Excellent photostability of phosphorescent nanoparticles and their application as a color converter in light emitting diodes.

The phosphorescent Ir(III) complexes were modified by allylation and consecutive hydrosilylation, and covalently incorporated into the silica nanoparticles by hydrolysis and condensation reaction with TEOS. These nanoparticles showed an excellent photochemical and thermal stability, and a very high luminescent efficiency due to the blocking of O(2) quenching and suppression of energy transfer through the amorphous silica solid solution. The limited mobility of complexes in the silica matrix also resulted in a decrease in the vibration relaxation and restrained the nonradiative decay. It is expected that these photostable and very efficient phosphorescent nanoparticles can be used in various fields ranging from nanobiotechnology to nanoengineering materials, where long-term stability with the high luminescent efficiency is required. As an example of the use of excellent photostability, a preliminary test result in which they are used as a color converter in a light emitting diode (LED) is also discussed.