Textured Perovskite/Silicon Tandem Solar Cells Achieving Over 30% Efficiency Promoted by 4-Fluorobenzylamine Hydroiodide

Monolithic textured perovskite/silicon tandem solar cells(TSCs)are expected to achieve maximum light capture at the lowest cost,potentially exhibiting the best power conversion efficiency.However,it is challenging to fabricate high-quality perovskite films and preferred crystal orientation on commercially textured silicon substrates with micrometersize pyramids.Here,we introduced a bulky organic molecule(4-fluorobenzylamine hydroiodide(F-PMAI))as a perovskite additive.It is found that F-PMAI can retard the crystallization process of perovskite film through hydrogen bond interaction between F^(−)and FA^(+)and reduce(111)facet surface energy due to enhanced adsorption energy of F-PMAI on the(111)facet.Besides,the bulky molecular is extruded to the bottom and top of perovskite film after crystal growth,which can passivate interface defects through strong interaction between F-PMA+and undercoordinated Pb^(2+)/I^(−).As a result,the additive facilitates the formation of large perovskite grains and(111)preferred orientation with a reduced trap-state density,thereby promoting charge carrier transportation,and enhancing device performance and stability.The perovskite/silicon TSCs achieved a champion efficiency of 30.05%based on a silicon thin film tunneling junction.In addition,the devices exhibit excellent longterm thermal and light stability without encapsulation.This work provides an effective strategy for achieving efficient and stable TSCs.

A new perspective to develop regiorandom polymer acceptors with high active layer ductility,excellent device stability,and high efficiency approaching 17%

The recently reported efficient polymerized small-molecule acceptors(PSMAs)usually adopt a regioregular backbone by polymerizing small-molecule acceptors precursors with a low-reactivity 5-brominated 3-(dicyanomethylidene)indan-1-one(IC)end group or its derivatives,leading to low molecular weight,and thus reduce active layer mechanical properties.Herein,a series of newly designed chlorinated PSMAs originating from isomeric IC end groups are developed by adjusting chlorinated positions and copolymerized sites on end groups to achieve high molecular weight,favorable intermolecular interaction,and improved physicochemical properties.Compared with regioregular PY2Se-Cl-o and PY2Se-Cl-m,regiorandom PY2Se-Cl-ran has a similar absorption profile,moderate lowest unoccupied molecular orbital level,and favorable intermolecular packing and crystallization properties.Moreover,the binary PM6:PY2Se-Cl-ran blend achieves better ductility with a crack-onset strain of 17.5% and improved power conversion efficiency(PCE)of 16.23% in all-polymer solar cells(all-PSCs)due to the higher molecular weight of PY2Se-Cl-ran and optimized blend morphology,while the ternary PM6:J71:PY2Se-Cl-ran blend offers an impressive PCE approaching 17% and excellent device stability,which are all crucial for potential practical applications of all-PSCs in wearable electronics.To date,the efficiency of 16.86% is the highest value reported for the regiorandom PSMAs-based all-PSCs and is also one of the best values reported for the all-PSCs.Our work provides a new perspective to develop efficient all-PSCs,with all high active layer ductility,impressive PCE,and excellent device stability,towards practical applications.

Cross-cultural Communication in English Language Teaching

Starting from the nature of cross-cultural communication, the author of this paper tentatively explores various cultural phenomena： cultural transmission, cultural diffusion, cultural blank, cultural shock and communication breakdown, etc. This paper points out that the success of cross-cultural communication depends on the competence of cross-cultural communication and gives some suggestions concerning the goals of foreign culture acquisition and the ways of culture training.

The status quo and future prospects of digital twins for healthcare

Digital twin technology plays a pivotal role in driving the digital transformation of healthcare services.This review provides a comprehensive overview of the applications of digital twins in the healthcare sector.We elucidate the concept and classification of digital twins for healthcare and provide a detailed account of their current applications in clinical diagnosis,treatment,and hospital operational management.Taking the cardiac digital twin as an example,this review showcases the typical use of digital twins in clinical practice and scientific research.Additionally,the challenges faced by digital twin technology in data collection,model construction,ethics,and regulations were analyzed.Finally,the broad prospects of digital twins in promoting precision and personalization in healthcare are envisioned.

靳希斌教育投资思想及其学术贡献

靳希斌先生是中国教育经济学主要开创者和奠基者之一,教育投资是教育经济学的核心内容之一,也是靳先生在教育经济学研究中一直关注的问题。本文基于对靳先生1981—2015年公开发表的论文和出版的著作中有关教育投资论述的文本分析,阐释其教育投资思想的形成逻辑及其学术贡献。靳先生教育投资思想源于对马克思主义经济、教育思想原著中教育投资论述的挖掘,演进于合理借鉴西方人力资本理论的教育投资观点,形成于关注中国教育经济、教育投资现实问题研究需要的应答,构建了具有中国特色的教育投资思想体系;靳先生教育投资思想的学术贡献涉及教育投资及性质论、教育投资体制论、教育投资比例论、教育投资效益论、教育投资外资利用与教育资本论等主题;靳先生基于理论的融合与中国教育实践的发展,推动教育投资研究中国化;基于国家发展战略,认识教育投资优先的重要性;基于中国现实发展动态,理解教育投资比例的合理性;基于高质量人才培养,探寻提升教育投资效益途径等教育投资思想具有重要的现实意义。

撼地者:基于遥操作与自主导航的移动救援机器人

为了应对突发场景及灾难环境下的救援作业任务,避免救援人员暴露在危险环境中,本论文提出一款移动救援机器人,“撼地者”。凭借履带式底盘、六自由度灵巧机械臂及各种传感器及控制器的组合,撼地者得以拥有跨越多样地形和完成精细作业的能力。具体来说,首先,撼地者独特的摆臂-推铲机构设计,在提高了清障能力的同时,增加了上下楼梯的稳定性;其次,通过多模态遥操作系统使撼地者得以适应各种复杂的通讯环境;同时,基于深度相机辅助的灵巧机械臂与抓手实现了半自主操纵;最终,利用激光雷达实现了在未知环境中的自主导航。正是凭借这些特别的系统,撼地者在以应急救援为主题的“智创杯”前沿技术挑战赛锦标赛中,从全球40个机器人中脱颖而出并成功夺冠,展示了其系统集成的有效性及控制理念的先进性。

Protective effect of oxysophoridine on cerebral ischemia/reperfusion injury in mice

Oxysophoridine, a new alkaloid extracted from Sophora alopecuroides L., has been shown to have a protective effect against ischemic brain damage. In this study, a focal cerebral ischemia/reperfusion injury model was established using middle cerebral artery occlusion in mice. Both 62.5, 125, and 250 mg/kg oxysophoridine, via intraperitoneal injection, and 6 mg/kg nimodipine, via intragastric administration, were administered daily for 7 days before modeling. After 24 hours of reperfusion, mice were tested for neurological deficit, cerebral infarct size was assessed and brain tissue was collected. Results showed that oxysophoridine at 125, 250 mg/kg and 6 mg/kg nimodipine could reduce neurological deficit scores, cerebral infarct size and brain water content in mice. These results provided evidence that oxysophoridine plays a protective role in cerebral ischemia/reperfusion injury. In addition, oxysophoridine at 62.5, 125, and 250 mg/kg and 6 mg/kg nimodipine increased adenosine-triphosphate content, and decreased malondialdehyde and nitric oxide content. These compounds enhanced the activities of glutathione-peroxidase, superoxide dismutase, catalase, and lactate dehydrogenase, and decreased the activity of nitric oxide synthase Protein and mRNA expression levels of N-methyI-D-aspartate receptor subunit NR1 were markedly inhibited in the presence of 250 mg/kg oxysophoridine and 6 mg/kg nimodipine. Our experimental findings indicated that oxysophoridine has a neuroprotective effect against cerebral ischemia/reperfusion injury in mice, and that the effect may be due to its ability to inhibit oxidative stress and expression of the N-methyI-D-aspartate receptor subunit NR1.

Green‑Solvent Processed Blade‑Coating Organic Solar Cells with an Efficiency Approaching 19%Enabled by Alkyl‑Tailored Acceptors

Power-conversion-efficiencies(PCEs)of organic solar cells(OSCs)in laboratory,normally processed by spin-coating technology with toxic halogenated solvents,have reached over 19%.However,there is usually a marked PCE drop when the bladecoating and/or green-solvents toward large-scale printing are used instead,which hampers the practical development of OSCs.Here,a new series of N-alkyl-tailored small molecule acceptors named YR-SeNF with a same molecular main backbone are developed by combining selenium-fused central-core and naphthalene-fused endgroup.Thanks to the N-alkyl engineering,NIR-absorbing YR-SeNF series show different crystallinity,packing patterns,and miscibility with polymeric donor.The studies exhibit that the molecular packing,crystallinity,and vertical distribution of active layer morphologies are well optimized by introducing newly designed guest acceptor associated with tailored N-alkyl chains,providing the improved charge transfer dynamics and stability for the PM6:L8-BO:YRSeNF-based OSCs.As a result,a record-high PCE approaching 19%is achieved in the blade-coating OSCs fabricated from a greensolvent o-xylene with high-boiling point.Notably,ternary OSCs offer robust operating stability under maximum-power-point tracking and well-keep>80%of the initial PCEs for even over 400 h.Our alkyl-tailored guest acceptor strategy provides a unique approach to develop green-solvent and blade-coating processed high-efficiency and operating stable OSCs,which paves a way for industrial development.

OsEIL1 and OsEIL2,two master regulators of rice ethylene signaling,promote the expression of ROS scavenging genes to facilitate coleoptile elongation and seedling emergence from soil

Successful emergence from the soil is a prerequisite for survival of germinating seeds in their natural envi-ronment.In rice,coleoptile elongation facilitates seedling emergence and establishment,and ethylene plays an important role in this process.However,the underlying regulatory mechanism remains largely unclear.Here,we report that ethylene promotes cell elongation and inhibits cell expansion in rice coleoptiles,result-ing in longer and thinner coleoptiles that facilitate seedlings emergence from the soil.Transcriptome analysis showed that genes related to reactive oxygen species(ROS)generation are upregulated and genes involved in ROS scavenging are downregulated in the coleoptiles of ethylene-signaling mutants.Further investiga-tions showed that soil coverage promotes accumulation of ETHYLENE INSENSITIVE 3-LIKE 1(OsEIL1)and OsEIL2 in the upper region of the coleoptile,and both OsEIL1 and OsEIL2 can bind directly to the promoters of the GDP-mannose pyrophosphorylase(VTC1)gene OsVTC1-3 and the peroxidase(PRX)genes OsPRX37,OsPRX81,OsPRX82,and OsPRX88 to activate their expression.This leads to increased ascorbic acid content,greater peroxidase activity,and decreased ROS accumulation in the upper region of the coleoptile.Disruption of ROS accumulation promotes coleoptile growth and seedling emergence from soil.Thesendings deepen our understanding of the roles of ethylene and ROS in controlling coleoptile growth,and this information can be used by breeders to produce rice varieties suitable for direct seeding.

Semicrystalline Unfused Polymer Donors with Backbone Halogenation toward Cost-Effective Organic Solar Cells

Developing novel unfused building blocks with simple synthesis and low cost is essential to advance and enrich cost-effective poly-mer donors;however,it remains a challenge due to the lack of efficient molecular strategies.Herein,a class of low-cost and fully unfused polymer donors with precisely regulated backbone planarity via halogenation was designed and synthesized,namely PDTBTBz-2H,PDTBTBz-2F,and PDTBTBz-2Cl.These polymer donors possess a four-step synthesis route with over 80%yield from cheap raw chemicals comparable to existing low-cost polymer donors,such as PTQ10.Benefitting from the planar backbone via in-corporating the F…S non-covalent interactions,PDTBTBz-2F exhibits more robust J-type aggregation in solution and a long-ranged molecular stacking in film relative to PDTBTBz-2H and PDTBTBz-2Cl.Moreover,the systematical study of PDTBTBz-based organic so-lar cells(OSCs)reveals the close relationship between optimized molecular self-assembly and charge separation/transport regarding backbone halogenation when paired with the non-fullerene acceptor(Y6-BO-4F).As a result,the photovoltaic devices based on semicrystalline PDTBTBz-2F achieved a promising power conversion efficiency(PCE)of 12.37%.Our work highlighted the influence of backbone halogenation on the molecular self-assembly properties and a potential unfused backbone motif for further developing cost-effective OSCs.

Transmissive 2-bit anisotropic coding metasurface

Coding metasurfaces have attracted tremendous interests due to unique capabilities of manipulating electromagnetic wave.However,archiving transmissive coding metasurface is still challenging.Here we propose a transmissive anisotropic coding metasurface that enables the independent control of two orthogonal polarizations.The polarization beam splitter and the orbital angular momentum(OAM)generator have been studied as typical applications of the anisotropic 2-bit coding metasurface.The simulated far field patterns illustrate that the x and y polarized electromagnetic waves are deflected into two different directions,respectively.The anisotropic coding metasurface has been experimentally verified to realize an OAM beam with l=2 of right-handed polarized wave,resulting from both contributions from linear-to-circular polarization conversion and the phase profile modulation.This work is beneficial to enrich the polarization manipulation field and develop transmissive coding metasurfaces.

Semi-crystalline photovoltaic polymers with siloxane-terminated hybrid side-chains

Three types of semi-cry stalline photovoltaic polymers were synthesized by incorporating a siloxane-terminated organic/inorganic hybrid side-chain and changing the number of fluorine substituents.A branch point away from a polymer main backbone in the siloxane-containing side-chains and the intra-and/or interchain noncovalent coulombic interactions enhance a chain planarity and facile interchain organization.The resulting polymers formed strongly agglomerated films with high roughness,suggesting strong intermolecular interactions.The optical band gap of ca.1.7 eV was measured for all polymers with a pronounced shoulder peak due to tight π-π stacking.With increasing the fluorine substituents,the frontier energy levels decreased and preferential face-on orientation was observed.The siloxane-terminated side-chains and fluorine substitution promoted the intermolecular packing,showing well resolved lamellar scatterings up to(300) for this series of polymers in the grazing incidence wide angle X-ray scattering measurements.The PPsiDTBT,PPsiDTFBT and PPsiDT2 FBT devices showed a power conversion efficiency of 3.16%,4.40%and 5.65%,respectively,by blending with PC_(71)BM.Langevin-type bimolecular charge recombination was similar for three polymeric solar cells.The main loss in the photocurrent generation for PPsiDTBT:PC_(71)BM was interpreted to originate from the trap assisted charge recombination by measuring light-intensity dependent short-circuit current density(J_(SC)) and open-circuit voltage(V_(Oc)).Our results provide a new insight into the rational selection of solubilizing substituents for optimizing crystalline interchain packing with appropriate miscibility with PC71 BM for further optimizing polymer solar cells.

基于有机混合离子-电子导体材料的有机电化学晶体管

作为有机生物电子学领域的重要功能器件,有机电化学晶体管因其高跨导、低工作电压和良好的生物相容性等优势,在神经形态计算、生物传感、逻辑电路等领域中展现出潜在的应用前景.近年来,得益于有机混合离子-电子导体材料的设计和开发,有机电化学晶体管的器件性能取得了快速提升,并成功推动了器件的多元化应用.本文结合有机电化学晶体管的工作原理和器件评价参数,梳理了有机混合离子-电子导体材料在侧链工程和骨架工程等方面的设计策略和发展现状,重点介绍了p/n型分子设计、器件性能和应用的研究进展,最后总结了高效稳定可商业化有机混合离子-电子材料开发和应用的挑战与机遇.

Trade-off analyses between food provision and soil conservation service of Grain for Green Program in Mountainous Area

The Grain for Green Program and soil and water conservation engineering initiatives are crucial for controlling erosion in steep-slope agriculture.However,it is still unclear how these two management methods should be carried out in respect to the situation in mountainous areas.Therefore,taking a typical mountainous area in southwest China as an example,we simulated six scenarios in order to compare the food provisioning service(FPS)and soil conservation service of the Grain for Green Program(converting to grassland)and Construction Measures(converting to sloping terrace)under different slopes.Results showed that when farmland with a>25°slope was converted into grassland,the amount of soil erosion(M)decreased by 21.0%,while FPS decreased by only 0.7%.However,when farmland with a>25°slope was converted into sloping terrace,M decreased by 31.3%while FPS increased by 18.7%.With the increases of farmland slope ranges in the Construction Measures scenario,M gradually decreased and FPS gradually increased.Particularly when farmland>15°was converted into sloping terrace,M decreased by 63.9%and FPS increased by 52.7%.Furthermore,the trade-offs of Construction Measures are lower than that of Grain for Green on different slope ranges.Therefore,we conclude that Construction Measures are a more suitable method in mountainous areas than the Grain for Green,and we suggest that further research be conducted to consider the ecological risks of construction engineering measures.

High-performance all-polymer solar cells enabled by a novel low bandgap non-fully conjugated polymer acceptor

The non-fully conjugated polymer as a new class of acceptor materials has shown some advantages over its small molecular counterpart when used in photoactive layers for all-polymer solar cells(all-PSCs),despite a low power conversion efficiency(PCE)caused by its narrow absorption spectra.Herein,a novel non-fully conjugated polymer acceptor PFY-2TS with a low bandgap of~1.40 eV was developed,via polymerizing a largeπ-fused small molecule acceptor(SMA)building block(namely YBO)with a non-conjugated thioalkyl linkage.Compared with its precursor YBO,PFY-2TS retains a similar low bandgap but a higher LUMO level.Moreover,compared with the structural analog of YBO-based fully conjugated polymer acceptor PFY-DTC,PFY-2TS shows a similar absorption spectrum and electron mobility,but significantly different molecular crystallinity and aggregation properties,which results in optimal blend morphology with a polymer donor PBDB-T and physical processes of the device in all-PSCs.As a result,PFY-2TS-based all-PSCs achieved a PCE of 12.31%with a small energy loss of 0.56 eV enabled by the reduced non-radiative energy loss(0.24 eV),which is better than that of 11.08%for the PFY-DTC-based ones.Our work clearly demonstrated that non-fully conjugated polymers as a new class of acceptor materials are very promising for the development of high-performance all-PSCs.

Polymerizing small molecular acceptors for efficient all-polymer solar cells

All-polymer solar cells(all-PSCs)have received attention due to their morphological stability under thermal and mechanical stresses.Currently,the highest reported power conversion efficiency of all-PSCs is over 17%,achieved by utilizing polymerized small molecular acceptors(PSMAs).However,the need for higher regiospecificity to avoid forming isomers during polymerization of SMAs still challenges the further applications of all-PSCs.From this perspective,we focus on some recent studies and highlight the importance of controlling the regioregularity of PSMAs.In particular,integrating PSMAs with regioregularity endows the polymer acceptors with good absorption,superior backbone ordering,and optimal blend morphology compared with those obtained from regiorandom one.Moreover,the distinctive features that are derived from these regioregular PSMAs,such as the possibility of repeatable synthesis and reproducible device performance,herald a brighter future for scaling-up and commercializing all-PSCs.We expect this integrated strategy will inspire researchers to devote more efforts to further narrow the efficiency gap between the PSCs based on SMAs and PSMAs.Finally,we discuss the existing challenges and future prospects of PSMAs as new platform for further advancing all-PSCs.

16.3%Efficiency binary all-polymer solar cells enabled by a novel polymer acceptor with an asymmetrical selenophene-fused backbone

Despite the significant progress made recently in all-polymer solar cells(all-PSCs),it is still quite challenging to achieve high open-circuit voltage(V_(oc))and short-circuit current density(J_(sc))simultaneously in order to further improve their performance.The recent strategy of using selenophene to replace thiophene on the Y6 based polymer acceptors has resulted in significantly improved J_(sc)s of the resulting all-PSCs.However,such modifications have also depressed V_(oc),which compromises the overall performance of the devices.Herein,we present the design and synthesis of a novel polymer acceptor,PYT-1S1Se,created by inserting an asymmetrical selenophene-fused framework to precisely manipulate optical absorption and electronic properties.Compared with the selenium-free analog,PYT-2S,and symmetrical selenium-fused analog,PYT-2Se,the PYT-1S1Se derived all-PSCs not only deliver optimized J_(sc)(24.1 mA cm^(−2))and V_(oc)(0.926 V)metrics,but also exhibit a relatively low energy loss of 0.502 eV.Consequently,these devices obtain a record-high power conversion efficiency(PCE)of 16.3%in binary all-PSCs.This work demonstrates an effective molecular design strategy for balancing the trade-off between V_(oc) and J_(sc) to achieve highefficiency all-PSCs.

Genomic analysis,trajectory tracking,and field surveys reveal sources and long-distance dispersal routes of wheat stripe rust pathogen in China

Identifying sources of phytopathogen inoculum and determining their contributions to disease outbreaks are essential for predicting disease development and establishing control strategies.Puccinia striiformis f.sp.tritici(Pst),the causal agent of wheat stripe rust,is an airborne fungal pathogen with rapid virulence variation that threatens wheat production through its long-distance migration.Because of wide variation in geographic features,climatic conditions,and wheat production systems,Pst sources and related dispersal routes in China are largely unclear.In the present study,we performed genomic analyses of 154 Pst isolates from all major wheat-growing regions in China to determine Pst population structure and diversity.Through trajectory tracking,historical migration studies,genetic introgression analyses,and field surveys,we investigated Pst sources and their contributions to wheat stripe rust epidemics.We identified Longnan,the Himalayan region,and the Guizhou Plateau,which contain the highest population genetic diversities,as the Pst sources in China.Pst from Longnan disseminates mainly to eastern Liupan Mountain,the Sichuan Basin,and eastern Qinghai;that from the Himalayan region spreads mainly to the Sichuan Basin and eastern Qinghai;and that from the Guizhou Plateau migrates mainly to the Sichuan Basin and the Central Plain.These findings improve our current understanding of wheat stripe rust epidemics in China and emphasize the need for managing stripe rust on a national scale.

Highly sensitive torsion sensor based on triangular-prism-shaped long-period fiber gratings

We propose and investigate a compact optical fiber sensor that aims to measure the torsion in both amount and direction with high sensitivity.This sensor is configured by a triangular-prism-shaped long-period fiber grating,which is fabricated by the high frequency CO_(2) laser polished method.The unique design of the triangular-shaped structure breaks the rotational symmetry of the optical fiber and provides high sensitivity for torsion measurement.In preliminary experiments,the torsion response of the sensor achieves a good stability and linearity.The torsion sensitivity is 0.54 nm/(rad/m),which renders the proposed structure a highly sensitive torsion sensor.

Computational Approaches and Challenges in Spatial Transcriptomics

The development of spatial transcriptomics(ST)technologies has transformed genetic research from a single-cell data level to a two-dimensional spatial coordinate system and facilitated the study of the composition and function of various cell subsets in different environments and organs.The large-scale data generated by these ST technologies,which contain spatial gene expression information,have elicited the need for spatially resolved approaches to meet the requirements of computational and biological data interpretation.These requirements include dealing with the explosive growth of data to determine the cell-level and gene-level expression,correcting the inner batch effect and loss of expression to improve the data quality,conducting efficient interpretation and in-depth knowledge mining both at the single-cell and tissue-wide levels,and conducting multi-omics integration analysis to provide an extensible framework toward the in-depth understanding of biological processes.However,algorithms designed specifically for ST technologies to meet these requirements are still in their infancy.Here,we review computational approaches to these problems in light of corresponding issues and challenges,and present forward-looking insights into algorithm development.