International Journal of Thermophysics   2015 年 36 卷 5-6 期

2015.06.22

In this study, a sonochemical approach is developed to prepare rare-earth (Y³⁺, Tb³⁺, or Er³⁺)-doped zinc oxide nanocrystals in an ionic liquid: 1-butyl-3-methylimidazolium tetrafluoroborate. The nanomaterials are characterized by transmission electron microscopy and X-ray diffraction. The results show that the crystalline samples have a spherical shape with a diameter around 7.5??nm. In the band-edge transition region, the photoacoustic (PA) intensity of the samples changes remarkably. Different PA intensities of the samples are interpreted by comparison with their luminescence spectra. The results indicate that the luminescence properties of zinc oxide can be tuned by rare-earth doping. The luminescence quantum yields have been determined to be 12??%, 9.3??%, and 1.1??% for Tb³⁺-, Y³⁺-, and Er³⁺-doped ZnO samples, respectively. Moreover, a possible mechanism is proposed to interpret the formation of the nanocrystals.