Photochemical Degradation of Various Bridge-Substituted Fluorene-Based Materials

Photochemical degradation is an important
issue to be overcome
in advancing the lifetime of fluorene-containing conjugated polymers.
In order to optimize the inertness of the materials, a quantitative
measure for the efficiency of degradation is needed. Here, we introduce
a method to measure a relative quantum yield of the photochemical
degradation by monitoring the kinetics of the process by means of
UV/vis spectroscopy and liquid chromatography (LC) techniques. This
method is employed to a set of differently substituted 2,7-diphenylfluorenes,
serving as model compounds for polyfluorene materials. Our measurements
show that the quantum yield changes by orders of magnitude upon varying
the bridge substituents and that altered kinetics indicate changing
degradation mechanisms.