Luminescence of macrocyclic mononuclear Dy III complexes and their immobilization on functionalized silicon-based surfaces

Abstract

Two mononuclear DyIII complexes, [Dy(L1)(NCS)3] (Dy-EDA) and [Dy(L2)-(NCS)3] (Dy-DAP), where Ln (n = 1−2) corresponds to a macrocyclic ligand derived from 2,6-pyridinedicarboxaldehyde and ethylenediamine (L1) and 1,3-diaminepropane (L2) wereimmobilized on functionalized silicon-based surfaces. This was achieved by the microcontactprinting (μCP) technique, generating patterns on a functionalized surface via covalent bondformation through the auxiliary −NCS ligands present in the macrocyclic complex species. Withthis strategy, it was possible to control the position of the immobilized molecules on the surface.Water contact angle measurements, X-ray photoelectron spectroscopy (XPS), infrared reflectionabsorption spectra (IRRAS), and atomic force microscopy (AFM) confirmed that the surfaceswere successfully functionalized. Furthermore, the optical properties in a broad temperature rangewere investigated for the as-prepared compounds. At room temperature, Dy-EDA was shown toemit in the deep blue region (Commission Internationald’Eclairage (CIE): (0.175, 0.128)), whileDy-DAP in the white region (CIE: (0.252, 0.312)). The different CIE values were due to the contribution of the strong emission ofthe ligand in the case of Dy-EDA. Besides, surface photoluminescence measurements showed that the immobilized complexesretained their bulk emissive properties