Molecular Design and Control Over the Morphology of Self-Assembled Films on Ionic Substrates

International audienceAchieving control over formation of molecular fi lms on insulating substratesis important for designing novel 2D functional materials and devices. Tostudy the main factors governing successful control, organic molecules withinterchangeable polar functional groups, a variable length aromatic body, andfl exible hydrocarbon chains are designed, synthesized and then deposited onthe (001) surfaces of bulk sodium chloride, potassium chloride, and rubidiumchloride. The deposited structures are imaged using noncontact atomic forcemicroscopy and modeled using density functional theory. The results showthat it is possible to form large-scale, highly ordered, 2D, porous moleculardomains (&gt10 4 pores), which are stable at room temperature, and to controlthe size of the 2D pores. Alternatively, it is possible to form line structures ordroplets (through molecular dewetting) by altering the molecular structure orchanging the substrate lattice constant. Theoretical calculations explain thebalance of the molecule–molecule and molecule–surface interactions and thestructure and thermodynamic stability of the grown fi lms