Chemistry Reference
In-Depth Information
SCHEME 5.28
Disulfide functionalized dendrimer
87
.
The composite films were assembled layer-by-layer via alternated and repeated
exposure of amino-functionalized substrates to solutions of the gold nanoparticles and
dendrimers [88-90].
During film deposition, the dendrimers served to cross-link the nanoparticles, and
thereby enabled the stepwise assembly of homogeneous and mechanically reinforced
films with precise control over the film thickness. When using a film as a chemical
resistor sensor device, high sensitivity to vapors of toluene and tetrachlorethane was
observed, but the undesired sensitivity to humidity was negligible. The short response
times, the high sensitivity to VOCs, and the low sensitivity to humidity made the
materials promising candidates for sensor applications.
5.9 OLED APPLICATIONS
In order tomake PPDs promising targets for organic light-emitting diode applications,
the building blocks should be easy to make and should cover the desired color range.
Usually the dendritic polyphenylenes themselves are not active fluorophores in the
visible due to their inherent steric hindrance between the phenylene units. As
demonstrated before, however, chromophores as perylene tetracarboxydiimide or
pyrene can be built into the core [50,70] or the scaffold [51,56], where the poly-
phenylene dendron shell is nonemissive and dilutes the dyes to considerable amount,
but helps to avoid aggregation and excimer formation.
Considering that the blue light-emitting diodes are still the most challengeable
ones in red green blue (RGB) light-emitting diodes (LEDs) displays [91-95], only the
