The Growth Mechanism Of Self-assembled Manganese Phthalocyanine On Bi(111) Surface

In recent years, studies have found organic molecules self-assembled thin films of materials with novel optical, electrical, catalytic functions and features, especially in the production of organic semiconductor optoelectronic devices, synthetic biomimetic materials, efficient catalytic materials and solar cells [4-8] broad prospects for application of such research in this area has been the subject of much concern and attention researchers. Scanning tunneling microscopy (STM) is an advanced surface analysis equipment, not only can use it to observe the morphology of atomic resolution images, but it can also be displayed in real space by the electronic structure of the material. In this paper, we use a scanning tunneling microscope to study the manganese phthalocyanine molecules (MnPc) The formation of self-assembled film morphology and growth mechanisms on (111) surface of Bi. Through experimental study we found:The adsorption and self-assembly of manganese phthalocyanine (MnPc)molecules on Bi(111) are investigated by means of low-temperature scanning tunneling microscope (STM). At low temperature (4.6K), isolated MnPc molecules adsorb flatly on Bi(111) with the two opposing lobes aligned in the direction of surface base vectors. When temperature is increased to 78 K, individual MnPc molecules rotate around the central Mn ion until they meet other MnPc molecules forming self-assembled structures. With the coverage increasing, MnPc molecules show a structural evolution from single molecules to molecular chains, and finally to 2-D domains.In particular, high-resolution STM images reveal there are two mirrored molecular chains with alternating arrangement in the 2-D domains. Annealing the sample to room temperature leads to a phase separation such that each molecule chains appeared only in the respective domains.