Recently, it has been reported that doped semiconductor nanoparticles can yield both high luminescence efficiencies and a spectacular lifetime shortening, which suggests that doped semiconductor nanoparticles form a new class of luminescent materials for various applications. From lifetime measurements and time-resolved spectroscopy we conclude that the (Formula presented) emission does not show a spectacular shortening of the decay time upon decreasing particle size as reported earlier. The luminescence of nanocrystalline (Formula presented) indeed has a short decay time (∼100 ns), but also shows a long ms range decay time. The short decay time is ascribed to a defect-related emission of ZnS, and is not from the decay of the (Formula presented) transition of the (Formula presented) impurity as suggested by other authors. The (Formula presented) transition of the (Formula presented) has a “normal” decay of about 1.9 ms. Based on our observations, we conclude that doped semiconductor nanoparticles do not form a new class of luminescent materials, combining a high efficiency with a short (ns) decay time.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 1 Jan 1998|