Towards large area surface functionalization with luminescent and magnetic lanthanoid complexes

Abstract

Homogeneous surface deposition of molecules over a large area of the substrate is difficult to achieve but extremely important for proposed applications of magnetic molecules in data storage, information processing or molecular spintronics. In this paper we report a simple method for large area surface functionalization with the aim of grafting complex molecules in an organized manner. A proof of concept is given by grafting the complexes [Ln₂(SYML)₃(H₂O)] (1 Ln = Eu(III), 2 Ln = Dy(III)) on the functionalized Si(100) and using a combination of techniques, including luminescence to track the process. We obtain a homogenous coverage of Si(100) wafers (from 0.5 cm × 0.5 cm to 1 cm × 1 cm) with complexes 1 and 2. Time of flight secondary ion mass spectroscopy (ToF-SIMS) confirms the presence of the expected molecular fragments on the surface. Grazing incidence X-Ray diffraction (GIXRD) measurements show preferred orientations and ordered domains of the molecules. The magnetic properties and anisotropy of the monolayer of grafted molecules are examined by X-Ray magnetic circular dichroism (XMCD), showing a fraction of molecules with a preferred orientation of their easy axis of magnetization at 30° with respect to the surface-normal.