As the most promising lead‐free one, tin‐halides based perovskite solar cells still suffer from the severe bulk‐defect due to the easy oxidation of tin from divalent to tetravalent. Here, a general ...and effective strategy is delivered to modulate the microstructure of 2D/3D heterogeneous tin‐perovskite absorber films by substituting FAI with FPEABr in FASnI3. The introduction of 2D phase can induce highly oriented growth of 3D FASnI3 and it is revealed in the optimal 2D/3D film that 2D phase embraces 3D grains and locates at the surfaces and grain boundaries. The FPEA+ based 2D tin‐perovskite capping layer can offer a reducing atmosphere for vulnerable 3D FASnI3 grains. The unique microstructure effectively suppresses the well‐known oxidation from Sn2+ to Sn4+, as well as decreasing defect density, which leads to a remarkable enhanced device performance from 9.38% to 14.81% in conversion efficiency. The certified conversion efficiency of 14.03% announces a new record and moves a remarkable step from the last one (12.4%). Besides of this breakthrough, this work definitely paves a new way to fabricate high‐quality tin‐perovskite absorber film by constructing effective 2D/3D microstructures.
A general and effective strategy is delivered to modulate the 2D/3D microstructure of tin‐perovskite films by introduction of a 2D phase with the function of FPEABr, which induces high‐orientation growth of 3D FASnI3 by embracing the 3D grains at their surfaces and boundaries. That leads to a breakthrough of device performance of 14.81% in power conversion efficiency, along with 14.03% certified.
Blockchain is becoming popular as a distributed and reliable ledger which allows distrustful parties to transact safely without trusting third parties. Emerging blockchain systems like Ethereum ...support smart contracts where miners can run arbitrary user-defined programs. However, one of the biggest concerns about the blockchain and the smart contract is privacy, since all the transactions on the chain are exposed to the public. In this paper, we present ShadowEth, a system that leverages hardware enclave to ensure the confidentiality of smart contracts while keeping the integrity and availability based on existing public blockchains like Ethereum. ShadowEth establishes a confidential and secure platform protected by trusted execution environment (TEE) off the public blockchain for the execution and storage of private contracts. It only puts the process of verification on the blockchain. We provide a design of our system including a protocol of the cryptographic communication and verification and show the applicability and feasibility of ShadowEth by various case studies. We implement a prototype using the Intel SGX on the Ethereum network and analyze the security and availability of the system.
Abstract
Na-ion cathode materials operating at high voltage with a stable cycling behavior are needed to develop future high-energy Na-ion cells. However, the irreversible oxygen redox reaction at ...the high-voltage region in sodium layered cathode materials generates structural instability and poor capacity retention upon cycling. Here, we report a doping strategy by incorporating light-weight boron into the cathode active material lattice to decrease the irreversible oxygen oxidation at high voltages (i.e., >4.0 V vs. Na
+
/Na). The presence of covalent B–O bonds and the negative charges of the oxygen atoms ensures a robust ligand framework for the NaLi
1/9
Ni
2/9
Fe
2/9
Mn
4/9
O
2
cathode material while mitigating the excessive oxidation of oxygen for charge compensation and avoiding irreversible structural changes during cell operation. The B-doped cathode material promotes reversible transition metal redox reaction enabling a room-temperature capacity of 160.5 mAh g
−1
at 25 mA g
−1
and capacity retention of 82.8% after 200 cycles at 250 mA g
−1
. A 71.28 mAh single-coated lab-scale Na-ion pouch cell comprising a pre-sodiated hard carbon-based anode and B-doped cathode material is also reported as proof of concept.
As the most promising lead‐free branch, tin halide perovskites suffer from the severe oxidation from Sn2+ to Sn4+, which results in the unsatisfactory conversion efficiency far from what they ...deserve. In this work, by facile incorporation of methylammonium bromide in composition engineering, formamidinium and methylammonium mixed cations tin halide perovskite films with ultrahighly oriented crystallization are synthesized with the preferential facet of (001), and that oxidation is suppressed with obviously declined trap density. MA+ ions are responsible for that impressive orientation while Br‐ ions account for their bandgap modulation. Depending on high quality of the optimal MA0.25FA0.75SnI2.75Br0.25 perovskite films, their device conversion efficiency surges to 9.31% in contrast to 5.02% of the control formamidinium tin triiodide perovskite (FASnI3) device, along with almost eliminated hysteresis. That also results in the outstanding device stability, maintaining above 80% of the initial efficiency after 300 h of light soaking while the control FASnI3 device fails within 120 h. This paper definitely paves a facile and effective way to develop high‐efficiency tin halide perovskites solar cells, optoelectronic devices, and beyond.
MABr induces the remarkably oriented growth of tin halide perovskite films (MAxFA1−xSnI3−xBrx) by alloying, which results in an optimal device conversion efficiency of 9.31% enhanced from 5.02% of the pristine FASnI3 device and maintained above 80% of the initial efficiency after 300 h light soaking while the control device fails within 120 h.
Sodium‐ion batteries have gained much attention for their potential application in large‐scale stationary energy storage due to the low cost and abundant sodium sources in the earth. However, the ...electrochemical performance of sodium‐ion full cells (SIFCs) suffers severely from the irreversible consumption of sodium ions of cathode during the solid electrolyte interphase (SEI) formation of hard carbon anode. Here, a high‐efficiency cathode sodiation compensation reagent, sodium oxalate (Na2C2O4), which possesses both a high theoretical capacity of 400 mA h g−1 and a capacity utilization as high as 99%, is proposed. The implementation of Na2C2O4 as sacrificial sodium species is successfully realized by decreasing its oxidation potential from 4.41 to 3.97 V through tuning conductive additives with different physicochemical features, and the corresponding mechanism of oxidation potential manipulation is analyzed. Electrochemical results show that in the full cell based on a hard carbon anode and a P2‐Na2/3Ni1/3Mn1/3Ti1/3O2 cathode with Na2C2O4 as a sodium reservoir to compensate for sodium loss during SEI formation, the capacity retention is increased from 63% to 85% after 200 cycles and the energy density is improved from 129.2 to 172.6 W h kg−1. This work can provide a new avenue for accelerating the development of SIFCs.
The development of sodium‐ion batteries has been hindered so far by the irreversible consumption of sodium ions of the cathode during the solid electrolyte interphase formation. Therefore, in search of a safe, cost‐effective, and highly efficient cathode sodiation reagent, the feasibility of Na2C2O4 as a sodium reservoir source for enhancing the performance of sodium‐ion batteries is investigated.
The promising tin perovskite solar cells (PSCs) suffer from the oxidation of Sn2+ to Sn4+, leading to a disappointing conversion efficiency along with poor stability. In this work, ...phenylethylammonium bromide (PEABr) was employed to form an ultrathin, low‐dimensional perovskite layer on the surface of the FASnI3 (FA=formamidinium) absorber film to improve the interface of perovskite/PCBM (6,6‐phenyl‐C61‐butyricacid methyl) in the inverted planar device structure of the ITO (indium‐doped tin oxide)/PEDOT:PSS poly(3,4‐ethylenedioxythiophene)/polystyrene sulfonate/perovskite/6,6‐phenyl‐C61‐butyricacid methyl (PCBM)/BCP (2,9‐dimethyl‐4,7‐diphenyl‐1,10‐phenanthroline) electrode. The device efficiency was enhanced from 4.77 to 7.86 % by this PEABr treatment. A series of characterizations proved that this modification could improve the crystallinity of the FASnI3 perovskite by incorporating Br and forming an ultrathin, low‐dimensional perovskite layer at the interface, which led to the effective suppression of Sn2+ oxidation, improved band level alignment, and decreased defect density. These effects contributed to the clear enhancement of conversion efficiency. Moreover, this treatment also led to remarkably enhanced device stability, with approximately 80 % of the initial efficiency retained after 350 h light soaking, whereas the control device failed within 140 h. This work deepens our understanding of the suppression effect of PEABr on the oxidation of Sn2+ and paves a new way to fabricate promising tin halide PSCs by facile interface engineering.
Treat yo self: Phenylethylammonium bromide (PEABr) is employed to treat pristine FASnI3 (FA=formamidinium) films, leading to formation of an ultrathin low‐dimensional perovskite layer on the surface of the pristine film and Br incorporation into the bulk of the FASnI3 film. The treatment enhances stability and conversion efficiency from 4.77 to 7.86 %.
Covalent organic frameworks (COFs) are a class of organic crystalline porous materials discovered in the early 21st century that have become an attractive class of emerging materials due to their ...high crystallinity, intrinsic porosity, structural regularity, diverse functionality, design flexibility, and outstanding stability. However, many chemical and physical properties strongly depend on the presence of metal ions in materials for advanced applications, but metal-free COFs do not have these properties and are therefore excluded from such applications. Metalated COFs formed by combining COFs with metal ions, while retaining the advantages of COFs, have additional intriguing properties and applications, and have attracted considerable attention over the past decade. This review presents all aspects of metalated COFs, from synthetic strategies to various applications, in the hope of promoting the continued development of this young field.
This review highlights the recent advances of metalated covalent organic frameworks, including synthetic strategies and applications, and discusses the current challenges and future directions.
GetOrganelle is a state-of-the-art toolkit to accurately assemble organelle genomes from whole genome sequencing data. It recruits organelle-associated reads using a modified "baiting and iterative ...mapping" approach, conducts de novo assembly, filters and disentangles the assembly graph, and produces all possible configurations of circular organelle genomes. For 50 published plant datasets, we are able to reassemble the circular plastomes from 47 datasets using GetOrganelle. GetOrganelle assemblies are more accurate than published and/or NOVOPlasty-reassembled plastomes as assessed by mapping. We also assemble complete mitochondrial genomes using GetOrganelle. GetOrganelle is freely released under a GPL-3 license ( https://github.com/Kinggerm/GetOrganelle ).
The mammalian mitochondrial electron transport chain (ETc) includes complexes I-IV, as well as the electron transporters ubiquinone and cytochrome c. There are two electron transport pathways in the ...ETC: complex I/III/IV, with NAdH as the substrate and complex II/III/IV, with succinic acid as the substrate. The electron flow is coupled with the generation of a proton gradient across the inner membrane and the energy accumulated in the proton gradient is used by complex V (ATP synthase) to produce ATP. The first part of this review briefly introduces the structure and function of complexes I-IV and ATP synthase, including the specific electron transfer process in each complex. Some electrons are directly transferred to O.sub.2 to generate reactive oxygen species (ROS) in the ETC. The second part of this review discusses the sites of ROS generation in each ETC complex, including sites I.sub.F and I.sub.Q in complex I, site II.sub.F in complex II and site III.sub.Qo in complex III, and the physiological and pathological regulation of ROS. As signaling molecules, ROS play an important role in cell proliferation, hypoxia adaptation and cell fate determination, but excessive ROS can cause irreversible cell damage and even cell death. The occurrence and development of a number of diseases are closely related to ROS overproduction. Finally, proton leak and uncoupling proteins (UCP.sub.S) are discussed. Proton leak consists of basal proton leak and induced proton leak. Induced proton leak is precisely regulated and induced by UCPs. A total of five UCPs (UCP1-5) have been identified in mammalian cells. UCP1 mainly plays a role in the maintenance of body temperature in a cold environment through non-shivering thermogenesis. The core role of UcP2-5 is to reduce oxidative stress under certain conditions, therefore exerting cytoprotective effects. All diseases involving oxidative stress are associated with UCPs.
With ever‐increasing efforts focused on basic research of sodium‐ion batteries (SIBs) and growing energy demand, sodium‐ion full cells (SIFCs), as unique bridging technology between sodium‐ion ...half‐cells (SIHCs) and commercial batteries, have attracted more and more interest and attention. To promote the development of SIFCs in a better way, it is essential to gain a systematic and profound insight into their key issues and research status. This Review mainly focuses on the interface issues, major challenges, and recent progresses in SIFCs based on diversified electrolytes (i.e., nonaqueous liquid electrolytes, quasi‐solid‐state electrolytes, and all‐solid‐state electrolytes) and summarizes the modification strategies to improve their electrochemical performance, including interface modification, cathode/anode matching, capacity ratio, electrolyte optimization, and sodium compensation. Outlooks and perspectives on the future research directions to build better SIFCs are also provided.
Sodium‐ion full cells with low cost and abundant resource are promising to satisfy the urgent demand of large‐scale energy storage, yet their developments suffer from challenges of interfacial characteristics. Here, their recent advances in various electrolytes are summarized, and diverse strategies including tailoring interface, matching capacity, optimizing electrolyte as well as compensating sodium to drive the development of the whole industry are addressed.
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