**3. Experimental details**

UV-vis absorbance spectra, X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence, cytotoxicity, and antibacterial methods were used. The NP solutions were placed in a 10 mL cuvette and their linear absorption spectra were found with a JASCO-V670 UV/VIS/NIR spectrometer with a wavelength range of 200–800 nm and a 1 nm resolution. Samples were drop casted onto carbon grids and cured at RT for transmission electron microscopy (TEM) examinations. To assess the size of the nanoparticles, the TEM investigation was performed on an FEI model TECHNAI G2 S-Twin. The NPS were analyzed using a Bruker D8 diffractometer at 40 kV, 30 mA, using Cu-K radiation at 1° min-1 scan rate and 0.02 step size across 2 = 20–80°. Eu and Sm complexes with Ag NPs and Au NPs had their photoluminescence spectra recorded on a HORIBA JOBIN YVON fluorescence spectrometer with excitation at 350 nm.
