Abstract:
Organic N-heterocyclic based donor-acceptor derivatives have drawn great attention
due to their various potential applications in organic light emitting diodes,1 sensors,2 lasers3
and biomedical applications.4 The precise tuning of donor-acceptor interactions allows the
modification of their electron affinities and their ionization potentials, giving rise to new
functional material with tunable band gaps and, consequently, having very different electronic
and optical properties. In this regard, developing organic π conjugated molecules with donoracceptor
or donor-π-acceptor structures based on N-heterocyclic molecules is fascinating due
to their unique optical and electronic properties. It is well known that optical and electronic
properties of donor-acceptor systems are dependent on excited state dynamics involving
intramolecular charge transfer state (ICT). Therefore, the photophysical properties such as the
emission, fluorescent quantum yield, fluorescence lifetime, and phosphorescent emission of
organic -conjugated chromophores highly depend on the ICT state of chromophores. It is
possible to tune the nature of the ICT state by manipulating the molecular structure of donoracceptor
systems, introducing different substituents, changing the reduction and oxidation
potential of acceptor and donor, respectively, changing the length of bridges, and changing the
geometry of chromophores.
