Time-Resolved VUV Excited Luminescence of $\hbox {Y}_{2}\hbox {O}_{3}\hbox {--} \hbox {Yb}$ Nanoparticles

Luminescence emission and excitation spectra as well as decay kinetics of Y₂O₃-Yb nanoparticles elaborated by the polyol mediated synthesis method have been measured at liquid helium temperature under VUV excitation. In nanoparticles the ratio of intensities of Charge Transfer Luminescence (CTL) and exciton excitation peaks differs from that for Y₂O_3-Yb single crystal, and changes with the particle size variation from 13 to 52 nm. This effect can be connected with the variation of excitation light scattering with particle dimensions. Two types of luminescence decay acceleration are observed. Acceleration of exponential decay time with decrease of nanoparticle size and the appearance of very fast decay component in small nanoparticles that we connected to energy transfer to the surface defects.