Abstract
Bose-Einstein condensation of excitons, in which excitons condense into a single coherent quantum state, known as an exciton condensate, enables frictionless energy transfer, but typically occurs under extreme conditions in highly ordered materials, such as graphene double layers. In contrast, photosynthetic light-harvesting complexes demonstrate extremely efficient transfer of energy in disordered systems under ambient conditions. Here, we establish a link between the two phenomena by investigating the potential for exciton-condensate-like amplification of energy transport in room-temperature light harvesting. Using a model of the Fenna-Matthews-Olson complex and accounting for intrachromophore electron correlation explicitly through the addition of multiple sites to the individual chromophores, we observe amplification of the exciton population in the particle-hole reduced density matrix through an exciton-condensate-like mechanism. The exciton-condensate-like amplification evolves with the dynamics of exciton transfer, and the nature of amplification is influenced by intra- and interchromophore entanglement, as well as the initial excitation model and number of sites per chromophore. Tuning intrachromophore coupling also increases the rate of exciton transfer with a maximum enhancement of nearly . The research provides fundamental connections between exciton condensation and exciton transport in light-harvesting complexes with potential applications for harnessing the exciton-condensate-like mechanism to enhance energy transfer in synthetic systems and create new materials capable of highly efficient energy transfer.
- Received 21 December 2022
- Revised 11 March 2023
- Accepted 20 March 2023
DOI:https://doi.org/10.1103/PRXEnergy.2.023002
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Popular Summary
All around us, green leaves capture energy from the sun. Meanwhile, physical phenomena, like superconductivity, are considered to be exotic. Here, the authors establish a link between these two seemingly unrelated phenomena and provide deep insight into energy transfer in quantum molecules and materials. A light-harvesting complex that occurs in green-sulfur bacteria is modeled to show that excitations in the complex, known as excitons, exhibit the beginnings of a condensation into a coherent quantum state. The single quantum state means that the excitons are working in concert to transfer energy with less friction-like loss. The exciton-like-condensation is associated with as much as a one hundred percent enhancement of the energy transfer in the light-harvesting system. These results can benefit design principles for energy transfer in quantum molecules and materials, which are important for realizing higher energy efficiency in devices with applications ranging from solar cells to computers.
