b -diketonates of Eu3+, red phosphors, supported on sol-gel functionalised silica

Abstract

Silica gel was functionalised with chloropropyl groups through the sol-gel process and then a β-diketone was incorporated into the support. Afterwards, Eu3+ ion and its chelates of 1,10-phen- antroline (phen) and 2,2’-bipyridine (bpy), red phosphors,were supported on such silica. Lumines- cence studies ofEu3+bound to this newmaterial have shown that there is an increase in the intensity of the emission when the ion is isolated by ligands in the silicamatrix. The energy transfer fromthe ligands phen and bpy to Eu3+ ion was observed in the excitation spectra, which present new bands ascribed to the ligands and/or complex. The Eu3+-functionalised silica was characterised by TGA and FTIR. TGAanalysis showed that there is a large loss ofmass around 300 °C,which is ascribed to the organic part of the material. The FTIR spectra presented the vibration modes for Si-C and -CH2-. The luminescent properties of the ions surrounding the Eu3+ ion were studied. The decay curve displayed a bi-exponential behaviour, indicating that there is more than one site of Eu3+ on the surface of the silica.