Thiol-modified gold nanoparticles deposited on silica support using dip coating

•Thin layers of gold were deposited on glass substrate.•Layers were modified by two different ligands, 1,4-dithiothreitol and l-glutathione.•Red shift of SPR band was observed in spectra after modification of Au by thiols.•Charge transfer between Au and S atoms leads to ferromagnetic behaviour of samples. In our work, we have prepared thin layers of gold nanoparticles deposited via dip coating technique on silica glass substrate. The prepared thin layers were modified by two different ligands, namely 1,4-dithiothreitol (sample Au-DTT NPs) and l-glutathione (sample Au-GSH NPs). The spectral, structural and magnetic properties of the prepared samples were investigated. The modification of Au nanoparticles with thiol ligands leads to change of their plasmon resonance fields, as indicated by UV–vis spectra. The magnetic measurements showed that the magnetization of the samples is composed from two magnetic contributions: diamagnetic contribution and low field ferromagnetic contribution. Our experimental results show that the charge transfer between Au and S atoms gives rise to the ferromagnetic behaviour of prepared thin layers.