFxCl4–x, which exhibits efficient white light and the highest PLQY of 21.02% at x = 0.40, seven times higher than that of non-F doping samples for 2D hybrid white-light-emitting MHPs. Steady-state and temperature-dependent optical measurements verify that the white-emission arose from self-trapped excitons and highlight the significant effects of F-doping and defect passivation on efficient photoluminescence. Especially, F-doped 2D zinc halide perovskites show ultrahigh stability with negligible degradation for 1000 h at 80 °C. This work paves an avenue to designing efficient and stable single-component white-light-emitting diodes in solid-state lighting. [ABSTRACT FROM AUTHOR]

The low cost and scalability advantages of printable mesoscopic perovskite solar cells (p‐MPSCs) are impaired by the issue of limited power conversion efficiency (PCE). Herein, the PCE of p‐MPSCs is improved by introducing the polymer additive polyacrylonitrile (PAN) into the formamidinium (FA)‐based perovskite for crystallization and defect modulation. PAN forms hydrogen bond and coordination bond with halide perovskite through its C≡N group. Such interactions improve the crystallization and filling of FA‐based perovskite in the mesoscopic scaffold and bring a long carrier lifetime by passivating defects. The synergy improves the PCE of p‐MPSCs from 16.80% to 18.33%. Meanwhile, the hydrophobic nature of PAN enhances the device's resistance against moisture. This work demonstrates that the polymer additive is a promising choice for breaking the PCE limit of p‐MPSCs. [ABSTRACT FROM AUTHOR]

In the rapid development of perovskite solar cells (PSCs), additive engineering has played a significant role for perovskite crystallization and passivation. The high density of defects at perovskite grain boundaries in the mesoporous scaffold leads to severe nonradiative recombination, which results in severe voltage loss. Herein, a sulfur‐containing Lewis base 2‐(methylthio)ethylamine hydrochloride (MTEACl) is applied in the perovskite precursor solution for printable mesoscopic PSCs with triple‐mesoscopic layer structure. Due to the strong electron donating ability of sulfur, the MTEACl can strongly interact with Pb2+, which can effectively passivate the defects of the perovskite. Correspondingly, the trap density of the perovskite is reduced, contributing to the improvement of power conversion efficiency from 15.18% to 17.17% and open circuit voltage to 995 mV. [ABSTRACT FROM AUTHOR]

Triple‐mesoscopic perovskite solar cells (PSCs) have attracted intensive attention due to the high stability, simple fabrication process, and low material cost. In this structure, the perovskite layer is hosted by a triple‐mesoscopic scaffold of TiO2/ZrO2/carbon, and thus the crystal quality is sensitive to the thermal annealing process. Typically, the annealing process is conducted in a petri dish, for which the solvent evaporation of the perovskite precursor is slowed down, but not controllable and designable. To control the solvent evaporation, annealing chambers are first designed with different shape and vapor releasing channels. Then, physical simulations are performed by a finite element method, and it is found out that the chamber with a crowned top and releasing channels on the bottom sides can realize homogeneous distribution of the solvent vapor. To verify the simulation results, chambers are fabricated by 3D printing technique, for which the printing deviation can be as low as 100 µm. By balancing the solvent evaporation and release, the optimal solvent evaporation is achieved of the perovskite precursor in the triple‐mesoscopic scaffold. This work offers a method to obtain homogeneous distribution of solvent vapor, and provides a new insight into understanding the influence of solvent evaporation during the thermal annealing process for PSCs. [ABSTRACT FROM AUTHOR]

The anion exchange between MAPbX3 (X = I− or Br−) and MAX salts in a solution environment is investigated. We find that I− can enter MAPbBr3 single crystals (SC) in millimeter scale, while Br− can only penetrate the surface of MAPbI3 SC in a micrometer scale. Due to the lattice variation, the reaction is partially reversible. [ABSTRACT FROM AUTHOR]

Printable hole‐conductor‐free perovskite solar cells (PSCs) have attracted intensive research attention due to their high stability and simple manufacturing process. However, the cells have suffered severe potential loss in the absence of the hole transporting layer. The dimensionality of the perovskite absorber in the mesoporous carbon electrodes by conducting post‐treatments is reduced. The low‐dimensional perovskites possess wide‐bandgaps and form type‐II band alignment, favoring directional charge transportation and thus enhancing the device performance. For the cells using MAPbI3 (MA = methylammonium) as the light absorber, the open‐circuit voltage (VOC) is significantly enhanced from 0.92 to 0.98 V after posttreatment, delivering an overall efficiency of 16.24%. For the cells based on FAPbI3 (FA = formamadinium), a high efficiency of 17.47% is achieved with VOC of 1.02 V, which are both the highest reported values for printable hole‐conductor‐free PSCs. This strategy provides a facile method for tuning the energy level alignment for mesoscopic perovskite‐based optoelectronics. [ABSTRACT FROM AUTHOR]

Perovskite solar cells are regarded as the most promising and disruptive photovoltaic of the new generation. Carbon‐based hole‐conductor‐free printable mesoscopic perovskite solar cells (p‐MPSCs) with three mesoscopic layers have garnered considerable interest owing to their simple manufacturing process and cost‐effective raw materials, signaling the potential for commercialization. However, the energy level mismatch between the perovskite and the carbon electrode as well as defects at perovskite grain boundaries inevitably lead to additional non‐radiative carrier recombination and large voltage loss. In this study, a facile in situ reconstruction post‐treatment approach is employed to integrate lead sulfide (PbS) and the two‐dimensional (2D) perovskite K2PbI4 into the mesoporous scaffolds of p‐MPSCs. In this way, grain boundary defects are effectively passivated and the ion migration is suppressed by introducing 2D perovskite K2PbI4 at grain boundaries. Besides, the incorporation of PbS leads to the downward shift of the Fermi level for perovskite, which enhances hole collection within the device by optimizing band alignment at the perovskite/carbon interface. Consequently, an improved efficiency exceeding 20% is achieved for p‐MPSCs with no significant performance degradation observed over a storage period of 235 days. This strategy provides a facile and novel approach toward fabricating highly efficient and stable p‐MPSCs. [ABSTRACT FROM AUTHOR]

Few studies have examined young people’s attitudes toward death escape acceptance and its relationship to mindfulness. This study addressed this issue and examined the mediating role of emotion regulation. In Study 1, 61 undergraduate students aged 19–22 years participated in a mindfulness intervention program, and the results showed that increasing young people’s levels of mindfulness could improve their attitudes toward death escape acceptance. The Study 2, which recruited 440 young people aged 18–26 years to complete a cross-sectional survey, replicated the main effect and showed that young people’s difficulty in emotion regulation fully mediated the coping effect of mindfulness. These findings suggest that individuals with high levels of mindfulness may have low levels of difficulty in emotion regulation and in turn promote healthy attitudes toward death escape acceptance. [ABSTRACT FROM AUTHOR]

Printable mesoscopic perovskite solar cells (p-MPSCs) do not require the added hole-transport layer needed in traditional p-n junctions but have also exhibited lower power conversion efficiencies of about 19%. We performed device simulation and carrier dynamics analysis to design a p-MPSC with mesoporous layers of semiconducting titanium dioxide, insulating zirconium dioxide, and conducting carbon infiltrated with perovskite that enabled three-dimensional injection of photoexcited electrons into titanium dioxide for collection at a transparent conductor layer. Holes underwent long-distance diffusion toward the carbon back electrode, and this carrier separation reduced recombination at the back contact. Nonradiative recombination at the bulk titanium dioxide/perovskite interface was reduced by ammonium phosphate modification. The resulting p-MPSCs achieved a power conversion efficiency of 22.2% and maintained 97% of their initial efficiency after 750 hours of maximum power point tracking at 55 ± 5°C.

Background: Healthy diet is essential for cardiovascular disease risk management, but its effects among Chinese patients, whose diets differ from Western diets, remain largely unknown., Methods: In this multicenter, patient- and outcome assessor-blind, randomized controlled feeding trial, 265 Chinese adults with baseline systolic blood pressure 130 to 159 mmHg were randomly assigned into Chinese heart-healthy (CHH) diet or usual diet for a 28-d intervention after a 7-d run-in period on usual diet. Blood lipids and glucose were measured from overnight fasting blood samples before and after the intervention. Ten-year cardiovascular disease risk was estimated using models previously developed and validated in Chinese. The changes in secondary outcomes of serum total cholesterol (TC), blood glucose, and 10-y cardiovascular disease risk over the intervention period were compared between intervention groups, adjusting for center, among participants with baseline and follow-up blood samples available. Sensitivity analyses were done with further adjustment for baseline values and covariables; missing data imputed; and among per-protocol population., Results: Among 256 eligible participants (130 on CHH diet, 126 on control diet), 42% had hypercholesterolemia and 15% had diabetes at baseline. In the control group, TC and 10-y cardiovascular disease risk decreased after the intervention by 0.16 mmol/L and 0.91%, respectively, but blood glucose increased by 0.25 mmol/L. Compared with usual diet, the CHH diet lowered TC (-0.14 mmol/L, P = 0.017) and 10-y cardiovascular disease risk (-1.24%, P = 0.001) further. No effect on blood glucose was found. All sensitivity analyses confirmed the results on TC and 10-y cardiovascular disease risk, and analysis with multiple variables adjusted showed a borderline significant effect on blood glucose (-0.17 mmol/L, P = 0.051). The differences in intake of nutrients and food groups between intervention groups explained the results., Conclusions: The CHH diet reduced TC and 10-y cardiovascular disease risk and was likely to reduce blood glucose among Chinese adults with mild hypertension. Further studies with longer terms are warranted. This trial was registered at clinicaltrials.gov as NCT03882645., (Copyright © 2023 American Society for Nutrition. Published by Elsevier Inc. All rights reserved.)

Introduction: Learning burnout has a significant negative impact on students' academic performance and professional development, which has been exacerbated by the growing trend of problematic smartphone use, such as smartphone addiction, among young people. Recently, the literature on excessive social media use has revealed a critical role of fear of missing out. Objective The purpose of this study was to examine how fear of missing out affects smartphone addiction and its subsequent effect on learning burnout in college students., Methods: In Study 1, 352 medical students were recruited to complete a cross-sectional survey. In Study 2, 2,948 college students were recruited to complete a cross-sectional survey. Further in Study 3, 30 medical students were recruited into a mindfulness-based intervention program., Results: Study 1 preliminarily confirmed that fear of missing out was positively correlated with learning burnout. Study 2 then revealed a moderated mediation model showing that fear of missing out may increase smartphone addiction, which in turn affects their sleep quality and finally leads to learning burnout. This chain mediation model was moderated by the participants' level of mindfulness. To confirm the promoting role of mindfulness, Study 3 further confirmed that mindfulness training indeed can improve smartphone addiction and reduce learning burnout in medical students., Discussion: Theoretical and practical contributions were discussed, highlighting the effects of fear of missing out on smartphone addiction and a moderating role of mindfulness training., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Ye, Li, Liu, Zheng, Lin, Zeng, Lin, Zhu, Chen, Chen and Liu.)

SnO 2 is widely used as the electron transport layer (ETL) in n-i-p perovskite solar cells. However, the deep-level defects at the interface between SnO 2 and the perovskite film will lead to energy loss, reducing the open-circuit voltage. Therefore, the interface optimization is essential to raise the efficiency and enhance the stability of perovskite solar cells. In this work, we introduce NH 4 F into the SnO 2 electron transport layers, and the optimized SnO 2 films reduce the interface defect density, improve the charge extraction, and reveal a better energy-level arrangement. Compared to the conventional SnO 2 perovskite solar cell, the average V oc is improved by 70 mV with the champion efficiency up to 22.12%. Moreover, the unencapsulated F-doped SnO 2 perovskite solar cells show better thermal stability (maintained 86.2%) and humidity stability (maintained 80.8%) after 35 days.

Perovskite solar cells (PSCs) have achieved high efficiencies with diversified device architectures. In particular, printable mesoscopic PSC has attracted intensive research attention due to its simple fabrication process and superior stability. However, in the absence of hole conductors, the unfavorable energy band alignment between the perovskite and the carbon electrode usually leads to the reduction of device performance, especially the open-circuit voltage ( V OC ). Here, a p-type molecule, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), is utilized to post-treat the perovskite/carbon interface, which benefits the charge transfer and suppresses the charge recombination within the device. As a result, the post-treated device delivers a power conversion efficiency of 18.05% with an enhanced V OC of 1044 mV. This work provides a facile method for tuning the interfacial energy band alignment and improving performance of printable mesoscopic PSCs.