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Surface engineering based on ionic liquids for efficient and stable CsPbI3 perovskite solar cells

JOURNAL OF MATERIALS CHEMISTRY A 2024年第13期12卷 7847-7855页

作者： Rui, Dong Fu, Jianfei Chen, Qiaoyun Cao, Ji Wu, Wenting Chen, Lei Zhang, Jing Zhang, Zelong Zhou, Yi Song, Bo Soochow Univ Coll Chem Chem Engn & Mat Sci Lab Adv Optoelect Mat Suzhou Key Lab Novel Semicond Mat & Devices Suzhou 215123 Peoples R China NingboTech Univ Sch Mat Sci & Engn MSE Ningbo 315100 Peoples R China Changzhou Univ Natl Expt Demonstrat Ctr Mat Sci & Engn Sch Mat Sci & Engn Jiangsu Prov Cultivat base State Key Lab Photovolt Changzhou 213164 Jiangsu Peoples R China

All-inorganic perovskite CsPbI3 is widely recognized as a promising material for photovoltaic applications in single-junction or tandem solar cells. However, the spontaneous phase transition of CsPbI3 remains a crucial obstacle to commercialization. In this study, we propose a surface engineering approach using a tetra-n-butylammonium hexafluorophosphate (TBAPF(6)) ionic liquid to prevent the perovskite-to-non-perovskite phase transition induced by moisture. The experimental results demonstrate that by chemically bonding excess lead iodide (PbI2) with a tetrabutylammonium cation (TBA(+)), a low-dimensional stable and hydrophobic material called [TBA]PbI3 was achieved, which effectively enhances the stability of the CsPbI3 perovskite structure. Furthermore, we found that the hexafluorophosphate anion (PF6-) can effectively passivate surface iodine vacancies and interact with uncoordinated Pb2+. Consequently, the CsPbI3-based perovskite solar cells (C-PSCs) employing the TBAPF6 treatment achieved an impressive power conversion efficiency (PCE) of 17.47%. Moreover, the unencapsulated devices retained more than 70% of their initial PCE after being stored in ambient air for 168 hours.

关键词： Lead compounds

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Privacy-Preserving Ranked Spatial keyword Query in Mobile Cloud-Assisted Fog Computing

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2023年第6期22卷 3604-3618页

作者： Tong, Qiuyun Miao, Yinbin Li, Hongwei Liu, Ximeng Deng, Robert H. Xidian Univ Sch Cyber Engn Xian 710071 Peoples R China Zhejiang Univ Key Lab Blockchain & Cyberspace Governance Zhejia Hangzhou 310027 Peoples R China Univ Elect Sci & Technol China Sch Comp Sci & Engn Chengdu 610051 Peoples R China Fuzhou Univ Sch Math & Comp Sci Key Lab Informat Secur Network Syst Fuzhou 350108 Peoples R China Singapore Management Univ Sch Informat Syst Singapore 188065 Singapore

With the increasing popularity of GPS-equipped mobile devices in cloud-assisted fog computing scenarios, massive spatio-textual data is generated and outsourced to cloud servers for storage and analysis. Existing privacy-preserving range query or ranked keyword search schemes does not support a unified index, and are just applicable for the symmetric environment where all users sharing the same secret key. To solve this issue, we propose a Privacy-preserving Ranked Spatial keyword Query in mobile cloud-assisted Fog computing (PRSQ-F). Specifically, we design a novel comparable product encoding strategy that combines both spatial and textual conditions tightly to retrieve the objects in query range and with the highest textual similarity. Then, we use a new conversion protocol and attribute-based encryption to support privacy-preserving retrieval and malicious user traceability in the asymmetric environment where different query users have different keys. Furthermore, we construct an R-tree-based index to achieve faster-than-linear retrieval. Our formal security analysis shows that data security can be guaranteed. Our empirical experiments using a real-world dataset demonstrate the efficiency and feasibility of PRSQ-F.

关键词： Mobile cloud-assisted fog computing spatio-textual data privacy-preserving ranked spatial keyword query

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Controllable synthesis of chain-bead SiC whiskers from rice husk powders via molten-salt method

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advanced POWDER technology 2024年第6期35卷

作者： Chen, Yang Wu, Zhi Lou, Xiaoming Ding, Jun Deng, Chengji Yu, Chao Zhu, Hongxi Zhang, Tao Hunan Inst Technol Sch Mat Sci & Engn Hengyang 421002 Peoples R China Wuhan Univ Sci & Technol State Key Lab Refractories & Met Wuhan 430081 Peoples R China

In view of the current situation that morphology of SiC whiskers synthesized from rice husk is too single, in this work, the chain-bead SiC whiskers were successfully synthesized via a simple molten-salt method. The effects of heating temperature on the phase composition and morphology of the product were compared under the salt-free and molten-salt conditions. The results indicated that the liquid environment formed by molten salt could retain SiO2 in the product and promote the formation of cristobalite, inhibiting the formation of SiC. Compared with the SiC synthesized under salt-free condition (linear morphology), the SiC whiskers synthesized by the molten-salt method at 1400 degrees C showed a chain-bead morphology, which was composed of b-SiC stalks and round beads of amorphous SiO2 on the stalks. Finally, the formation mechanism of chain-bead SiC whiskers in the molten-salt environment was clarified. (c) 2024 The Society of Powder technology Japan. Published by Elsevier B.V. and The Society of Powder technology Japan. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

关键词： Chain-bead SiC whisker Rice husk powder Molten-salt synthesis Morphology

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Effect of Pr(NO₃)₃ doping on the characteristics of TC4 micro-arc oxidation coatings

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MATERIALS SCIENCE AND technology 2024年第7期40卷 517-527页

作者： Yang, Hongpei Yang, Biao Wang, Ping Li, Chao Yang, Shaolan Wang, Xiangjie Luo, Xu Zheng, Youping Southwest Petr Univ Sch New Energy & Mat Chengdu Peoples R China State Key Lab Vanadium & Titanium Resources Compre Panzhihua Peoples R China

Micro-arc oxidation coatings were prepared on the surface of TC4 by adding different contents of rare-earth compound Pr(NO3)(3) to the aluminate and phosphate-based electrolyte. The results showed that the change in oxidation voltage increased at first and then decreased with the raised of Pr(NO3)(3) addition. At 0.05 g L-1, the oxidation voltage reached the maximum, the number of discharge micropores decreased, while the size increased, the thickness and hardness of the coatings reached the peak values. The coatings mainly included Al2TiO5, anatase, gamma-Al2O3 and a little of Pr2O3. Pr(NO3)(3)-doped coatings showed excellent corrosion resistance in 3.5% NaCl electrochemical workstation and oilfield simulation fluid containing 5% NaCl, and the corrosion resistance of the coatings reached the best at 0.05 g L-1.

关键词： TC4 titanium alloy micro-arc oxidation Pr(NO3)(3) corrosion resistance

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The Effects of Oscillating Frequency on Microstructure and Hardness of W-Ni-Fe Refractory Alloy Sintered by Hot Oscillating Pressure

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advanced engineering MATERIALS 2024年第6期26卷 2301326-2301326页

作者： Gao, Ka Hu, Yanghu Zhang, Zixiang Ren, Chunyang Zhao, Wei Sun, Dejian Gao, Yang An, Linan Kong, Qingquan Univ Shanghai Sci & Technol Sch Mech Engn Shanghai 200093 Peoples R China China Natl Heavy Machinery Res Inst Co Ltd State Key Lab Met Extrus & Forging Equipment Techn Xian 710000 Peoples R China Changhai Hosp Dept Gen Med Shanghai 200000 Peoples R China Zhengzhou Univ Aeronaut Sch Mat Sci & Engn Zhengzhou 450015 Peoples R China Dongguan Univ Technol Sch Mech Engn Dongguan 523808 Peoples R China Chengdu Univ Sichuan Prov Engn Technol Res Ctr Powder Met Chengdu 610106 Peoples R China

90 W-7Ni-3Fe refractory alloys are first sintered by hot oscillating pressure (HOP) under different oscillating frequencies (0, 1, and 10 Hz) in this work. The effects of oscillating frequencies on the microstructure and Vickers hardness are investigated. With the oscillating frequency increasing, the relative density and hardness of refractory alloys are obviously improved. Especially, the alloy sintered at the oscillating frequency of 10 Hz had the highest relative density of approximately 98.9% and the smallest average grain size of 3.26 mu m. Moreover, the narrowest average thickness of the bonding phase is about 0.18 mu m, and the lowest tungsten contiguity is about 61.1%. Then its excellent hardness (456.8 HV30) is obtained, which is nearly 16.1% higher than that of the 0 Hz frequency alloy. The refractory alloy with high densification, small grain size, and good hardness could be obtained by HOP with a high oscillating frequency. W-Ni-Fe refractory alloy is prepared by hot oscillating pressure at different oscillating frequencies (0, 1, and 10 Hz). The higher relative density (98.9%) and excellent hardness (456.8 HV30) of sintered alloys with the narrowest average thickness bonding phase (0.18 mu m), lowest tungsten contiguity (61.1%), and smallest grain size (3.26 mu m) are significantly improved through higher oscillating frequency *** (c) 2024 WILEY-VCH GmbH

关键词： hardness hot oscillating pressure microstructure oscillating frequency W-Ni-Fe alloy

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Hydrogen embrittlement and failure mechanisms of multi-principal element alloys:A review

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Journal of Materials Science & technology 2022年第27期122卷 20-32页

作者： Xinfeng Li Jing Yin Jin Zhang Yanfei Wang Xiaolong Song Yong Zhang Xuechong Ren Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China College of Education for the Future Beijing Normal UniversityZhuhai 519087China School of Chemical Engineering&Technology China University of Mining and TechnologyXuzhou 221116China State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China National Center for Materials Service Safety University of Science and Technology BeijingBeijing 100083China

Multi-principal element alloys exhibit excellent physical,chemical and mechanical properties,and they are used as novel structural materials for potential applications in nuclear energy,hydrogen energy,and petrochemical ***,exposing components made of the alloys to service conditions related to the mentioned applications may induce hydrogen embrittlement(HE)as one of the typical failure *** this review,we report and summarize the progress in understanding HE in multi-principal element alloys,with a particular focus on high-entropy alloys(HEAs).The review focuses on four aspects:(1)hydrogen migration behavior(hydrogen dissolution,hydrogen diffusion,and hydrogen traps);(2)factors affecting HE(hydrogen concentration,alloy elements and microstructure);(3)tensile mechanical properties in the presence of hydrogen and micro-damage HE mechanisms;(4)the design concept for preventing hydrogen-induced mechanical *** differences in the HE behavior and failure mechanisms between HEAs and traditional alloys are compared and ***,specific research directions for further investigation of fundamental HE issues and a strategy for a simultaneous improvement in strength and HE resistance are identified.

关键词： Hydrogen embrittlement High-entropy alloy Hydrogen diffusion Mechanical property

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Rethinking Virtual Machines Live Migration for Memory Disaggregation 25

Rethinking Virtual Machines Live Migration for Memory Disagg...

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25th IEEE International Conference on Cluster Computing (CLUSTER)

作者： Jia, Xingguo Yu, Xingzi Wang, Yun Yu, Senhao Qi, Zhengwei Shanghai Jiao Tong Univ Shanghai Peoples R China Beijing Inst Technol Beijing Peoples R China

ISBN: (纸本)9798350307924

Resource underutilization has troubled data centers for several decades. Memory disaggregation provides an efficient way to improve memory utilization while leaving a missing puzzle piece on CPU underutilization. Live migration is an essential method for CPU resource reallocation. However, the state-of-the-art Virtual Machines (VM) live migration suffers from significant resource consumption. We discover the substantial potential for optimizing live migration in disaggregated memory systems. We propose Anemoi, a source management system incorporating VM live migration into memory disaggregation to fill in the missing piece. Disaggregated memory enables the read-only replica to be accessible from destination nodes, eliminating considerable network transmission for memory pages and saving migration time. Regarding the potential overwhelming memory consumption of duplicate read-only replicas, we design a dedicated compression algorithm. The evaluation shows that Anemoi reduces the network bandwidth use and the migration time by 69% and 83%, respectively, compared to VM live migration. The compression can achieve a space-saving of 83.6%.

关键词： Memory Disaggregation Virtualization Live Migration

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Efficiency Improvement of 6.78MHz Metamaterials for WPT System

Efficiency Improvement of 6.78MHz Metamaterials for WPT Syst...

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International Conference on Electrical Machines and Systems (ICEMS)

作者： Lihui Yan Huiming Gao Cancan Rong Zhijuan Liao Chenyang Xia Qiong Wang China University of Mining and Technology Xuzhou China

There are many applications for wireless power transfer (WPT), but as the transmission distance increases, the magnetic field energy decays and the transmission efficiency drops sharply. In this paper, a focused electromagnetic metamaterial (MM) unit is designed. When the operating frequency is 6.78 MHz, the permeability of the metamaterial unit is negative, and the purpose of focusing the magnetic field is achieved. The WPT system using a 3$\times$ 3 array metamaterial was established. Through simulation, the magnetic field diagram and transmission efficiency of WPT system with metamaterial slab varying different transmission distances are obtained. The magnetic field around the Rx coil is significantly improved after adding the MM slab. When the transmitting and receiving coils are 20cm apart, the transmission efficiency of the system is improved the most with 41.03%.

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Entropy and Enthalpy Co-Tuning Strategy in Cu2-yAgy(In0.06Sn0.94)Se2S System toward Excellent Thermoelectric Performance

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advanced FUNCTIONAL MATERIALS 2025年第15期35卷

作者： Zhang, Wanjia Wu, Fanshi Hua, Yezhen Nie, Haonan Xu, Pengfei Zhao, Wei Wang, Xiyang Bang, Shinhyo Guo, Xiaofeng Lou, Yue Xu, Biao Nanjing Univ Sci & Technol Dept Chem & Chem Engn Nanjing 210094 Peoples R China Jilin Univ Coll Chem State Key Lab Inorgan Synth & Preparat Chem Changchun 130012 Peoples R China Washington State Univ Dept Chem Pullman WA 99164 USA

With the reduction in size, nanoparticles (NPs) exhibit unique chemical and physical properties due to surface effects and size-dependent electronic bands. However, a significant challenge that limits their practical application is the tendency for grain growth at elevated temperatures. Herein, an entropic and enthalpic-co-stabilization strategy is employed in a series of high-entropy Cu2-yAgy(In0.06Sn0.94)Se2S materials. Remarkably, the grain size of these materials remains at 70 nm even after repeated tests up to 873 K. This stability has enabled to achieve an ultra-low thermal conductivity (kappa tot) of 0.22 W m-1 K-1, a record-high peak zT value of 1.76, and a high average zT value of 0.54 for nanostructured Cu1.73Ag0.27(In0.06Sn0.94)Se2S. Additionally, a high thermoelectric conversion efficiency of 4.5% for the segmented single-leg module and 3.8% for the 2-pair module at Delta T approximate to 460 K are achieved with the Cu2SnSe3-based material, marking its debut in thermoelectric power generation. These findings provide a paradigm to stabilize grain size and improve the thermoelectric performance of nano-sized high-entropy materials (HEMs), presenting a promising avenue for substantial advancements across various applications.

关键词： enthalpy entropy ligand retention nano-sized grain thermoelectric

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Waste Cigarette Butts-Derived Nitrogen-Doped Carbon Fibers Loaded with Ru Nanoparticles as an Efficient Cathode Catalyst for Lithium-Oxygen Batteries

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ACS SUSTAINABLE CHEMISTRY & engineering 2023年第24期11卷 9163-9171页

作者： Wang, Tianyuan Yin, Fusheng Fang, Yuling Sun, Chunwen China Univ Min & Technol Beijing Sch Chem & Environm Engn Beijing 100083 Peoples R China

Alow-cost fibrous porous nitrogen-doped carbon materialwas prepared from waste cigarette butts to solve the problems of lithium-oxygenbatteries. Low catalytic activity and high cost of cathode catalystshinderthe large-scale commercial application of lithium-oxygen (Li-O-2) batteries. In this work, waste cigarette butts, which inherentlyhave a porous fiber structure, were selected as the precursor of thecarbon material for the cathode catalyst of Li-O-2 *** porous nitrogen-doped carbon material was prepared by simple heattreatment of waste cigarette butts. The rich porous structure of theobtained carbon fiber material effectively enhances the diffusionof oxygen molecules and provides ample space for the discharge products.N doping in carbon fibers enhances the bifunctional catalytic activitytoward oxygen reduction reaction (ORR) and oxygen evolution reaction(OER), which was corroborated by density functional theory (DFT) *** assembled Li-O-2 battery with C-N fibers-loadedRu nanoparticles catalyst delivers an initial discharge capacity ofup to 12 036.3 mA h g(-1) and can be cycledstably for more than 800 cycles (4000 h) at a current density of 200mA g(-1) and a cutoff capacity of 500 mA h g(-1). Even at a high current density of 500 mA g(-1),the cells still show a high average discharge voltage of 2.28 V withexcellent cycle stability and rate capability. XPS analysis provesthat the cathode material can effectively inhibit the formation ofLi(2)CO(3) and Li2O byproducts. Thiswork provides a cost-effective solution to solve the cathode catalystproblem of Li-O-2 batteries and improve their cycling stabilityas well as environment protection.

关键词： waste utilization nitrogen-doped carbon bifunctionalcatalyst lithium-oxygen battery DFT calculation interface analysis

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