Research

Charge-carrier transport in polymers is still a debated question, particularly following the discovery of disordered organic semiconductors such as IDTBT and DPP-based polymers, which exhibit higher hole mobility than ordered polymers like PBTTT. We are actively working in this research space to understand charge-carrier dynamics in these disordered systems and to utilise this knowledge in the search for novel semiconducting polymers. We have also developed an efficient computational workflow for the rapid screening of high mobility polymers and formulated a strategy to quantitatively correlate charge localization characteristics and charge mobility. 

Charge-carrier dynamics in highly doped organic semiconductors are markedly distinct from those of their low-doped analogues, and this research field has recently seen a surge in interest due to their technological importance. It is imperative to consider both ion-carrier and carrier-carrier interactions to describe the charge dynamics in these systems, and to this end, we have recently developed an effective model reduction scheme to determine the electronic structure of highly doped polymers. We are presently working towards the utilization of this reduced model for evaluating charge transport characteristics in these systems.

Over the years, we have taken active part in the development of novel algorithms within the symmetrized density matrix renormalization group (DMRG) method and the fewest switches surface hopping (FSSH) method. These variants have been utilized to determine the electronic structures of quasi-one dimensional conjugated systems at the strong electron correlation limit as well as to probe charge dynamics in disordered conjugated molecules under the influence of nuclear motion. We have also developed computational workflows for the high-throughput screening of high mobility polymers and characterizing the electronic structures of disordered organic semiconductors at high doping limit. 

In an earlier study, we have identified a highly efficient energy transport regime due to transient exciton delocalization which rationalizes the experimental observations of several orders of magnitude larger singlet exciton diffusion length and diffusion coefficient in polymer nanofiber films. We have also analyzed the effects of transport parameters that can be tuned via chemical route and post-synthetic processing on exciton transport.