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111.
Zhiyuan Sun Jing Xu Nsajigwa Mwankemwa Wenxing Yang Xianwen Wu Zao Yi Shanjun Chen Weibin Zhang 《理论物理通讯》2022,74(1):15503
Single-layer MoSi2N4,a high-quality two-dimensional material,has recently been fabricated by chemical vapor deposition.Motivated by this latest experimental work,herein,we apply first principles calculations to investigate the electronic,optical,and photocatalytic properties of alkali-metal(Li,Na,and K)-adsorbed MoSi2N4 monolayer.The electronic structure analysis shows that pristine MoSi2N4 monolayer exhibits an indirect bandgap(Eg=1.89 eV).By contrast,the bandgaps of one Li-,Na-,and K-adsorbed MoSi2N4 monolayer are 1.73 eV,1.61 eV,and 1.75 eV,respectively.Moreover,the work function of MoSi2N4 monolayer(4.80 eV)is significantly reduced after the adsorption of alkali metal atoms.The work functions of one Li-,Na-,and K-adsorbed MoSi2N4 monolayer are 1.50 eV,1.43 eV,and 2.03 eV,respectively.Then,optical investigations indicate that alkali metal adsorption processes substantially increase the visible light absorption range and coefficient of MoSi2N4 monolayer.Furthermore,based on redox potential variations after alkali metals are adsorbed,Li-and Na-adsorbed MoSi2N4 monolayers are more suitable for the water splitting photocatalytic process,and the Li-adsorbed case shows the highest potential application for CO2 reduction.In conclusion,alkali-metal-adsorbed MoSi2N4 monolayer exhibits promising applications as novel optoelectronic devices and photocatalytic materials due to its unique physical and chemical properties. 相似文献
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Xianwen Zhou Yiping Xu Yuhui Li Shubo Cheng Zao Yi Guohui Xiao Ziyi Wang Zhanyu Chen 《理论物理通讯》2022,74(11):115501
We propose a novel bilayer graphene terahertz metamaterial composed of double graphene ribbons and double graphene rings to excite a dynamically adjustable triple plasma-induced transparency (PIT) effect. The coupled mode theory (CMT) is used to explain the PIT phenomenon, and the results of the CMT and the finite-difference time-domain simulation show high matching degree. By adjusting the Fermi levels of graphene, we have realized a penta-frequency asynchronous optical switch. The performance of this switch, which is mainly manifested in the maximum modulation depth (MD = 99.97%) and the minimum insertion loss (IL = 0.33 dB), is excellent. In addition, we have studied the slow-light effect of this triple-PIT and found that when the Fermi level of graphene reaches 1.2 eV, the time delay can reach 0.848 ps. Therefore, this metamaterial provides a foundation for the research of multi-frequency optical switches and excellent slow-light devices in the terahertz band. 相似文献
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Tl2E (E=S or Se) nanorods were synthesized via solvothermal route with the addition of KI. The products were characterized with X-ray powder diffraction patterns and transmission electron microscope images. Their optical properties were studied by UV-vis transmittance and photoluminescence spectrum. The band gap of direct forbidden transitions was found larger than that of bulk materials, because of the blue shift caused by nanometer-scale crystalline particles due to quantum confinement effects. A possible growth mechanism is proposed. 相似文献
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Jing Chen Xianwen Zhang Jinbo Wei 《Mathematical Methods in the Applied Sciences》2015,38(17):3776-3791
We study the dynamics of three‐dimensional Vlasov‐Poisson system in the presence of a point charge with attractive interaction. Compared to the repulsive interaction,we cannot get a priori conversation law. Nevertheless,we are able to obtain bound of kinetic energy by introducing a Lyapunov functional. Combining this result with the concept of Diperna‐Lions flow, we establish global existence of weak solutions for this system. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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采用气固法制备了磷化钼-碳纳米花(MoP-CFs),通过简单的超声自组装将C60修饰在MoP-CFs表面,形成范德瓦耳斯异质结。研究其电催化析氢性能发现,C60的修饰能够有效降低电催化析氢过电位。其中,10% C60-MoP-CFs样品(10%为C60的质量分数)表现出最佳催化活性,在酸性和碱性条件下达到10 mA·cm-2的电流密度时,所需要的过电位分别为158和157 mV,并且具有至少20 h的电催化稳定性。C60与MoP-CFs之间强电子耦合作用促进电子由C60迁移到MoP-CFs表面,有助于减小电荷传输阻力,加快电催化析氢界面反应动力学过程。 相似文献
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