Acta Chimica Sinica ›› 2020, Vol. 78 ›› Issue (4): 344-354.DOI: 10.6023/A19120455 Previous Articles     Next Articles



邓颖怡a, 钱银银a, 谢颖a, 张磊b, 郑冰a, 娄原青a, 于海涛a   

  1. a 黑龙江大学 化学化工与材料学院 功能无机材料化学教育部重点实验室 哈尔滨 150080;
    b 黑龙江大学 数学科学学院 黑龙江省复杂系统理论与计算重点实验室 哈尔滨 150080
  • 投稿日期:2019-12-29 发布日期:2020-03-26
  • 通讯作者: 郑冰
  • 基金资助:

Effect of Li Adsorption on Work Function Modulation of Bilayer α-Borophene: A Theoretical Study

Deng Yingyia, Qian Yinyina, Xie Yinga, Zhang Leib, Zheng Binga, Lou Yuanqinga, Yu Haitaoa   

  1. a School of Chemistry and Materials Science, Key Laboratory of Functional Inorganic Material Chemistry(Ministry of Education), Heilongjiang University, Harbin 150080, China;
    b Department of Mathematics, Heilongjiang Provincial Key Laboratory of Complex Systems Theory and Computation, Heilongjiang University, Harbin 150080, China
  • Received:2019-12-29 Published:2020-03-26
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Nos. 21601054, 11871198, 11801116), the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province of China (No. UNPYSCT-2017126), and the Training Program of Innovation and Entrepreneurship for Undergraduates of Heilongjiang Province (No. 201910212073).

As a new member of the two-dimensional nanomaterial family, borophene is regarded as a potential material platform for nanoscale electronic devices. Especially, borophene-based electrodes have potential application values in light-emitting diodes, organic light-emitting diodes, organic solar cells and field emitters. Therefore, the work function modulation (to an optimal value) of borophene is highly important to maximize the energy conversion efficiency and performance of the device. Based on the first-principles density functional theory, the effects of Li adsorption on the structure, electronic properties and work function of double-layer α-borophene (DBBP) are studied. The calculation results show that Li adsorption can effectively adjust the work function of DBBP from 4.65 eV to 1.96~4.46 eV with different Li contents. This engineering range is superior to what are reported in the literatures for Li-adsorbed monolayer BBP (modified from 4.16 eV to 2.31~3.67 eV), and double-layer graphene with intercalated Li (3.4~3.9 eV) and K (3.3~3.8 eV). The work functions of Li2(D)/DBBP (3.73 eV) and Li3(D)/DBBP (2.91 eV) are close to the commonly used electrode materials Mg and Ca, respectively, while the work function of Li4(D)/DBBP is even lower than Ca. In addition, the factors that affect the work function reduction of Lin/DBBP relative to DBBP, such as configuration, substrate deformation, binding energy, electron transfer, charge rearrangement, electrostatic potential, vacuum and Fermi level, are systematically studied. The results demonstrate that the decrease in the Lin/DBBP work function is mainly due to the change in Fermi level, while the change in vacuum level only plays a minor role. Apart from that, the deformation of the substrate does not have a positive effect on the reduction of the Lin/DBBP work function, but the electron transfer from the adsorbed atoms to the matrix (charge redistribution caused by chemical effects) is the inherent reason for the decrease in the Lin/DBBP work function. This study shows that Li adsorption is a simple and effective method to reduce the work function of DBBP. Due to its metallic character and extremely low work function, Li-adsorbed DBBP nanomaterials can be utilized as cathode materials in electronic devices.

Key words: borophene, work function, adsorption, electronic structure, binding energy