Concentration quenching and photostability in Eu(dbm)3phen embedded in mesoporous silica nanoparticles

Ordered mesoporous silica nanoparticles (MSNs) were impregnated with different loadings of the luminescent complex tris(dibenzoylmethane) mono(1,10-phenanthroline)europium(III) (Eu(dbm)3phen), with the aim of increasing the luminescence by avoiding concentration quenching and having mainly in mind the application as spectral converter for multi-crystalline silicon solar cells. The morphological, structural and luminescence properties of the impregnated silica nanoparticles were characterized by N2 physisorption, X-ray diffraction, transmission electron microscopy, infrared spectroscopy, UV-visible spectroscopy and photoluminescence excitation and emission measurements. Photostability was tested under 1 sun (1000 W/m2) illumination for 24 h and the related effects were inspected by UV-visible and photoluminescence spectroscopies. Impregnation of the complex into 50-70 nm MSNs with pore size tailored around 2.9 nm depressed concentration quenching and allowed the use of complex loadings as high as 23 wt%. Sunlight irradiation caused a marked increase in the luminescence intensity.