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991.
Air‐Stable Cesium Lead Iodide Perovskite for Ultra‐Low Operating Voltage Resistive Switching
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Ji Su Han Quyet Van Le Jaeho Choi Kootak Hong Cheon Woo Moon Taemin Ludvic Kim Hyojung Kim Soo Young Kim Ho Won Jang 《Advanced functional materials》2018,28(5)
CsPbX3 (X = halide, Cl, Br, or I) all‐inorganic halide perovskites (IHPs) are regarded as promising functional materials because of their tunable optoelectronic characteristics and superior stability to organic–inorganic hybrid halide perovskites. Herein, nonvolatile resistive switching (RS) memory devices based on all‐inorganic CsPbI3 perovskite are reported. An air‐stable CsPbI3 perovskite film with a thickness of only 200 nm is successfully synthesized on a platinum‐coated silicon substrate using low temperature all‐solution process. The RS memory devices of Ag/polymethylmethacrylate (PMMA)/CsPbI3/Pt/Ti/SiO2/Si structure exhibit reproducible and reliable bipolar switching characteristics with an ultralow operating voltage (<+0.2 V), high on/off ratio (>106), reversible RS by pulse voltage operation (pulse duration < 1 ms), and multilevel data storage. The mechanical flexibility of the CsPbI3 perovskite RS memory device on a flexible substrate is also successfully confirmed. With analyzing the influence of phase transition in CsPbI3 on RS characteristics, a mechanism involving conducting filaments formed by metal cation migration is proposed to explain the RS behavior of the memory device. This study will contribute to the understanding of the intrinsic characteristics of IHPs for low‐voltage resistive switching and demonstrate the huge potential of them for use in low‐power consumption nonvolatile memory devices on next‐generation computing systems. 相似文献
992.
以硅酸钾溶液与硅溶胶的反应物为基料,选用四甲基氢氧化铵对硅丙乳液进行催化水解,并以适度水解的硅丙乳液改性硅酸钾溶液与硅溶胶基料,通过有机-无机杂化的方式将其与1:2.6的锌粉进行混合,制备了一种水性无机硅酸钾富锌涂料。考察了模数、固含量、经适度水解的硅丙乳液掺量等对水性无机富锌涂料性能的影响,并对相关作用机理进行了分析。结果表明:当硅酸钾模数 为3.3,硅酸钾溶液固含量为25.0%,经适度水解的硅丙乳液的添加量为硅酸钾溶液固含量的5%~10%时,涂膜的硬度为5H,柔韧性为4mm,附着力为1级,7d耐水性和耐人工海水性能较好,所配制涂料的综合性能最优。 相似文献
993.
The aim of this article is to observe anomalous behaviour of strong acid cation (SAC) exchanger in VVER and PWR power plants. This ion exchanger is a part of primary water coolant purification system and shows a non-standard operation in the end of the fuel cycle during high-performance effect. This behaviour consists in process’ changes of potassium cation capture from boric acid solution, which is a major chemical of primary cooling water. The experiments were conducted under laboratory conditions on ion exchanger type DOWEX HCR-S NG and the samples with different concentrations of analytes (K+, NH4+, Li+, H3BO3) were measured. The results confirmed the anomalous behaviour of ion exchanger during high-performance effect when the potassium ions are captured on SAC due to its size and the lack of boric acid in water coolant. Therefore, the potassium hydroxide must be dosed into the primary water to control the content of alkali metals. 相似文献
994.
同位素稀释质谱法测定酸雨标准物质中微量钾和镁 总被引:2,自引:1,他引:2
本文叙述了同位素稀释质谱法(IDMS)测量微量钾和镁的方法,并用该法对酸雨标准物质中含量在10-8~10-7量级的钾和镁进行了测定,同时对如何减小污染、降低空白、提高测量精度等问题进行了研究。 相似文献
995.
996.
Ranjusha Rajagopalan Yougen Tang Xiaobo Ji Chuankun Jia Haiyan Wang 《Advanced functional materials》2020,30(12)
Demand for energy in day to day life is increasing exponentially. However, existing energy storage technologies like lithium ion batteries cannot stand alone to fulfill future needs. In this regard, potassium ion batteries (KIBs) that utilize K ions in their charge storage mechanism have attracted considerable attention due to their unique properties and are therefore established as one of the future battery systems of interest among the scientific community. Nevertheless, the development and identification of appropriate electrode materials is very essential for practical applications. This review features the current development in KIBs electrode and electrolyte materials, the present challenges facing this technology (in the commercial aspect), and future aspects to develop fully functional KIBs. The potassium storage mechanisms, evolution of the KIBs, and the advantages and disadvantages of each category of materials are included. Additionally, various approaches to enhance the electrochemical performances of KIBs are also discussed. This review is not only an amalgamation of different viewpoints in literature, but also contains concise perspectives and strategies. Moreover, the potential emergence of a novel class of K‐based dual ion batteries is also analyzed for the first time. 相似文献
997.
Cheng Li Antonio Guerrero Yu Zhong Anna Gräser Carlos Andres Melo Luna Jürgen Köhler Juan Bisquert Richard Hildner Sven Huettner 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(42)
Organic–inorganic metal halide perovskites (e.g., CH3NH3PbI3?x Clx ) emerge as a promising optoelectronic material. However, the Shockley–Queisser limit for the power conversion efficiency (PCE) of perovskite‐based photovoltaic devices is still not reached. Nonradiative recombination pathways may play a significant role and appear as photoluminescence (PL) inactive (or dark) areas on perovskite films. Although these observations are related to the presence of ions/defects, the underlying fundamental physics and detailed microscopic processes, concerning trap/defect status, ion migration, etc., still remain poorly understood. Here correlated wide‐field PL microscopy and impedance spectroscopy are utilized on perovskite films to in situ investigate both the spatial and the temporal evolution of these PL inactive areas under external electric fields. The formation of PL inactive domains is attributed to the migration and accumulation of iodide ions under external fields. Hence, we are able to characterize the kinetic processes and determine the drift velocities of these ions. In addition, it is shown that I2 vapor directly affects the PL quenching of a perovskite film, which provides evidence that the migration/segregation of iodide ions plays an important role in the PL quenching and consequently limits the PCE of organometal halide‐based perovskite photovoltaic devices. 相似文献
998.
Tongtong Miao Xiufeng Ju Qiuning Zhu Yamei Wang Qian Guo Tao Sun Chunzhu Lu Liang Han 《Advanced functional materials》2019,29(27)
Brain metastases are one of the most difficult malignancies to treat owing to their location and mostly multifocal and infiltrative growth. Chemotherapy, which is often effective against tumors outside the brain, offers some hope for brain metastases. However, the efficacy of systemic drug delivery to brain metastases is extremely limited due largely to the blood–brain tumor barrier (BTB). Herein, it is reported that minoxidil‐loaded hyaluronic acid–tethered nanoparticles (M@H‐NPs) can efficiently and specially surmount the BTB through both transcellular and paracellular pathways and target brain metastases through coordination of hyaluronic acid with CD44 target. The transcellular endocytosis, paracellular claudin‐5 expression, and BTB crossing are evaluated to confirm that the developed M@H‐NPs can be endued with minoxidil's ability to boost transcytosis and downregulate tight junction protein in BTB endothelial cells at brain metastases for promoted BTB penetration. M@H‐NPs selectively deliver doxorubicin (DOX) to brain metastatic lesions, while sparing normal brain cells from harm. Treatment with M@H‐NPs/DOX significantly prolongs median survival of mice bearing brain metastases. Due to the fruitful BTB penetration and brain metastasis homing, and improved therapeutic outcome, the minoxidil‐based systemic drug delivery strategy may serve as a potential approach for clinical management of brain metastases. 相似文献
999.
Gil Yong Lee Moon Young Yang Dong‐Ha Kim Joonwon Lim Jinwoo Byun Dong Sung Choi Ho Jin Lee Yoon Sung Nam Il‐Doo Kim Sang Ouk Kim 《Advanced functional materials》2019,29(30)
Interfacial engineering of organic–inorganic halide perovskites in conjunction with different functional materials is anticipated to offer novel heterojunction structures with unique functionalities. Unfortunately, complex material compositions and structures of the organic–inorganic hybrid materials make it difficult to tailor a desirable intermolecular interaction at the interface. Spontaneous and highly specific nucleation of perovskite crystals, that is, methylammonium lead iodide perovskite (CH3NH3PbI3, MAPbI3) at nitrogen‐doped carbon nanotube (NCNT) surfaces for the self‐assembly of MAPbI3/NCNT hybrids is reported. It is demonstrated that the lone‐pair electrons of pyridinic nitrogen‐dopant sites at NCNTs mediate specific interactions with the cationic component in the perovskite structure and serve as the nucleation sites via coordinate bonding formation, as supported by X‐ray photoelectron spectroscopy and density functional theory calculation. The potential suitability of MAPbI3/NCNT hybrids is presented for highly sensitive and selective NO2 sensing layer. This work suggests a reliable self‐assembly route to the molecular level hybridization of organic–inorganic halide perovskites by employing the substitutional dopant sites at graphene‐based nanomaterials. 相似文献
1000.
In‐Hyeok Park Leiqiang Chu Kai Leng Yu Fong Choy Wei Liu Ibrahim Abdelwahab Ziyu Zhu Zhirui Ma Wei Chen Qing‐Hua Xu Goki Eda Kian Ping Loh 《Advanced functional materials》2019,29(39)
Hybrid organic–inorganic perovskites have recently emerged as potential disruptive photovoltaic technology. However, the toxicity of lead used in state‐of‐the‐art hybrid perovskites solar cell prevents large‐scale commercialization, which calls for lead‐free alternatives. Sn‐based perovskites have been considered as alternatives but they are limited by rapid oxidation and decomposition in ambient air. Here, an Sn‐based two‐dimensional hybrid organic–inorganic perovskites [A2B(n‐1)SnnI(3n+1)] (n = 1 and 2) are reported with improved air stability, using bulky stilbene derivatives as the organic cations (2‐(4‐(3‐fluoro)stilbenyl)ethanammonium iodide (FSAI)). The moisture stability of the [(FSA)2SnI4] perovskites is attributed to the hydrophobic properties of fluorine‐functionalized organic chains (FSA), as well as the strong cohesive bonding in the organic chains provided by H bonds, CH···X type H bonds, weak interlayer F···F interaction, and weak face‐to‐face type π‐π interactions. The photodetector device fabricated on exfoliated single crystal flake of [(FSA)2SnI4] exhibits fast and stable photoconductor response. 相似文献