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Investigating molecular orbitals with submolecular precision on pristine sites and single atomic vacancies of monolayer h-BN

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Nano Research 2020年第8期13卷 2233-2238页

作者： Liwei Liu Thomas Dienel Gino Günzburger Teng Zhang Zeping Huang Cong Wang Roland Widmer Wei Ji Yeliang Wang Oliver Gröning School of Information and Electronics MIIT Key Laboratory for Low-Dimensional Quantum Structure and DevicesBeijing Institute of TechnologyBeijing100081China Empa Swiss Federal Laboratories for Materials Science and TechnologyDuebendorfCH-8600Switzerland Department of Materials Science and Engineering Cornell University and NSF-MIP Platform for the Accelerated RealizationAnalysisand Discovery of Interface Materials(PARADIM)IthacaNY14853USA Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials&Micro-nano Devices Renmin University of ChinaBeijing100872China

Understanding the influence of adsorption sites to the electronic properties of adsorbed molecules on two-dimensional(2D)ultrathin insulator is of essential importance for future organic-inorganic hybrid nanodevices.Here,the adsorption and electronic states of manganese phthalocyanine(MnPc)on a single layer of hexagonal boron nitride(h-BN)have been comprehensively studied by low-temperature scanning tunneling microscopy/spectroscopy and tight binding calculations.The frontier orbitals of the MnPc can change drastically by reversible manipulation of individual MnPc molecules onto and away from the single atomic vacancies at the h-BN surface.Particularly,the change of the molecular electronic configuration can be controlled depending on whether the atomic vacancy is below the metal center or the ligand of the MnPc.These findings give new insight into defect-engineering of the organic-inorganic hybrid nanodevices down to submolecular level.

关键词： hexagonal boron nitride phthalocyanine single atomic vacancy molecular orbital scanning tunneling microscopy

Plasmonic properties of graphene on uniaxially anisotropic substrates

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Chinese Physics B 2021年第3期30卷 473-478页

作者：汪圣川游斌张锐韩奎沈晓鹏王伟华 School of Materials and Physics China University of Mining and TechnologyXuzhou 221116China

Most of the current graphene plasmonic researches are based on the substrates with isotropic dielectric constant such as silicon.In this work,we investigate optical properties of graphene nanoribbon arrays placed on a uniaxially anisotropic substrate,where the anisotropy provides an additional freedom to tune the behaviors of graphene plasmons,and its effect can be described by a simple effective formula.In practice,the substrates of semi-infinite and finite thickness are discussed by using both the formula and full wave simulations.Particularly,the dielectric constants ε|| and ε⊥ approaching zero are intensively studied,which show different impacts on the transverse magnetic(TM) surface modes.In reality,the hexagonal boron nitride(hBN) can be chosen as the anisotropic substrate,which is also a hyperbolic material in nature.

关键词： graphene plasmonics anisotropy hexagonal boron nitride

Microstructural evolution and mechanical properties of h-BN composite ceramics with Y2O3-AlN addition by liquid-phase sintering

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Rare Metals 2020年第5期39卷 555-561页

作者： Bao-Fu Qiu Xiao-Ming Duan Zhuo Zhang Xing-Qi Liao Zhi-Hua Yang De-Long Cai De-Chang Jia Yu Zhou Key Laboratory of Advanced Structural-Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

hexagonal boron nitride(h-BN)composite ceramics were prepared by hot pressing with the addition of Y2O3 and AlN.The effects of different Y2O3–AlN contents on microstructural evolution,mechanical properties and thermal diffusion coefficients of h-BN composite ceramics were investigated.The results indicate that Y2O3–AlN forms a liquid phase during the sintering process achieving a good wettability with h-BN grains.In pure h-BN ceramic and h-BN composite ceramic with 40 wt%Y2O3–AlN,the h-BN grains grow well when controlled through solid-phase and liquid-phase diffusion,respectively.With the increase in Y2O3–AlN content,mechanical properties and thermal diffusion coefficients of h-BN composite ceramics first decrease and then increase,and the properties of h-BN composite ceramic with 10 wt%Y2O3–AlN are the inflection points.Such properties are highly related to the phase compositions,porosity and microstructure.

关键词： hexagonal boron nitride Y2O3–AlN Liquidphase sintering Wettability Mechanical properties

Heterogeneous h-BN@Cyclodextrin@Pd（II） Nanomaterial： Fabrication, Characterization and Application as a Highly Efficient and Recyclable Catalyst for C-C Coupling Reactions

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Chemical Research in Chinese Universities 2017年第5期33卷 811-815页

作者： SANG Rui CHENG Xu LI Weijian LUO Pengfei ZHANG Yong NIE Ruifang HAI Li WU Yong Key Laboratory of Drug Targeting and Drug Delivery System of Education Ministry Department of Medicinal Chemistry West China School of Pharmacy Sichuan University Chengdu 610041 P. R. China

An efficient and ligand-free method for the Suzuki and Heck cross-coupling reactions has been success- fully developed using h-BN-supported palladium as the catalyst. This green methodology represents a cost-effective and operationally convenient process for the synthesis of biaryls, stilbenes and acrylates. Wide scope of substrates, good to excellent yields, low reaction time, water as solvent, ligand-free, non-toxicity and recyclability of the catalyst are the main merits of these protocols. In addition, the h-BN@y-CD@Pd（II） nanomaterial has been fully characte- rized by TG, SEM, IR, XRD, XPS and ICP-AES analysis. And it could be easily recovered and reused for at least nine times without any considerable loss of catalytic activity. Above all, this work demonstrates the possibility of using cyclodextrin-modified h-BN as an efficient support for the hydrophilic heterogeneous catalysts.

关键词： hexagonal boron nitride Cyclodextrin Heterogeneous catalysis C-C cross coupling Water

Giant and light modifiable third-order optical nonlinearity in a free-standing h-BN film

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Opto-Electronic Science 2022年第6期1卷 1-10页

作者： Jun Ren Han Lin Xiaorui Zheng Weiwei Lei Dan Liu Tianling Ren Pu Wang Baohua Jia Centre for Translational Atomaterials School of ScienceComputing and Engineering TechnologiesSwinburne University of TechnologyP.O.Box 218HawthornVictoria 3122Australia School of Integrated circuits Tsinghua UniversityHaidianBeijing 100084China Institute for Frontier Materials Deakin UniversityGeelongVictoria 3216Australia Institute of Laser Engineering Beijing University of TechnologyChaoyangBeijing 100124China The Australian Research Council(ARC)Industrial Transformation Training Centre in Surface Engineering for Advanced Materials(SEAM)Swinburne University of TechnologyHawthornVictoria 3122Australia School of Science RMIT UniversityMelbourneVictoria 3000Australia

Recently,hexagonal boron nitride(h-BN)has become a promising nanophotonic platform for on-chip information devices due to the practicability in generating optically stable,ultra-bright quantum emitters.For an integrated information-processing chip,high optical nonlinearity is indispensable for various fundamental functionalities,such as all-optical modulation,high order harmonic generation,optical switching and so on.Here we study the third-order optical nonlinearity of free-standing h-BN thin films,which is an ideal platform for on-chip integration and device formation without the need of transfer.The films were synthesized by a solution-based method with abundant functional groups enabling high third-order optical nonlinearity.Unlike the highly inert pristine h-BN films synthesized by conventional methods,the free-standing h-BN films could be locally oxidized upon tailored femtosecond laser irradiation,which further enhances the third-order nonlinearity,especially the nonlinear refraction index,by more than 20 times.The combination of the free-standing h-BN films with laser activation and patterning capability establishes a new promising platform for high performance on-chip photonic devices with modifiable optical performance.

关键词： hexagonal boron nitride third-order nonlinearity laser oxidation optoelectronic device

First-principles study of the growth and diffusion of B and N atoms on the sapphire surface with h-BN as the buffer layer

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Journal of Semiconductors 2021年第8期42卷 66-72页

作者： Jianyun Zhao Xu Li Ting Liu Yong Lu Jicai Zhang College of Mathematics and Physics Beijing University of Chemical TechnologyBeijing 100029China State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China

Currently,the preparation of large-size and high-quality hexagonal boron nitride is still an urgent problem.In this study,we investigated the growth and diffusion of boron and nitrogen atoms on the sapphire/h-BN buffer layer by first-principles calculations based on density functional theory.The surface of the single buffer layer provides several metastable adsorption sites for free B and N atoms due to exothermic reaction.The adsorption sites at the ideal growth point for B atoms have the lowest adsorption energy,but the N atoms are easily trapped by the N atoms on the surface to form N-N bonds.With the increasing buffer layers,the adsorption process of free atoms on the surface changes from exothermic to endothermic.The diffusion rate of B atoms is much higher than that of the N atoms thus the B atoms play a major role in the formation of B-N bonds.The introduction of buffer layers can effectively shield the negative effect of sapphire on the formation of B-N bonds.This makes the crystal growth on the buffer layer tends to two-dimensional growth,beneficial to the uniform distribution of B and N atoms.These findings provide an effective reference for the h-BN growth.

关键词： hexagonal boron nitride buffer layer first-principles calculations molecular dynamics