Energy Transfer from Polyaniline to Chlorophyll‑a Supramolecular Assembly in Nanohybrid

Abstract

Polyaniline (PANI)/chlorophyll-a (CHL-a) nanohybrids have been synthesized using two different oxidants (APS, FeCl₃) where the shape of polymeric nanostructure is influenced by CHL-a supramolecular arrangement in FeCl₃ oxidized system. The presence of stacked CHL-a porphyrin (evident from hypsochromic shift of Q absorption and shortening of lifetime at CHL-a emission) assists the evolution of nanorod cluster from PANI nanoflakes connected by 1D nanofibers. The radiative decay rate of CHL-a is found to increase in nanohybrids oxidized via FeCl₃ rather than those via the APS counterpart as there is a greater amount of CHL-a aggregates present in the former. This phenomenon indicates energy flux along supramolecular stacking. The significant quenching of the PL spectra and the shortening of the decay time of host PANI with increasing CHL-a concentration show the energy transfer from PANI to CHL-a is more pronounced in FeCl₃ oxidized system, due to shorter donor–acceptor distances. These findings clearly pave the way to architect CHL-a-based functional nanomaterial for effective energy transfer