Fang Yuan  Jun Xi  Hua Dong  Kai Xi  Wenwen Zhang  Chenxin Ran  Bo Jiao  Xun Hou  Alex K.‐Y. Jen  Zhaoxin Wu 《固体物理学:研究快报》2018,12(5)

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Chenbao Lu  Jian Yang  Shice Wei  Shuai Bi  Ying Xia  Mingxi Chen  Yang Hou  Ming Qiu  Chris Yuan  Yuezeng Su  Fan Zhang  Haiwei Liang  Xiaodong Zhuang 《Advanced functional materials》2019,29(10)

Electrochemically driven carbon dioxide (CO₂) conversion is an emerging research field due to the global warming and energy crisis. Carbon monoxide (CO) is one key product during electroreduction of CO₂; however, this reduction process suffers from tardy kinetics due to low local concentration of CO₂ on a catalyst's surface and low density of active sites. Herein, presented is a combination of experimental and theoretical validation of a Ni porphyrin‐based covalent triazine framework (NiPor‐CTF) with atomically dispersed NiN₄ centers as an efficient electrocatalyst for CO₂ reduction reaction (CO₂RR). The high density and atomically distributed NiN₄ centers are confirmed by aberration‐corrected high‐angle annular dark field scanning transmission electron microscopy and extended X‐ray absorption fine structure. As a result, NiPor‐CTF exhibits high selectivity toward CO₂RR with a Faradaic efficiency of >90% over the range from ?0.6 to ?0.9 V for CO conversion and achieves a maximum Faradaic efficiency of 97% at ?0.9 V with a high current density of 52.9 mA cm^?2, as well as good long‐term stability. Further calculation by the density functional theory method reveals that the kinetic energy barriers decreasing for *CO₂ transition to *COOH on NiN₄ active sites boosts the performance.  相似文献   

    

Guo Tian  Wenda Yang  Xiao Song  Dongfeng Zheng  Luyong Zhang  Chao Chen  Peilian Li  Hua Fan  Junxiang Yao  Deyang Chen  Zhen Fan  Zhipeng Hou  Zhang Zhang  Sujuan Wu  Min Zeng  Xingsen Gao  Jun‐Ming Liu 《Advanced functional materials》2019,29(32)

Conductive ferroelectric domain walls—ultranarrow configurable conduction paths—have been considered as essential building blocks for future programmable domain wall electronics. For applications in high‐density devices, it is imperative to explore the conductive domain walls in small confined systems, while earlier investigations have hitherto focused on thin films or bulk single. Here, an observation and manipulation of conductive domain walls confined within small BiFeO₃ nanoislands aligned in high‐density arrays are demonstrated. Using conductive atomic force microscopy, various types of conductive domain walls, including the head‐to‐head charged domain walls (CDWs), zigzag domain walls, and typical 71° head‐to‐tail neutral domain walls (NDWs), are distinctly visualized. The CDWs exhibit remarkably enhanced metallic conductivity with current of ≈nA order in magnitude and 10⁴ times larger than that inside domains (0.01–0.1 pA), while the semiconducting NDWs allow much smaller current (≈10 pA) than the CDWs. The substantial difference in conductivity for dissimilar walls enables manipulations of various wall conduction states for individual addressable nanoislands via electrical tuning of domain structures. A controllable writing of four distinctive states in individual nanoislands can be achieved, showing application potentials for developing multilevel high‐density memories.  相似文献   

    

Hailong Qiu  Tianyu Tang  Muhammad Asif  Xiaoxiao Huang  Yanglong Hou 《Advanced functional materials》2019,29(19)

Lithium (Li) metal is the most ideal anode material for high‐energy density batteries. However, the high activity of Li metal, the large volume change, and Li dendrite formation during cycling hinder its practical application. Herein, 3D porous Cu synthesized through a simple time‐saving hydrogen bubble dynamic template method is used as a host for the improved performance Li metal anode. Contrary to the planar Cu foil, the synthesized 3D porous structure can reduce the local current density, suppress the mossy/dendritic Li growth, and buffer the volume change in the Li metal anode. Highly stable Coulombic efficiency is achieved at different specific current densities (0.5, 1, and 2 mA cm^?2) with a capacity of 1.0 mAh cm^?2. Moreover, symmetrical Li|Li‐3D Cu cells show more stable cyclic performance with a lower overpotential even at a high current density of 3 mA cm^?2.  相似文献   

    

Wei Xia  Yangkun He  Houbing Huang  Hui Wang  Xiaoming Shi  Tianli Zhang  Jinghua Liu  Plamen Stamenov  Longqing Chen  John Michael David Coey  Chengbao Jiang 《Advanced functional materials》2019,29(24)

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Yi Zeng  Xin Du  Wei Hou  Xiaojiang Liu  Cun Zhu  Bingbing Gao  Liangdong Sun  Qiwei Li  Junlong Liao  Pavel A. Levkin  Zhongze Gu 《Advanced functional materials》2019,29(34)

Since the first report in 2007, polydopamine (PDA) coating has shown great potential as a general and versatile method to create functional nanocoatings on arbitrary substrates. Slow kinetics and poor controllability of the coating and secondary modification processes, however, have limited the further development of this attractive method. In this work, it is demonstrated that UV irradiation at 365 nm significantly accelerates the process of secondary modification of a PDA‐coated surface. The kinetics of both thiol and amine modifications of PDA are increased 12‐fold via UV irradiation, while the kinetics of metal ion reduction at the PDA interface is increased more than 550 times. Moreover, it is demonstrated that irradiating a PDA/metal nanoparticle composite surface with UV light at 254 nm leads to dissolution of the deposited metal nanoparticles (MNPs). Finally, grayscale metallic patterns, dynamic deposition, and removal of MNPs on PDA surface are realized with the proposed method.  相似文献   

    

Li Yang  Wanwan Hong  Yu Zhang  Ye Tian  Xu Gao  Yirong Zhu  Guoqiang Zou  Hongshuai Hou  Xiaobo Ji 《Advanced functional materials》2019,29(50)

Potassium‐ion batteries (PIBs) are currently drawing increased attention as a promising alternative to lithium‐ion batteries (LIBs) owing to the abundant resource and low cost of potassium. However, due to the large ionic radius size of K⁺, electrode material that can stably maintain K⁺ insertion/deintercalation is still extremely inadequate, especially for anode material with a satisfactory reversible capacity. As an attempt, nitrogen/carbon dual‐doped hierarchical NiS₂ is introduced as the electrode material in PIBs for the first time. Considering that the introduction of the carbon layer effectively alleviates the volume expansion of the material itself, further improves the electronic conductivity, and finally accelerates the charge transfer of K⁺, not surprisingly, NiS₂ decorated with the bifunctional carbon (NiS₂@C@C) material electrode shows excellent potassium storage performances. When utilized as a PIB anode, it delivers a high reversible capacity of 302.7 mAh g^?1 at 50 mA g^?1 after 100 cycles. The first coulombic efficiency is 78.6% and rate performance is 151.2 mAh g^?1 at 1.6 A g^?1 of the NiS₂@C@C, which are also notable. Given such remarkable electrochemical properties, this work is expected to provide more possibilities for the reasonable design of advanced electrode materials for metal sulfide potassium ion batteries.  相似文献   

    

Zhitao Rong  Xiuzhen Guo  Shaoshan Lian  Songwei Liu  Donghuan Qin  Yueqi Mo  Wei Xu  Hongbin Wu  Hong Zhao  Lintao Hou 《Advanced functional materials》2019,29(42)

Low‐cost solution‐processed CdTe nanocrystal (NC) solar cells always suffer from a high interface energy barrier and unbalanced hole/electron transport as well as anisotropic atom diffusion on the CdTe surface due to the limited amount of hole/electron interface materials or the difficulty in interface processing. In this work, a novel strategy is first adopted with gradient electron transport layer (CdS/CdSe) modification in the cathode and a new crosslinkable hole transport polymer (P‐TPA) implantation in the anode. The carrier recombination at interfaces is greatly decreased and thus the carrier collection is increased. Moreover, the light harvesting is improved both in short and long wavelength regions, making J_sc and V_oc increase simultaneously. A champion solar cell shows a very high power conversion efficiency of 9.2% and an outstanding J_sc of 25.31 mA cm^?2, which are among the highest values for all solution‐processed CdTe NC solar cells with a superstrate structure, and the latter value is even higher than that of traditional thick CdTe thin‐film solar cells (2 µm) via the high temperature close space sublimation method. This work demonstrates that facile surface modifications in both the cathode and anode with stepped extraction and organic–inorganic hybridization are very promising in constructing next‐generation highly efficient NC photovoltaic devices.  相似文献   

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Defen Guo  Kang Hou  Weijie Tang  Tao Chu 《半导体学报》2019,40(10):4-7

1.Introduction Silicon photonic integration is considered to be one of the most promising techniques in realizing high-density photonic integrated circuits because of its compact device size and CMOS compatible fabrication process.However,due to the large index contrast of silicon waveguides,silicon photonic devices are affected by the large polarization mode dispersion,polarization dependent loss and polarization dependent wavelength characteristics.Polarization transparent circuits and polarization diversity schemes,which have polarization rotators and splitters as common key devices,have been proposed to solve this issue[1–3].  相似文献   

    

Bao‐Hua Hou  Ying‐Ying Wang  Qiu‐Li Ning  Hao‐Jie Liang  Xu Yang  Jiawei Wang  Mingkai Liu  Jing‐Ping Zhang  Xinlong Wang  Xing‐Long Wu 《Advanced Electronic Materials》2019,5(3)

In order to develop the promising anode material for lithium‐ion batteries with high capacity, high rate performance, and long cycling stability, carbon‐coated FeP nanorods (FeP@C‐NR) vertically grown on the carbon nanotubes (CNTs), defined as CNTs⊥FeP@C‐NR, is successfully prepared via a simple two‐step process. This upgraded structure with slim FeP@C‐NR and dual‐carbon networks can not only buffer the huge volume change of the active materials during electrochemical reaction process to enhance the cycling stability but also accelerate the electrochemical kinetics. It is disclosed that such a unique structure exhibits a pseudocapacitance‐boosted ultrafast electrochemical kinetic and performs an excellent lithium storage performance. It delivers a high reversible capacity of ≈1130 mAh g⁻¹ at a current density of 0.05 A g⁻¹, remarkable cycling stability of 1129 mAh g⁻¹ after 300 cycles at 0.5 A g⁻¹, 1126 mAh g⁻¹ after 300 cycles at 1 A g⁻¹, and 350 mAh g⁻¹ after 3000 cycles at 2 A g⁻¹, and superior rate capability of 345 mAh g⁻¹ at 5 A g⁻¹. Moreover, a CNTs⊥FeP@C‐NR//LiFePO₄ full cell is assembled, which delivers a reversible capacity of 465 mA h g⁻¹ after 60 cycles at 0.5 A g⁻¹.  相似文献