Visible electroluminescence from hybrid colloidal silicon quantum dot-organic light-emitting diodes

We demonstrate hybrid colloidal silicon quantum dot (SiQD)-organic light-emitting diodes with electroluminescence (EL) in the visible wavelengths. The device using blue photoluminescence (PL) SiQDs as emitters shows multiple EL peaks which are attributed to carrier recombination in the core quantum confinement states, the hole-transport-layer and the surface trap states, respectively. However, the red PL SiQD device shows a single EL peak consistent with the PL peak. These findings are in agreement with the previous report that large Stokes shift were observed for oxidized blue emission SiQDs due to oxide states while red emission SiQDs show negligible PL shift after oxidation. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3593382]