o-Nitrobenzyl Functionalized Photopatternable Conjugated Polymers.
Abstract: Organic electronics often use conjugated polymers to enable
optoelectronic activity. It is a common practice to modify a polymer with alkyl side chains
that improve its solubility so that solution processing can be used to make solid state
samples. While this approach has proven useful, it introduces some additional issues: i) if
the device contains multiple layers, any solution based ... read moreprocessing must not perturb already
existing layers, and ii) the solubilizing side chains occupy space in the solid state with
atoms that have no optoelectronic activity. This thesis describes a novel technique where
conjugated polymers are functionalized with solubilizing side chains that can be removed by
irradiating the polymer with ultraviolet light. Chapter 2 describes the use of
photocleavable o-nitrobenzyl (NB) ester solubilizing side chains on a polythiophene
backbone. This methodology works in both solution leading to aggregation, and in the solid
state leading to an insoluble film. Prior work on changing the solubility of polythiophene
relied on using heat as the external stimulus to initiate the side chain cleavage. Chapter
3 describes the further exploration of NB side chains on polythiophene. This work examines
the modification of the NB group to increase the rate of photocleavage, the use of
donor-accepter polymer backbones, and patterning. Finally, Chapter 4 describes the
application of this methodology to new low-bandgap conjugated polymers that absorb light in
the near-infrared (NIR) region.
Thesis (Ph.D.)--Tufts University, 2015.
Submitted to the Dept. of Chemistry.
Advisor: Samuel Thomas.
Committee: Clay Bennett, Elena Rybak-Akimova, and Erik Berda.
Keywords: Organic chemistry, and Polymer chemistry.read less