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1.
Kan Zhang Bingjun Jin Yujie Gao Shengli Zhang Hyunjung Shin Haibo Zeng Jong Hyeok Park 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(8)
1T‐phase molybdenum disulfide (1T‐MoS2) exhibits superior hydrogen evolution reaction (HER) over 2H‐phase MoS2 (2H‐MoS2). However, its thermodynamic instability is the main drawback impeding its practical application. In this work, a stable 1T‐MoS2 monolayer formed at edge‐aligned 2H‐MoS2 and a reduced graphene oxide heterointerface (EA‐2H/1T/RGO) using a precursor‐in‐solvent synthesis strategy are reported. Theoretical prediction indicates that the edge‐aligned layer stacking can induce heterointerfacial charge transfer, which results in a phase transition of the interfacial monolayer from 2H to 1T that realizes thermodynamic stability based on the adhesion energy between MoS2 and graphene. As an electrocatalyst for HER, EA‐2H/1T/RGO displays an onset potential of ?103 mV versus RHE, a Tafel slope of 46 mV dec?1 and 10 h stability in acidic electrolyte. The unexpected activity of EA‐2H/1T/RGO beyond 1T‐MoS2 is due to an inherent defect caused by the gliding of S atoms during the phase transition from 2H to 1T, leading the Gibbs free energy of hydrogen adsorption (ΔGH*) to decrease from 0.13 to 0.07 eV, which is closest to the ideal value (0.06 eV) of 2H‐MoS2. The presented work provides fundamental insights into the impressive electrochemical properties of HER and opens new avenues for phase transitions at 2D/2D hybrid interfaces. 相似文献
2.
Misorientation‐Angle‐Dependent Phase Transformation in van der Waals Multilayers via Electron‐Beam Irradiation
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Un Jeong Kim Hyangsook Lee Woojin Lee Hye Yun Jeong Hyun Kim Gang Hee Han Hyo Sug Lee Yeonsang Park Young‐Geun Roh Young Hee Lee Eunha Lee Sung Woo Hwang 《Advanced materials (Deerfield Beach, Fla.)》2018,30(20)
Misorientation‐angle dependence on layer thickness is an intriguing feature of van der Waals materials, which causes stark optical gain and electrical transport modulation. However, the influence of misorientation angle on phase transformation is not determined yet. Herein, this phenomenon in a MoS2 multilayer via in situ electron‐beam irradiation is reported. An AA′‐stacked MoS2 bilayer undergoes structural transformation from the 2H semiconducting phase to the 1T′ metallic phase, similar to a MoS2 monolayer, which is confirmed via in situ transmission electron microscopy. Moreover, non‐AA′ stacking, which has no local AA′ stacking order in the Moiré pattern, does not reveal such a phase transformation. While a collective sliding motion of chalcogen atoms easily occurs during the transformation in AA′ stacking, in non‐AA′ stacking it is suppressed by the weak van der Waals strength and by the chalcogen atoms interlocked at different orientations, which disfavor their kinetics by the increased entropy of mixing. 相似文献
3.
Ziwei Li Changxu Liu Xin Rong Yang Luo Haotian Cheng Liheng Zheng Feng Lin Bo Shen Yongji Gong Shuang Zhang Zheyu Fang 《Advanced materials (Deerfield Beach, Fla.)》2018,30(34)
Transition metal dichalcogenides with intrinsic spin–valley degrees of freedom hold great potentials for applications in spintronic and valleytronic devices. MoS2 monolayer possesses two inequivalent valleys in the Brillouin zone, with each valley coupling selectively with circularly polarized photons. The degree of valley polarization (DVP) is a parameter to characterize the purity of valley‐polarized photoluminescence (PL) of MoS2 monolayer. Usually, the detected values of DVP in MoS2 monolayer show achiral property under optical excitation of opposite helicities due to reciprocal phonon‐assisted intervalley scattering process. Here, it is reported that valley‐polarized PL of MoS2 can be tailored through near‐field interaction with plasmonic chiral metasurface. The resonant field of the chiral metasurface couples with valley‐polarized excitons, and tailors the measured PL spectra in the far‐field, resulting in observation of chiral DVP of MoS2‐metasurface under opposite helicities excitations. Valley‐contrast PL in the chiral heterostructure is also observed when illuminated by linearly polarized light. The manipulation of valley‐polarized PL in 2D materials using chiral metasurface represents a viable route toward valley‐polaritonic devices. 相似文献
4.
Gram‐Scale Aqueous Synthesis of Stable Few‐Layered 1T‐MoS2: Applications for Visible‐Light‐Driven Photocatalytic Hydrogen Evolution
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Qin Liu Xiuling Li Qun He Adnan Khalil Daobin Liu Ting Xiang Xiaojun Wu Li Song 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(41):5556-5564
Most recently, much attention has been devoted to 1T phase MoS2 because of its distinctive phase‐engineering nature and promising applications in catalysts, electronics, and energy storage devices. While alkali metal intercalation and exfoliation methods have been well developed to realize unstable 1T‐MoS2, but the aqueous synthesis for producing stable metallic phase remains big challenging. Herein, a new synthetic protocol is developed to mass‐produce colloidal metallic 1T‐MoS2 layers highly stabilized by intercalated ammonium ions (abbreviated as N‐MoS2). In combination with density functional calculations, the X‐ray diffraction pattern and Raman spectra elucidate the excellent stability of metallic phase. As clearly depicted by high‐angle annular dark‐field imaging in an aberration‐corrected scanning transmission electron microscope and extended X‐ray absorption fine structure, the N‐MoS2 exhibits a distorted octahedral structure with a 2a 0 × a 0 basal plane superlattice and 2.72 Å Mo–Mo bond length. In a proof‐of‐concept demonstration for the obtained material's applications, highly efficient photocatalytic activity is achieved by simply hybridizing metallic N‐MoS2 with semiconducting CdS nanorods due to the synergistic effect. As a direct outcome, this CdS:N‐MoS2 hybrid shows giant enhancement of hydrogen evolution rate, which is almost 21‐fold higher than pure CdS and threefold higher than corresponding annealed CdS:2H‐MoS2. 相似文献
5.
Zhi‐Qian Wu Jing‐Liang Yang Nallappagar K. Manjunath Yue‐Jiao Zhang Si‐Rui Feng Yang‐Hua Lu Jiang‐Hong Wu Wei‐Wei Zhao Cai‐Yu Qiu Jian‐Feng Li Shi‐Sheng Lin 《Advanced materials (Deerfield Beach, Fla.)》2018,30(27)
2D materials hold great potential for designing novel electronic and optoelectronic devices. However, 2D material can only absorb limited incident light. As a representative 2D semiconductor, monolayer MoS2 can only absorb up to 10% of the incident light in the visible, which is not sufficient to achieve a high optical‐to‐electrical conversion efficiency. To overcome this shortcoming, a “gap‐mode” plasmon‐enhanced monolayer MoS2 fluorescent emitter and photodetector is designed by squeezing the light‐field into Ag shell‐isolated nanoparticles–Au film gap, where the confined electromagnetic field can interact with monolayer MoS2. With this gap‐mode plasmon‐enhanced configuration, a 110‐fold enhancement of photoluminescence intensity is achieved, exceeding values reached by other plasmon‐enhanced MoS2 fluorescent emitters. In addition, a gap‐mode plasmon‐enhanced monolayer MoS2 photodetector with an 880% enhancement in photocurrent and a responsivity of 287.5 A W?1 is demonstrated, exceeding previously reported plasmon‐enhanced monolayer MoS2 photodetectors. 相似文献
6.
Ik Seon Kwon Tekalign Terfa Debela In Hye Kwak Yun Chang Park Jaemin Seo Ju Yong Shim Seung Jo Yoo Jin‐Gyu Kim Jeunghee Park Hong Seok Kang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(13)
2D MoS2 nanostructures have recently attracted considerable attention because of their outstanding electrocatalytic properties. The synthesis of unique Co–Ru–MoS2 hybrid nanosheets with excellent catalytic activity toward overall water splitting in alkaline solution is reported. 1T′ phase MoS2 nanosheets are doped homogeneously with Co atoms and decorated with Ru nanoparticles. The catalytic performance of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is characterized by low overpotentials of 52 and 308 mV at 10 mA cm?2 and Tafel slopes of 55 and 50 mV decade?1 in 1.0 m KOH, respectively. Analysis of X‐ray photoelectron and absorption spectra of the catalysts show that the MoS2 well retained its metallic 1T′ phase, which guarantees good electrical conductivity during the reaction. The Gibbs free energy calculation for the reaction pathway in alkaline electrolyte confirms that the Ru nanoparticles on the Co‐doped MoS2 greatly enhance the HER activity. Water adsorption and dissociation take place favorably on the Ru, and the doped Co further catalyzes HER by making the reaction intermediates more favorable. The high OER performance is attributed to the catalytically active RuO2 nanoparticles that are produced via oxidation of Ru nanoparticles. 相似文献
7.
8.
Thermodynamically Stable Synthesis of Large‐Scale and Highly Crystalline Transition Metal Dichalcogenide Monolayers and their Unipolar n–n Heterojunction Devices
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Juwon Lee Sangyeon Pak Paul Giraud Young‐Woo Lee Yuljae Cho John Hong A‐Rang Jang Hee‐Suk Chung Woong‐Ki Hong Hu Young Jeong Hyeon Suk Shin Luigi G. Occhipinti Stephen M. Morris SeungNam Cha Jung Inn Sohn Jong Min Kim 《Advanced materials (Deerfield Beach, Fla.)》2017,29(33)
Transition metal dichalcogenide (TMDC) monolayers are considered to be potential materials for atomically thin electronics due to their unique electronic and optical properties. However, large‐area and uniform growth of TMDC monolayers with large grain sizes is still a considerable challenge. This report presents a simple but effective approach for large‐scale and highly crystalline molybdenum disulfide monolayers using a solution‐processed precursor deposition. The low supersaturation level, triggered by the evaporation of an extremely thin precursor layer, reduces the nucleation density dramatically under a thermodynamically stable environment, yielding uniform and clean monolayer films and large crystal sizes up to 500 µm. As a result, the photoluminescence exhibits only a small full‐width‐half‐maximum of 48 meV, comparable to that of exfoliated and suspended monolayer crystals. It is confirmed that this growth procedure can be extended to the synthesis of other TMDC monolayers, and robust MoS2/WS2 heterojunction devices are easily prepared using this synthetic procedure due to the large‐sized crystals. The heterojunction device shows a fast response time (≈45 ms) and a significantly high photoresponsivity (≈40 AW?1) because of the built‐in potential and the majority‐carrier transport at the n–n junction. These findings indicate an efficient pathway for the fabrication of high‐performance 2D optoelectronic devices. 相似文献
9.
Yangyang Feng Ting Zhang Jiahui Zhang Hao Fan Cheng He Jiangxuan Song 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(33)
Metallic phase (1T) MoS2 has been regarded as an appealing material for hydrogen evolution reaction. In this work, a novel interface‐induced strategy is reported to achieve stable and high‐percentage 1T MoS2 through highly active 1T‐MoS2/CoS2 hetero‐nanostructure. Herein, a large number of heterointerfaces can be obtained by interlinked 1T‐MoS2 and CoS2 nanosheets in situ grown from the molybdate cobalt oxide nanorod under moderate conditions. Owing to the strong interaction between MoS2 and CoS2, high‐percentage of metallic‐phase (1T) MoS2 of 76.6% can be achieved, leading to high electroconductivity and abundant active sites compared to 2H MoS2. Furthermore, the interlinked MoS2 and CoS2 nanosheets can effectively disperse the nanosheets so as to enlarge the exposed active surface area. The near zero free energy of hydrogen adsorption at the heterointerface can also be achieved, indicating the fast kinetics and excellent catalytic activity induced by heterojunction. Therefore, when applied in hydrogen evolution reaction (HER), 1T‐MoS2/CoS2 heterostructure delivers low overpotential of 71 and 26 mV at the current density of 10 mA cm?2 with low Tafel slops of 60 and 43 mV dec?1, respectively in alkaline and acidic conditions. 相似文献
10.
Dongdong Zhu Jinlong Liu Yongqiang Zhao Yao Zheng Shi‐Zhang Qiao 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(14)
2D metal–organic frameworks (MOFs) have been widely investigated for electrocatalysis because of their unique characteristics such as large specific surface area, tunable structures, and enhanced conductivity. However, most of the works are focused on oxygen evolution reaction. There are very limited numbers of reports on MOFs for hydrogen evolution reaction (HER), and generally these reported MOFs suffer from unsatisfactory HER activities. In this contribution, novel 2D Co‐BDC/MoS2 (BDC stands for 1,4‐benzenedicarboxylate, C8H4O4) hybrid nanosheets are synthesized via a facile sonication‐assisted solution strategy. The introduction of Co‐BDC induces a partial phase transfer from semiconducting 2H‐MoS2 to metallic 1T‐MoS2. Compared with 2H‐MoS2, 1T‐MoS2 can activate the inert basal plane to provide more catalytic active sites, which contributes significantly to improving HER activity. The well‐designed Co‐BDC/MoS2 interface is vital for alkaline HER, as Co‐BDC makes it possible to speed up the sluggish water dissociation (rate‐limiting step for alkaline HER), and modified MoS2 is favorable for the subsequent hydrogen generation step. As expected, the resultant 2D Co‐BDC/MoS2 hybrid nanosheets demonstrate remarkable catalytic activity and good stability toward alkaline HER, outperforming those of bare Co‐BDC, MoS2, and almost all the previously reported MOF‐based electrocatalysts. 相似文献
11.
Zheng Yang Changsik Kim Kwang Young Lee Myeongjin Lee Samudrala Appalakondaiah Chang‐Ho Ra Kenji Watanabe Takashi Taniguchi Kyeongjae Cho Euyheon Hwang James Hone Won Jong Yoo 《Advanced materials (Deerfield Beach, Fla.)》2019,31(25)
Currently 2D crystals are being studied intensively for use in future nanoelectronics, as conventional semiconductor devices face challenges in high power consumption and short channel effects when scaled to the quantum limit. Toward this end, achieving barrier‐free contact to 2D semiconductors has emerged as a major roadblock. In conventional contacts to bulk metals, the 2D semiconductor Fermi levels become pinned inside the bandgap, deviating from the ideal Schottky–Mott rule and resulting in significant suppression of carrier transport in the device. Here, MoS2 polarity control is realized without extrinsic doping by employing a 1D elemental metal contact scheme. The use of high‐work‐function palladium (Pd) or gold (Au) enables a high‐quality p‐type dominant contact to intrinsic MoS2, realizing Fermi level depinning. Field‐effect transistors (FETs) with Pd edge contact and Au edge contact show high performance with the highest hole mobility reaching 330 and 432 cm2 V?1 s?1 at 300 K, respectively. The ideal Fermi level alignment allows creation of p‐ and n‐type FETs on the same intrinsic MoS2 flake using Pd and low‐work‐function molybdenum (Mo) contacts, respectively. This device acts as an efficient inverter, a basic building block for semiconductor integrated circuits, with gain reaching 15 at VD = 5 V. 相似文献
12.
Youngdong Yoo Zachary P. DeGregorio Yang Su Steven J. Koester James E. Johns 《Advanced materials (Deerfield Beach, Fla.)》2017,29(16)
The fabrication of in‐plane 2H‐1T′ MoTe2 homojunctions by the flux‐controlled, phase‐engineering of few‐layer MoTe2 from Mo nanoislands is reported. The phase of few‐layer MoTe2 is controlled by simply changing Te atomic flux controlled by the temperature of the reaction vessel. Few‐layer 2H MoTe2 is formed with high Te flux, while few‐layer 1T′ MoTe2 is obtained with low Te flux. With medium flux, few‐layer in‐plane 2H‐1T′ MoTe2 homojunctions are synthesized. As‐synthesized MoTe2 is characterized by Raman spectroscopy and X‐ray photoelectron spectroscopy. Kelvin probe force microscopy and Raman mapping confirm that in‐plane 2H‐1T′ MoTe2 homojunctions have abrupt interfaces between 2H and 1T′ MoTe2 domains, possessing a potential difference of about 100 mV. It is further shown that this method can be extended to create patterned metal–semiconductor junctions in MoTe2 in a two‐step lithographic synthesis. The flux‐controlled phase engineering method could be utilized for the large‐scale controlled fabrication of 2D metal–semiconductor junctions for next‐generation electronic and optoelectronic devices. 相似文献
13.
Synergetic Exfoliation and Lateral Size Engineering of MoS2 for Enhanced Photocatalytic Hydrogen Generation
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Lisha Yin Xiao Hai Kun Chang Fumihiko Ichihara Jinhua Ye 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(14)
Generally, exfoliation is an efficient strategy to create more edge site so as to expose more active sites on molybdenum disulphide (MoS2). However, the lateral sizes of the resultant MoS2 monolayers are relatively large (≈50–500 nm), which retain great potential to release more active sites. To further enhance the catalytic performance of MoS2, a facile cascade centrifugation‐assisted liquid phase exfoliation method is introduced here to fabricate monolayer enriched MoS2 nanosheets with nanoscale lateral sizes. The as‐prepared MoS2 revealed a high monolayer yield of 36% and small average lateral sizes ranging from 42 to 9 nm under gradient centrifugations, all exhibiting superior catalytic performances toward photocatalytic H2 generation. Particularly, the optimized monolayer MoS2 with an average lateral size of 9 nm achieves an apparent quantum efficiency as high as 77.2% on cadmium sulphide at 420 nm. This work demonstrates that the catalytic performances of MoS2 could be dramatically enhanced by synergistic exfoliation and lateral size engineering as a result of increased density of active sites and shortened charge diffusion distance, paving a new way for design and fabrication of transition‐metal dichalcogenides‐based materials in the application of hydrogen generation. 相似文献
14.
Gwang‐Hyeon Nam Qiyuan He Xingzhi Wang Yifu Yu Junze Chen Kang Zhang Zhenzhong Yang Dianyi Hu Zhuangchai Lai Bing Li Qihua Xiong Qing Zhang Lin Gu Hua Zhang 《Advanced materials (Deerfield Beach, Fla.)》2019,31(21)
Crystal phases play a key role in determining the physicochemical properties of a material. To date, many phases of transition metal dichalcogenides have been discovered, such as octahedral (1T), distorted octahedral (1T′), and trigonal prismatic (2H) phases. Among these, the 1T′ phase offers unique properties and advantages in various applications. Moreover, the 1T′ phase consists of unique zigzag chains of the transition metals, giving rise to interesting in‐plane anisotropic properties. Herein, the in‐plane optical and electrical anisotropies of metastable 1T′‐MoS2 layers are investigated by the angle‐resolved Raman spectroscopy and electrical measurements, respectively. The deconvolution of J1 and J2 peaks in the angle‐resolved Raman spectra is a key characteristic of high‐quality 1T′‐MoS2 crystal. Moreover, it is found that its electrocatalytic performance may be affected by the crystal orientation of anisotropic material due to the anisotropic charge transport. 相似文献
15.
Jin Bai Bangchuan Zhao Jiafeng Zhou Jianguo Si Zhitang Fang Kunzhen Li Hongyang Ma Jianming Dai Xuebin Zhu Yuping Sun 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(14)
1T phase MoS2 possesses higher conductivity than the 2H phase, which is a key parameter of electrochemical performance for lithium ion batteries (LIBs). Herein, a 1T‐MoS2/C hybrid is successfully synthesized through facile hydrothermal method with a proper glucose additive. The synthesized hybrid material is composed of smaller and fewer‐layer 1T‐MoS2 nanosheets covered by thin carbon layers with an enlarged interlayer spacing of 0.94 nm. When it is used as an anode material for LIBs, the enlarged interlayer spacing facilitates rapid intercalating and deintercalating of lithium ions and accommodates volume change during cycling. The high intrinsic conductivity of 1T‐MoS2 also contributes to a faster transfer of lithium ions and electrons. Moreover, much smaller and fewer‐layer nanosheets can shorten the diffusion path of lithium ions and accelerate reaction kinetics, leading to an improved electrochemical performance. It delivers a high initial capacity of 920.6 mAh g?1 at 1 A g?1 and the capacity can maintain 870 mAh g?1 even after 300 cycles, showing a superior cycling stability. The electrode presents a high rate performance as well with a reversible capacity of 600 mAh g?1 at 10 A g?1. These results show that the 1T‐MoS2/C hybrid shows potential for use in high‐performance lithium‐ion batteries. 相似文献
16.
Panpan Zhang Sheng Yang Roberto Pineda‐Gmez Bergoi Ibarlucea Ji Ma Martin R. Lohe Teuku Fawzul Akbar Larysa Baraban Gianaurelio Cuniberti Xinliang Feng 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(23)
2D molybdenum disulfide (MoS2) gives a new inspiration for the field of nanoelectronics, photovoltaics, and sensorics. However, the most common processing technology, e.g., liquid‐phase based scalable exfoliation used for device fabrication, leads to the number of shortcomings that impede their large area production and integration. Major challenges are associated with the small size and low concentration of MoS2 flakes, as well as insufficient control over their physical properties, e.g., internal heterogeneity of the metallic and semiconducting phases. Here it is demonstrated that large semiconducting MoS2 sheets (with dimensions up to 50 µm) can be obtained by a facile cathodic exfoliation approach in nonaqueous electrolyte. The synthetic process avoids surface oxidation thus preserving the MoS2 sheets with intact crystalline structure. It is further demonstrated at the proof‐of‐concept level, a solution‐processed large area (60 × 60 µm) flexible Ebola biosensor, based on a MoS2 thin film (6 µm thickness) fabricated via restacking of the multiple flakes on the polyimide substrate. The experimental results reveal a low detection limit (in femtomolar–picomolar range) of the fabricated sensor devices. The presented exfoliation method opens up new opportunities for fabrication of large arrays of multifunctional biomedical devices based on novel 2D materials. 相似文献
17.
Jing Zhang Jingjie Wu Hua Guo Weibing Chen Jiangtan Yuan Ulises Martinez Gautam Gupta Aditya Mohite Pulickel M. Ajayan Jun Lou 《Advanced materials (Deerfield Beach, Fla.)》2017,29(42)
Here, the hydrogen evolution reaction (HER) activities at the edge and basal‐plane sites of monolayer molybdenum disulfide (MoS2) synthesized by chemical vapor deposition (CVD) are studied using a local probe method enabled by selected‐area lithography. Reaction windows are opened by e‐beam lithography at sites of interest on poly(methyl methacrylate) (PMMA)‐covered monolayer MoS2 triangles. The HER properties of MoS2 edge sites are obtained by subtraction of the activity of the basal‐plane sites from results containing both basal‐plane and edge sites. The catalytic performances in terms of turnover frequencies (TOFs) are calculated based on the estimated number of active sites on the selected areas. The TOFs follow a descending order of 3.8 ± 1.6, 1.6 ± 1.2, 0.008 ± 0.002, and 1.9 ± 0.8 × 10?4 s?1, found for 1T′‐, 2H‐MoS2 edges, and 1T′‐, 2H‐MoS2 basal planes, respectively. Edge sites of both 2H‐ and 1T′‐MoS2 are proved to have comparable activities to platinum (≈1–10 s?1). When fitted into the HER volcano plot, the MoS2 active sites follow a trend distinct from conventional metals, implying a possible difference in the reaction mechanism between transition‐metal dichalcogenides (TMDs) and metal catalysts. 相似文献
18.
Qingqing Ke Xiao Zhang Wenjie Zang Abdelnaby M. Elshahawy Yating Hu Qiyuan He Stephen J. Pennycook Yongqing Cai John Wang 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(21)
Transition metal dichalcogenides exhibit several different phases (e.g., semiconducting 2H, metallic 1T, 1T′) arising from the collective and sluggish atomic displacements rooted in the charge‐lattice interaction. The coexistence of multiphase in a single sheet enables ubiquitous heterophase and inhomogeneous charge distribution. Herein, by combining the first‐principles calculations and experimental investigations, a strong charge transfer ability at the heterophase boundary of molybdenum disulfide (MoS2) assembled together with graphene is reported. By modulating the phase composition in MoS2, the performance of the nanohybrid for energy storage can be modulated, whereby remarkable gravimetric and volumetric capacitances of 272 F g?1 and 685 F cm?3 are demonstrated. As a proof of concept for energy application, a flexible solid‐state asymmetric supercapacitor is constructed with the MoS2‐graphene heterolayers, which shows superb energy and power densities (46.3 mWh cm?3 and 3.013 W cm?3, respectively). The present work demonstrates a new pathway for efficient charge flow and application in energy storage by engineering the phase boundary and interface in 2D materials of transition metal dichalcogenides. 相似文献
19.
Structural Phase Transition Effect on Resistive Switching Behavior of MoS2‐Polyvinylpyrrolidone Nanocomposites Films for Flexible Memory Devices
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Peng Zhang Cunxu Gao Benhua Xu Lin Qi Changjun Jiang Meizhen Gao Desheng Xue 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(15):2077-2084
The 2H phase and 1T phase coexisting in the same molybdenum disulfide (MoS2) nanosheets can influence the electronic properties of the materials. The 1T phase of MoS2 is introduced into the 2H‐MoS2 nanosheets by two‐step hydrothermal synthetic methods. Two types of nonvolatile memory effects, namely write‐once read‐many times memory and rewritable memory effect, are observed in the flexible memory devices with the configuration of Al/1T@2H‐MoS2‐polyvinylpyrrolidone (PVP)/indium tin oxide (ITO)/polyethylene terephthalate (PET) and Al/2H‐MoS2‐PVP/ITO/PET, respectively. It is observed that structural phase transition in MoS2 nanosheets plays an important role on the resistive switching behaviors of the MoS2‐based device. It is hoped that our results can offer a general route for the preparation of various promising nanocomposites based on 2D nanosheets of layered transition metal dichalcogenides for fabricating the high performance and flexible nonvolatile memory devices through regulating the phase structure in the 2D nanosheets. 相似文献
20.
Zhi‐Wen Gao Mengjie Liu Weiran Zheng Xiandi Zhang Lawrence Yoon Suk Lee 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(44)
With excellent performance in the hydrogen evolution reaction (HER), molybdenum disulfide (MoS2) is considered a promising nonprecious candidate to substitute Pt‐based catalysts. Herein, pulsed laser irradiation in liquid is used to realize one‐step exfoliation of bulk 2H‐MoS2 to ultrastable few‐layer MoS2 nanosheets. Such prepared MoS2 nanosheets are rich in S vacancies and metallic 1T phase, which significantly contribute to the boosted catalytic HER activity. Protic solvents play a pivotal role in the production of S vacancies and 2H‐to‐1T phase transition under laser irradiation. MoS2 exfoliated in an optimal solvent of formic acid exhibits outstanding HER activity with an overpotential of 180 mV at 10 mA cm?2 and Tafel slope of 54 mV dec?1. 相似文献