Chemical Research in Chinese Universities ›› 2020, Vol. 36 ›› Issue (4): 685-689.doi: 10.1007/s40242-020-0210-3

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Two-dimensional Molecular Phase Transition of Alkylated-TDPB on Au(111) and Cu(111) Surfaces

ZHANG Junjie1, WANG Can1,2, DUAN Ruomeng3, PENG Chencheng1, YANG Biao1,4, CAO Nan1,4, ZHANG Haiming1, CHI Lifeng1   

  1. 1. Institute of Functional Nano & Soft Materials(FUNSOM), Soochow University, Suzhou 215123, P. R. China;
    2. Université de Strasbourg, CNRS, ISIS,;
    8 alleé Gaspard Monge, 67000 Strasbourg, France;
    3. School of Materials Science and Engineering, Dongguan University of Technology, Dongguan 523830, P. R. China;
    4. Physics Department E20, Technical University of Munich, D-85748 Garching, Germany
  • Received:2020-06-27 Revised:2020-07-10 Online:2020-08-01 Published:2020-07-30
  • Contact: CHI Lifeng E-mail:chilf@suda.edu.cn
  • Supported by:
    Supported by the National Natural Science Foundation of China(Nos.21673154, 21790053, and 51821002), the National Key R&D Program(MOST) of China(No.2017YFA0205002), the Project of the Collaborative Innovation Center of Suzhou Nano Science&Technology, China, the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD), China and the 111 Project, China.

Abstract: The derivatives of aromatic cores bearing alkyl chains with different lengths are of potential interest in on-surface chemistry, and thus have been widely investigated both at liquid-solid interfaces and in vacuum. Here, we report on the structural evaluation of self-assembled 1,3,5-tri(4-dodecylphenyl)benzene(TDPB) molecules with increased molecular coverages on both Au(111) and Cu(111) surfaces. As observed on Au(111), rhombic and herringbone structures emerge successively depending on surface coverage. In the case of Cu(111), the same process of phase conversion is also observed, but with two distinct structures. In comparison, the self-assembled structures on Au(111) surface are packed more densely than that on Cu(111) surface under the same preparation conditions. This may fundamentally result from the higher adsorption energy of TDPB molecules on Cu(111), restricting their adjustment to optimize a thermodynamically favorable molecular packing.

Key words: Self-assembly, Scanning tunneling microscope, Phase transition, Adsorption energy