23 results on '"Junjie Li"'
Search Results
2. Sn-Doped Bi2O3 nanosheets for highly efficient electrochemical CO2 reduction toward formate production
- Author
-
Deren Yang, Junjie Li, Zihan Leng, Xiao Li, Xingqiao Wu, Hui Zhang, Jingbo Huang, Ningkang Qian, and Liang Ji
- Subjects
chemistry.chemical_compound ,Materials science ,chemistry ,Inorganic chemistry ,General Materials Science ,Formate ,Selectivity ,Electrocatalyst ,Electrochemistry ,Faraday efficiency ,Catalysis ,Anode ,Nanosheet - Abstract
Electrocatalytic CO2 reduction to formate is considered as a perfect route for efficient conversion of the greenhouse gas CO2 to value-added chemicals. However, it still remains a huge challenge to design a catalyst with both high catalytic activity and selectivity for target products. Here we report a unique Sn-doped Bi2O3 nanosheet (NS) electrocatalyst with different atomic percentages of Sn (1.2, 2.5, and 3.8%) prepared by a simple solvothermal method for highly efficient electrochemical reduction of CO2 to formate. Of them, the 2.5% Sn-doped Bi2O3 NSs exhibited the highest faradaic efficiency (FE) of 93.4% with a current density of 24.3 mA cm-2 for formate at -0.97 V in the H-cell and a maximum current density of nearly 50 mA cm-2 was achieved at -1.27 V. The formate FE is stable maintained at over 90% in a wide potential range from -0.87 V to -1.17 V. Electrochemical and density functional theory (DFT) analyses of undoped and Sn doped Bi2O3 NSs indicated that the strong synergistic effect between Sn and Bi is responsible for the enhancement in the adsorption capacity of the OCHO* intermediate, and thus the activity for formate production. In addition, we coupled 2.5% Sn-doped Bi2O3 NSs with a dimensionally stable anode (DSA) to realize battery-driven highly active CO2RR and OER with decent activity and efficiency.
- Published
- 2021
3. Realization of a near-infrared active Fano-resonant asymmetric metasurface by precisely controlling the phase transition of Ge2Sb2Te5
- Author
-
Ce Li, Wei Zhu, Shi Yan, Ruisheng Yang, Changzhi Gu, Fuli Zhang, Quanhong Fu, Junjie Li, and Yuancheng Fan
- Subjects
Phase transition ,Materials science ,business.industry ,Physics::Optics ,Fano resonance ,Heterojunction ,02 engineering and technology ,Fano plane ,021001 nanoscience & nanotechnology ,01 natural sciences ,Resonator ,Modulation ,0103 physical sciences ,Optoelectronics ,General Materials Science ,Photonics ,010306 general physics ,0210 nano-technology ,business ,Realization (systems) - Abstract
A metasurface is one of the most effectual platforms for the manipulation of complex optical fields. One of the current challenges in the field is to develop active or reconfigurable functionalities to extend its operation band which is limited by its intrinsic resonant nature. Here we demonstrate a kind of active Fano-resonant asymmetric metasurface in the near-infrared (NIR) region with heterostructures made of a layer of asymmetric split-ring resonators and a thin layer of phase-change material (PCM). In the asymmetric metasurface, significant tunability in the frequency, Q-factor and strength of the Fano resonance are all achieved by precisely controlling the phase transition of the contained PCM Ge2Sb2Te5 (GST), together with changing the geometric asymmetry of the split-ring resonators. Moreover, we provide a complete transition process of the optical properties for GST and an optimized modulation on the active Fano-resonant metasurface. Our approach to dynamically control a Fano-resonant metasurface paves the way to realizing various active photonic meta-devices involving PCM.
- Published
- 2020
4. Engineering high-robustness DNA molecular circuits by utilizing nucleases
- Author
-
Lida Xu, Junjie Li, Xin Su, Shengnan Fu, Yingnan Deng, Changyuan Yu, and Na Li
- Subjects
Exonucleases ,Exonuclease ,Materials science ,Computation ,Kinetics ,010402 general chemistry ,01 natural sciences ,Computers, Molecular ,03 medical and health sciences ,chemistry.chemical_compound ,DNA nanotechnology ,Hardware_INTEGRATEDCIRCUITS ,General Materials Science ,030304 developmental biology ,Leakage (electronics) ,Electronic circuit ,0303 health sciences ,biology ,Viral Proteases ,DNA ,Bacteriophage lambda ,0104 chemical sciences ,chemistry ,Cascade ,biology.protein ,Biological system - Abstract
Toehold-mediated strand displacement (TMSD) as an important player in DNA nanotechnology has been widely utilized for engineering non-enzymatic molecular circuits. However, these circuits suffer from uncontrollable leakage and unsatisfactory response speed. We utilized site-specific and sequence-independent nucleases to engineer high- robustness DNA molecular circuits. First, we found that the kinetics of the APE1-catalyzed reaction is highly dependent on substrate stability, allowing for the elimination of asymptotic leakage of DNA split circuits. Second, we obtained strict substrate preference of λ exonuclease (λexo) by optimizing the reaction conditions. Robust single-layer and cascade gates with leak resistance were established by using λ exo. Owing to the remarkably fast kinetics of these nucleases, all the circuits yield a high speed of computation. Compared to TMSD-based approaches, nuclease-powered circuits render advanced features such as leakage resistance, hundreds of times higher speed, and simplified structures, representing a class of promising artificial molecule systems.
- Published
- 2020
5. Sn-Doped Bi
- Author
-
Xiao, Li, Xingqiao, Wu, Junjie, Li, Jingbo, Huang, Liang, Ji, Zihan, Leng, Ningkang, Qian, Deren, Yang, and Hui, Zhang
- Abstract
Electrocatalytic CO
- Published
- 2021
6. A photo-inducible protein–inorganic nanoparticle assembly for active targeted tumour theranostics
- Author
-
Aarushi Iris, Jinbing Xie, Junjie Li, Yining Qiu, Ling Mei, Yuxiang Sun, Gang Han, Kai Huang, and Baoliang Ma
- Subjects
Male ,Paclitaxel ,Theranostic Nanomedicine ,Cell Survival ,Ultraviolet Rays ,Transplantation, Heterologous ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,Microscopy, Atomic Force ,010402 general chemistry ,01 natural sciences ,Polyethylene Glycols ,Mice ,Cell Line, Tumor ,Neoplasms ,Quantum Dots ,Animals ,Humans ,Tissue Distribution ,General Materials Science ,chemistry.chemical_classification ,Drug Carriers ,Mice, Inbred BALB C ,Chemistry ,Polymer ,021001 nanoscience & nanotechnology ,Small molecule ,0104 chemical sciences ,Transplantation ,Drug delivery ,Nanoparticles ,Muramidase ,Nanocarriers ,0210 nano-technology ,Oligopeptides ,Biosensor - Abstract
The assembly of protein-inorganic nanoparticles is an important yet challenging approach that is utilized to develop functional materials in numerous areas, such as bio-catalysis, drug delivery, and biosensing. In this study, we report on a facile, photo-inducible self-assembly method to generate protein-inorganic hybrid nanoplatforms. More specifically, photo-treated disulfide bond rich proteins of lysozyme (LYS) were able to be used as host materials in order to encapsulate nanoparticles (i.e., as-synthesized hydrophobic NIR quantum dots (QDs)) and anti-cancer small molecule drugs (i.e., paclitaxel (PTX)), constructing functional theranostic protein-inorganic hybrid nanoparticles. The modification of the functional polymer of cRGD-PEG contributes to the active tumour targeting characteristic of this protein-inorganic nanocarrier. This novel PTX loaded protein-inorganic hybrid nanoplatform showed high tumour homing accumulation as well as effective tumour inhibition. We believe that this general approach represents a new direction for the development of a photo-induced assembly of protein-inorganic nanoparticles towards versatile applications in both materials science and biomedical fields.
- Published
- 2019
7. Intermetallic Pd3Pb ultrathin nanoplate-constructed flowers with low-coordinated edge sites boost oxygen reduction performance
- Author
-
Yang Ou, Mingxi Gao, Junjie Li, Lei Li, Deren Yang, Xingqiao Wu, Yi Jiang, Sai Luo, Hui Zhang, and Xiaofang Yang
- Subjects
Nanostructure ,Materials science ,Intermetallic ,02 engineering and technology ,Edge (geometry) ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Durability ,Oxygen reduction ,0104 chemical sciences ,Catalysis ,Chemical engineering ,Phase (matter) ,Reversible hydrogen electrode ,General Materials Science ,0210 nano-technology - Abstract
Although tremendous efforts have been devoted to exploring non-Pt based electrocatalysts toward the oxygen reduction reaction (ORR), achievements in both catalytic activity and durability are still far from satisfactory. Here, we report a facile approach for the synthesis of intermetallic Pd3Pb ultrathin nanoplate-constructed flowers. Such highly opened hierarchical nanostructures with an ordered phase and low-coordinated edge sites exhibited a substantially enhanced activity toward the ORR. Especially, the intermetallic Pd3Pb nanoflowers achieved a record-breaking mass activity (1.14 mA μgPd−1) in an alkaline solution at 0.9 V vs. a reversible hydrogen electrode among the reported Pd-based ORR electrocatalysts to date, which was 1.8, 3.9 and 11.4 times higher than those of intermetallic Pd3Pb nanocubes, Pd3Pb dendrites and commercial Pt/C, respectively. More importantly, the intermetallic Pd3Pb nanoflowers also showed a higher durability with only 23.7% loss in mass activity after 10 000 cycles compared to the commercial Pt/C (35% loss in mass activity) due to their chemically stable intermetallic structures.
- Published
- 2019
8. Biodegradable MnO2 nanosheet mediated hybridization chain reaction for imaging of human apurinic/apyrimidinic endonuclease 1 activity in living cells
- Author
-
Guangli Li, Junjie Li, and Qing Li
- Subjects
In situ ,biology ,Chemistry ,Confocal ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Endocytosis ,01 natural sciences ,0104 chemical sciences ,Nucleic acid thermodynamics ,Endonuclease ,Biochemistry ,biology.protein ,General Materials Science ,AP site ,0210 nano-technology ,Intracellular ,Nanosheet - Abstract
A highly sensitive enzyme-free amplification assay for the detection of apurinic/apyrimidinic endonuclease 1 activity was developed. By incorporating biodegradable MnO2 nanosheets, in situ light up intracellular APE 1 activity was achieved.
- Published
- 2019
9. Independent tuning of bright and dark meta-atoms with phase change materials on EIT metasurfaces
- Author
-
Ce Li, Wei Zhu, Zhe Liu, Junjie Li, Shuo Du, Changzhi Gu, Sha Hu, and Ruhao Pan
- Subjects
Electromagnetic field ,Physics ,business.industry ,Electromagnetically induced transparency ,Physics::Optics ,02 engineering and technology ,STRIPS ,021001 nanoscience & nanotechnology ,Slow light ,01 natural sciences ,Spectral line ,law.invention ,Phase change ,law ,0103 physical sciences ,Optoelectronics ,General Materials Science ,010306 general physics ,0210 nano-technology ,business ,Lithography - Abstract
The realization of tunable metasurfaces is of fundamental importance for boosting the electromagnetic field control ability. Especially, it is important to put forward new modulation methods to further understand their underlying modulation mechanism and expand their application range. In this paper, tunable electromagnetically induced transparency (EIT) metasurfaces based on the phase change material Ge2Sb2Te5 (GST) are proposed and experimentally demonstrated. Different from previous modulation methods of directly introducing the GST film below the metasurfaces, here a two-step lithography method is introduced to combine independent GST strips with bright and dark meta-atoms in the EIT structures, respectively, achieving the independent modulation of the EIT-like spectra. In addition, by applying temporal coupled-mode theory (TCMT), the EIT-like spectra with different GST crystallization levels were analysed and the corresponding characteristic parameters were determined simultaneously. These fitting results reveal that GST strips can modulate the resonances of the bright and dark meta-atoms independently by shifting the resonant frequency and increasing the decay rate, which in turn result in the different modulation features of the EIT-like spectra. This method improves the degree of freedom of active modulation and provides a new route for tunable slow light devices.
- Published
- 2020
10. Realization of a near-infrared active Fano-resonant asymmetric metasurface by precisely controlling the phase transition of Ge
- Author
-
Wei, Zhu, Yuancheng, Fan, Ce, Li, Ruisheng, Yang, Shi, Yan, Quanhong, Fu, Fuli, Zhang, Changzhi, Gu, and Junjie, Li
- Abstract
A metasurface is one of the most effectual platforms for the manipulation of complex optical fields. One of the current challenges in the field is to develop active or reconfigurable functionalities to extend its operation band which is limited by its intrinsic resonant nature. Here we demonstrate a kind of active Fano-resonant asymmetric metasurface in the near-infrared (NIR) region with heterostructures made of a layer of asymmetric split-ring resonators and a thin layer of phase-change material (PCM). In the asymmetric metasurface, significant tunability in the frequency, Q-factor and strength of the Fano resonance are all achieved by precisely controlling the phase transition of the contained PCM Ge
- Published
- 2020
11. Biodegradable MnO
- Author
-
Guangli, Li, Junjie, Li, and Qing, Li
- Subjects
Microscopy, Confocal ,Manganese Compounds ,DNA-(Apurinic or Apyrimidinic Site) Lyase ,Humans ,Nucleic Acid Hybridization ,Oxides ,DNA ,DNA Probes ,Glutathione ,Nucleic Acid Amplification Techniques ,Endocytosis ,HeLa Cells ,Nanostructures - Abstract
A highly sensitive enzyme-free amplification assay for the detection of apurinic/apyrimidinic endonuclease 1 activity was developed. By incorporating biodegradable MnO
- Published
- 2019
12. Strain-induced Stranski–Krastanov growth of Pd@Pt core–shell hexapods and octapods as electrocatalysts for methanol oxidation
- Author
-
Jianbo Wu, Junjie Li, Deren Yang, Yucong Yan, Jingbo Huang, Yalin Xiong, Yanling Ma, and Hui Zhang
- Subjects
Nanostructure ,Chemistry ,Nanotechnology ,02 engineering and technology ,Island growth ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Epitaxy ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Stranski–Krastanov growth ,Nanocrystal ,Chemical engineering ,Oleylamine ,General Materials Science ,0210 nano-technology ,Bimetallic strip - Abstract
Bimetallic nanocrystals with a branched shape have received great interest as catalysts due to their unique structures and fascinating properties. However, the conventional synthetic approaches based on the island growth mode often lead to the dendritic nanostructures with inhomogeneous and uncontrolled branches. Here precise control over the number of branches has been realized in the deposition of Pt on Pd seeds through the Stranski–Krastanov growth mechanism. Based on such a growth mode, Pd@Pt core–shell hexapods and octapods have been generated by a seeded growth with Pd octahedra and cubes as the seeds, respectively. We found that Pt atoms are initially deposited on the side faces of Pd seeds through a layer-by-layer epitaxial growth in the presence of oleylamine (OAm), leading to a local strain focused at their corners. These strain-concentrated sites promote the subsequent island growth of Pt atoms at the corners of the Pd seeds, resulting in the Pd@Pt core–shell hexapods or octapods. Both the Pd@Pt core–shell hexapods and octapods exhibit the substantially enhanced catalytic properties in terms of activity and stability towards a methanol oxidation reaction (MOR) relative to the commercial Pt/C. Specifically, the Pd@Pt core–shell hexapods show the highest specific (1.97 mA cm−2) activity and mass activity (0.52 mA μgPt−1) for the MOR, which are 5.8 and 2.6 times higher than those of the commercial Pt/C, respectively. This enhancement can probably be attributed to their unique structures and the synergistic effect between Pt and Pd.
- Published
- 2017
13. Intermetallic Pd
- Author
-
Sai, Luo, Yang, Ou, Lei, Li, Junjie, Li, Xingqiao, Wu, Yi, Jiang, Mingxi, Gao, Xiaofang, Yang, Hui, Zhang, and Deren, Yang
- Abstract
Although tremendous efforts have been devoted to exploring non-Pt based electrocatalysts toward the oxygen reduction reaction (ORR), achievements in both catalytic activity and durability are still far from satisfactory. Here, we report a facile approach for the synthesis of intermetallic Pd3Pb ultrathin nanoplate-constructed flowers. Such highly opened hierarchical nanostructures with an ordered phase and low-coordinated edge sites exhibited a substantially enhanced activity toward the ORR. Especially, the intermetallic Pd3Pb nanoflowers achieved a record-breaking mass activity (1.14 mA μgPd-1) in an alkaline solution at 0.9 V vs. a reversible hydrogen electrode among the reported Pd-based ORR electrocatalysts to date, which was 1.8, 3.9 and 11.4 times higher than those of intermetallic Pd3Pb nanocubes, Pd3Pb dendrites and commercial Pt/C, respectively. More importantly, the intermetallic Pd3Pb nanoflowers also showed a higher durability with only 23.7% loss in mass activity after 10 000 cycles compared to the commercial Pt/C (35% loss in mass activity) due to their chemically stable intermetallic structures.
- Published
- 2019
14. Diameter-optimized high-order waveguide nanorods for fluorescence enhancement applied in ultrasensitive bioassays
- Author
-
Flemming Besenbacher, Baosheng Du, Krishna C. Balram, Chengchun Tang, Henkjan Gersen, Wenwu Cao, Bin Yang, Miao Yu, Junjie Li, Ye Sun, Changzhi Gu, Hong Zhang, Zhao Dan, and Dengfeng Yu
- Subjects
Waveguide (electromagnetism) ,Materials science ,02 engineering and technology ,010402 general chemistry ,Bristol Quantum Information Institute ,01 natural sciences ,Sensing platforms ,QETLabs ,NANORODS ,Limit of Detection ,Neoplasms ,Humans ,General Materials Science ,High order ,Biochip ,Fluorescent Dyes ,Detection limit ,Hexagonal prism ,Immunoassay ,Nanotubes ,BIOASSAYS ,business.industry ,Rhodamines ,fluorescence enhancement ,waveguides ,021001 nanoscience & nanotechnology ,Fluorescence ,0104 chemical sciences ,Carcinoembryonic Antigen ,ZnO ,Optoelectronics ,Nanorod ,Biological Assay ,fluorescence ,Zinc Oxide ,0210 nano-technology ,business ,Biosensor ,Biomarkers - Abstract
Development of fluorescence enhancement (FE) platforms based on ZnO nanorods (NRs) has sparked considerable interest, thanks to their well-demonstrated potential in chemical and biological detection. Among the multiple factors determining the FE performance, high-order waveguide modes are specifically promising in boosting the sensitivity and realizing selective detection. However, quantitative experimental studies on the influence of the NR diameter, substrate, and surrounding medium, on the waveguide-based FE properties remain lacking. In this work, we have designed and fabricated a FE platform based on patterned and well-defined arrays of vertical, hexagonal prism ZnO NRs with six distinct diameters. Both direct experimental evidence and theoretical simulations demonstrate that high-order waveguide modes play a crucial role in FE, and are strongly dependent on the NR diameter, substrate, and surrounding medium. Using the optimized FE platform, a significant limit of detection (LOD) of 10-16 mol L-1 for Rhodamine-6G probe detection is achieved. Especially, a LOD as low as 10-14 g mL-1 is demonstrated for a prototype biomarker of carcinoembryonic antigen, which is improved by one order compared with the best LOD ever reported using fluorescence-based detection. This work provides an efficient path to design waveguiding NRs-based biochips for ultrasensitive and highly-selective biosensing.
- Published
- 2019
15. In-memory direct processing based on nanoscale perpendicular magnetic tunnel junctions
- Author
-
Wenlong Cai, Kaihua Cao, Yizheng Liu, Xiaobin He, Hushan Cui, Chao Zhao, Weisheng Zhao, Jiaqi Wei, Junjie Li, and Huisong Li
- Subjects
010302 applied physics ,Computer science ,business.industry ,Spin-transfer torque ,Electrical engineering ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Bottleneck ,Power (physics) ,Stateful firewall ,Logic gate ,0103 physical sciences ,Perpendicular ,General Materials Science ,Hardware_ARITHMETICANDLOGICSTRUCTURES ,0210 nano-technology ,Boolean function ,business ,Energy (signal processing) - Abstract
Perpendicular magnetic tunnel junctions (p-MTJs) provide advantages such as infinite endurance, high thermal stability, and fast and low-power switching. They are considered as a promising non-volatile memory device to build non-von Neumann computing paradigms and definitively overcome the power bottleneck. Numerous design proposals have been made for p-MTJ logic, but a few physical realizations have been reported. In this paper, we present the experimental implementation of universal stateful logic gates such as “OR”, “AND”, and material implication (“IMP”) by connecting two nanoscale p-MTJs in parallel. Owing to the voltage dependence of switching probability for the spin transfer torque mechanism, the same structure can be reconfigured to different logic gates with only electrical signals. One single-cycle operation is thus required for all the basic Boolean functions. Such in-memory direct processing has great potential to meet some key requirements such as a high energy/areal efficiency and high speed for future computing hardware.
- Published
- 2018
16. Nanocracking and metallization doubly defined large-scale 3D plasmonic sub-10 nm-gap arrays as extremely sensitive SERS substrates
- Author
-
Yunlong Li, Yewang Su, Baogang Quan, Yang Yang, Ruhao Pan, Shuang Li, Zhe Liu, Yujin Wang, Changzhi Gu, and Junjie Li
- Subjects
Materials science ,business.industry ,02 engineering and technology ,Substrate (electronics) ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Rhodamine 6G ,chemistry.chemical_compound ,symbols.namesake ,chemistry ,symbols ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business ,Raman spectroscopy ,Nanoscopic scale ,Local field ,Plasmon ,Raman scattering ,Deposition (law) - Abstract
Considering the technological difficulties in the existing approaches to form nanoscale gaps, a convenient method to fabricate three-dimensional (3D) sub-10 nm Ag/SiNx gap arrays has been demonstrated in this study, controlled by a combination of stress-induced nanocracking of a SiNx nanobridge and Ag nanofilm deposition. This scalable 3D plasmonic nanogap is specially suspended above a substrate, having a tunable nanogap width and large height-to-width ratio to form a nanocavity underneath. As a surface-enhanced Raman scattering (SERS) substrate, the 3D Ag/SiNx nanogap shows a large Raman enhancement factor of ∼108 and extremely high sensitivity for the detection of Rhodamine 6G (R6G) molecules, even down to 10-16 M, indicating an extraordinary capability for single-molecule detection. Further, we verified that the Fabry-Perot resonance occurred in the deep SiNx nanocavity under the Ag nanogap and contributed prominently to a tremendous enhancement of the local field in the Ag-nanogap zone and hence ultrasensitive SERS detection. This method circumvents the technological limitations to fabricate a sub-10 nm metal nanogap with unique features for wide applications in important scientific and technological areas.
- Published
- 2018
17. A dewetting route to grow heterostructured nanoparticles based on thin film heterojunctions
- Author
-
Qiang Li, Zhongchang Wang, Junjie Li, Deqiang Yin, Chunlin Chen, and Sumei Huang
- Subjects
Metal ,Materials science ,Annealing (metallurgy) ,visual_art ,visual_art.visual_art_medium ,Nanoparticle ,General Materials Science ,Nanotechnology ,Heterojunction ,Dumbbell ,Dewetting ,Thin film ,Wetting layer - Abstract
Heterostructured nanoparticles have received considerable attention for their various applications due to their unique and tunable functionalities with respect to their individual bulk constituents. However, the current wet chemical synthesis of multicomponent heterostructured nanoparticles is rather complicated. Here, we report a simple and quick method to fabricate Co-Au dumbbell arrays by dewetting Co/Au heterojunctions on a Si substrate and demonstrate that the Co-Au dumbbells vary in size from 2 to 28 nm. We further show by chemical mapping that Co bells are covered by a pseudomorphic Au wetting layer of ∼4 Å, preventing the bells from oxidation. By controlling the thickness of metal heterojunctions and the annealing time, the morphology of the Co-Au nanoparticle is found to be transformed from the dumbbell to the core shell. This facile route is demonstrated to be useful for fabricating other metal-metal and metal-oxide heterostructures and hence holds technological promise for functional applications.
- Published
- 2015
18. Side-by-side observation of the interfacial improvement of vertical graphene-coated silicon nanocone anodes for lithium-ion batteries by patterning technology
- Author
-
Liquan Chen, Hong Li, Bonan Liu, Baogang Quan, Chao Wang, Changzhi Gu, Chu Geng, Hao Lu, Junjie Li, and Fei Luo
- Subjects
Nanostructure ,Materials science ,Silicon ,Graphene ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Anode ,law.invention ,Coating ,chemistry ,law ,Electrode ,engineering ,General Materials Science ,0210 nano-technology ,Layer (electronics) ,Faraday efficiency - Abstract
We report that vertical graphene coating can greatly improve the electrochemical performance and the interfacial stability of silicon nanocone (SNC) anodes for lithium-ion batteries. The coating patterning technology is innovatively employed for side-by-side demonstration of the exclusive influences of graphene coating on the solid-electrolyte interphase (SEI) formation and the structural stability of the SNC electrode. The silicon nanocone-graphene (SNC-G) electrode achieves a longer cycle life (1715 cycles), higher Coulombic efficiency (average 98.2%), better rate capability, and lower electrode polarization than the SNC electrode. The patterning of the graphene coating provides a much direct and convincing morphological comparison between the SNC-G structure and the SNC structure, showing clearly that the SNC-G area maintains a thin SEI layer and stable nanostructure after cycling, while the SNC area is gradually damaged and covered with a thick SEI layer after 100 cycles. Our results clearly indicate the improved electrochemical performance and interfacial stability attributed to the vertical graphene coating, and the as-proposed patterning technology also paves a new way for comparative research on coating materials for lithium-ion batteries.
- Published
- 2017
19. Atomic-layer-deposited ultrafine MoS
- Author
-
Dehua, Xiong, Qingqing, Zhang, Wei, Li, Junjie, Li, Xiuli, Fu, M F, Cerqueira, Pedro, Alpuim, and Lifeng, Liu
- Abstract
Ultrafine molybdenum sulfide (MoS
- Published
- 2017
20. Covalent bonding of YIGSR and RGD to PEDOT/PSS/MWCNT-COOH composite material to improve the neural interface
- Author
-
Xiao-Xia Jiang, Junjie Li, Changyong Wang, Hong-Ji Sun, Xiao-Bo Zhao, Yiran Lang, Rong-Yu Tang, Kun Wang, and Qiuxia Lin
- Subjects
Neurons ,Materials science ,Biocompatibility ,Nanotubes, Carbon ,Nanowires ,Polymers ,Composite number ,Coating materials ,Carbon nanotube ,Electrochemistry ,Bridged Bicyclo Compounds, Heterocyclic ,PC12 Cells ,law.invention ,Rats ,PEDOT:PSS ,law ,Covalent bond ,Electrode ,Materials Testing ,Animals ,General Materials Science ,Composite material ,Oligopeptides - Abstract
The development of coating materials for neural interfaces has been a pursued to improve the electrical, mechanical and biological performances. For these goals, a bioactive coating was developed in this work featuring a poly(3,4-ethylenedioxythiophene) (PEDOT)/carbon nanotube (CNT) composite and covalently bonded YIGSR and RGD. Its biological effect and electrical characteristics were assessed in vivo on microwire arrays (MWA). The coated electrodes exhibited a significantly higher charge storage capacity (CSC) and lower electrochemical impedance at 1 kHz which are desired to improve the stimulating and recording performances, respectively. Acute neural recording experiments revealed that coated MWA possess a higher signal/noise ratio capturing spikes undetected by uncoated electrodes. Moreover, coated MWA possessed more active sites and single units, and the noise floor of coated electrodes was lower than that of uncoated electrodes. There is little information in the literature concerning the chronic performance of bioactively modified neural interfaces in vivo. Therefore in this work, chronic in vivo tests were conducted and the PEDOT/PSS/MWCNT-polypeptide coated arrays exhibited excellent performances with the highest mean maximal amplitude from day 4 to day 12 during which the acute response severely compromised the performance of the electrodes. In brief, we developed a simple method of covalently bonding YIGSR and RGD to a PEDOT/PSS/MWCNT-COOH composite improving both the biocompatibility and electrical performance of the neural interface. Our findings suggest that YIGSR and RGD modified PEDOT/PSS/MWCNT is a promising bioactivated composite coating for neural recording and stimulating.
- Published
- 2015
21. Thick solid electrolyte interphases grown on silicon nanocone anodes during slow cycling and their negative effects on the performance of Li-ion batteries
- Author
-
Chu Geng, Fei Luo, Bonan Liu, Liquan Chen, Jieyun Zheng, Changzhi Gu, Xiaoxiang Xia, Junjie Li, and Hong Li
- Subjects
Materials science ,Silicon ,Passivation ,chemistry.chemical_element ,Nanotechnology ,Electrolyte ,Lithium battery ,Half-cell ,Anode ,chemistry ,Electrode ,General Materials Science ,Wafer ,Composite material - Abstract
Thickness, homogeneity and coverage of the surface passivation layer on Si anodes for Li-ion batteries have decisive influences on their cyclic performance and coulombic efficiency, but related information is difficult to obtain, especially during cycling. In this work, a well-defined silicon nanocone (SNC) on silicon wafer sample has been fabricated as a model electrode in lithium ion batteries to investigate the growth of surface species on the SNC electrode during cycling using ex situ scanning electronic microscopy. It is observed that an extra 5 μm thick layer covers the top of the SNCs after 25 cycles at 0.1 C. This top layer has been proven to be a solid electrolyte interphase (SEI) layer by designing a solid lithium battery. It is noticed that the SEI layer is much thinner at a high rate of 1 C. The cyclic performance of the SNCs at 1 C looks much better than that of the same electrode at 0.1 C in the half cell. Our findings clearly demonstrate that the formation of the thick SEI on the naked nanostructured Si anode during low rate cycling is a serious problem for practical applications. An in depth understanding of this problem may provide valuable guidance in designing Si-based anode materials.
- Published
- 2015
22. CVD synthesis of large-area, highly crystalline MoSe2atomic layers on diverse substrates and application to photodetectors
- Author
-
Zhu Dandan, Lei Wang, Junjie Li, Jing Xia, Changzhi Gu, Huang Ben, Meng Wang, Xiang-Min Meng, Xing Huang, and Lingzhi Liu
- Subjects
symbols.namesake ,Photoluminescence ,Materials science ,Transmission electron microscopy ,Monolayer ,symbols ,Analytical chemistry ,General Materials Science ,Heterojunction ,Direct and indirect band gaps ,Chemical vapor deposition ,Raman spectroscopy ,Spectroscopy - Abstract
Synthesis of large-area atomically thin transition metal dichalcogenides (TMDs) on diverse substrates is of central importance for large-scale fabrication of flexible devices and heterojunction-based devices. In this work, we successfully synthesized a large area of highly crystalline MoSe2 atomic layers on SiO2/Si, mica and Si substrates by using a simple atmospheric pressure chemical vapor deposition (CVD) method. Atomic Force Microscopy (AFM) and Raman spectroscopy reveal that the as-grown ultrathin MoSe2 layers change from a single layer to a few layers. Photoluminescence (PL) spectroscopy demonstrates that while the multi-layer MoSe2 shows weak emission peaks, the monolayer has a much stronger emission peak at ~ 1.56 eV, indicating the transition from an indirect to direct bandgap. Analysis based on transmission electron microscopy (TEM) confirms the single-crystallinity of MoSe2 layers with a hexagonal structure. In addition, photoresponse performance of photodetectors based on monolayer MoSe2 was studied for the first time. The devices exhibit a rapid response of ~ 60 ms and a good photoresponsivity of ~ 13 mA/W (a 532 nm laser with the intensity of 1 mW/mm2 and a 10 V bias), suggesting that the monolayer MoSe2 is a promising material for photodetection application.
- Published
- 2014
23. Floral-clustered few-layer graphene nanosheet array as high performance field emitter
- Author
-
Changzhi Gu, Lin Li, Junjie Li, Shibing Tian, Wangning Sun, and Xiaoxiang Xia
- Subjects
Materials science ,Field (physics) ,business.industry ,Graphene ,Nanotechnology ,Carbon nanotube ,law.invention ,Field electron emission ,law ,Electric field ,Optoelectronics ,General Materials Science ,business ,Graphene nanoribbons ,Nanosheet ,Common emitter - Abstract
Graphene sheet is expected to be a highly efficient field emitter due to its unique electrical properties and open surface with sharp edges. However, it is still a tremendous technical challenge to grow and align a graphene sheet in one particular direction to protrude its sharp edges for good field emission. Here, we report an ideal graphene field emitter of flower-like graphene nanosheets grown on a silicon nanocone array, wherein nanocone array guides the alignment of vertical nanosheets and produces high-density sharp edge protrusions on the conical tip. We observe high performance and stable field emission with low turn-on fields from floral-clustered graphene nanosheets. Protrusive sharp edges on the nanocone tip and optimized spacing between clusters both appear to locally enhance the electric field and dramatically increase field emission. Our new graphene emitter design provides a robust approach to the prospect for development of practical electron sources and advanced devices based on graphene field emitters.
- Published
- 2012
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.