8/13/2019 Synthesis of nanoparticles for oled
2/2
involves mixing the emission from red, green and blue phosphors
with a UV LED chip used for
excitation. The disadvantage of such a device is low efficiency
of red phosphor, due to large stroke
shifts and the need for complex coating technology. Furthermore,
mixing powders and finding
high-efficiency compounds are more difficult for this device.
However, there are several benefits,
including high color rendering index, high luminous efficiency,
and stable light color that are almost
independent of the changed current. Another bright idea is to
mix different sizes of quantum dot to
increase spectral width across the visible region and so get
perfect white. However a serious
drawback arises from overlap of absorption and emission bands.
This causes serious re-absorption at
finite concentration, which in turn moves the emission further
to the red. Also it was reported that
simply capped QD were unstable when illuminated with UV light,
as force between QD and capping
agents are generally weak.
