Strong quenching of praseodymium f-f luminescence induced by a surface of Y2SiO5:Pr3+ nanocrystal

The direct comparison of the luminescence decay data obtained for nano- and bulk Y2SiO5:Pr3+ crystals has revealed that the concentration threshold of luminescence quenching is strikingly low for nanocrystals. Nanocrystal inhomogeneous stress field induced by a surface stimulates the segregation of the doped Pr3+ ions within the surface layer that provides the relaxation of elastic tension arising due to the difference of the ionic radii of Pr3+ and Y3+. The Pr3+ irregular distribution in the nanocrystal volume results in the Pr3+ local concentration increasing that facilitates the luminescence quenching.