The field of excitonics is related to the understanding, control and harnessing of electronic excitations in nanoscale environments. One of the goals of our group is the development of novel theoretical approaches for studying excitonic energy transfer in systems such as photosynthetic complexes, organic photovoltaic materials and nano-materials such as quantum dot assemblies.

We are carrying out fundamental work in the development of top-down and bottom-up approaches to the theoretical description of excitonic transfer processes in natural and artificial systems.

The theory of open quantum systems and its application to photosynthetic energy transfer.

Recent ultrafast experiments have shown evidence of long-lived, preserved coherences in photosynthetic energy transfer for up to 600 femtoseconds. Our research group is studying energy transfer in photosynthetic complexes using the theory of open quantum systems. We have developed a novel way for partitioning the contributions from different physical processes to global quantities such as the energy transfer efficiency. With our methodology, we find that the contribution of quantum coherence to the energy transfer efficiency in these complexes is of about 10% at room temperature.

We are currently working in extending our theory to more sophisticated models, and towards the understanding of memory effects in these systems.

Realistic description of excitonic energy transfer from first-principles.

Complementary to the top-down master equation approach, our group is developing approaches for the understanding of energy transfer phenomena based on sophisticated quantum chemistry methods and semi-classical approaches. These models will be used to provide parameters and interface with the open quantum systems approach.