One-dimensional molecular chains formed by Sierpiński triangles on Au(111)

One-dimensional molecular chains with Sierpiński triangles as building blocks were prepared on Au(111) and studied by low-temperature scanning tunneling microscopy. Fractal Sierpiński triangles were stabilized by the coordination interaction between 1,3-bi(4-pyridyl) benzene (BPyB) and Co atoms. At low coverages, Sierpiński triangles of high orders were observed. At high coverages, Sierpiński triangles formed two types of one-dimensional molecular chains. The high coverages and matching between molecular size and surface lattices are attributed to the formation of molecular chains.