Abstract
Here, we report the influence of protactinium (Pa) on the optical behavior of ZnTe quantum dots. A nanocrystalline Zn1-xPaxTe (0 <= x <= 0.09) quantum dots prepared via poly [(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] assisted microwave approach. The X-ray diffraction showed that the ZnTe crystal preserves their zinc blende cubic structure at all Pa ions concentrations. The transmission electron microscopy revealed that the Pa dopants lead to an increase of the QDs size from 2.9 +/- 0.5 nm to 8.3 +/- 0.2 nm. The doping of Pa ions in the ZnTe QDs gives rise to a red shift of the optical absorption and luminescence spectral peaks. A remarkable improvement of the luminescence intensity and a decrease of the luminescence spectral width take place as a result of the doping of ZnTe with Pa ions. The quantum yield improved from 37 % to 95 %. The Stokes shift decreases with the increase of the Pa ions, implying the inhibition of the crystal defects due to the decrease of the number of Zn2+ vacancies. These exceptional comportments may pave the way for developing high quality laser diodes based on Zn1-xPaxTe semiconducting crystalline quantum dots.