At today's COPE science meeting we are discussing a paper, Coherent Intrachain Energy Migration in a Conjugated Polymer at Room Temperature, published in Science early this year by Collini and Scholes. The paper was chosen by Paul Schwenn.
There is also a longer much more detailed description of the work in J. Phys. Chem. A, which helps understand some of the details, particularly because it has some nice pedagogical figures.
Use is made of two-dimensional spectroscopy, for understanding that I find this Figure very helpful.
A key issue in photosynthesis and organic solar cells is the harvesting of light. One wants to channel excitons to "reaction centres" where charge separation will occur, as rapidly as possible and with the maximum efficiency. EET (electronic energy transfer) or exciton transfer usually occurs between molecules via the Forster mechanism (FRET). Often this is incoherent (and irreversible), i.e., there is no phase coherence between the wavefunction of the excitation on the donor and acceptor molecules. If phase coherence is present one can observed quantum interference effects such as Rabi oscillations associated with an excition oscillating back and forward between the donor and acceptor.
An important question is whether coherent transfer will increase the transfer rate and efficiency. Most people seem to claim it does but this is not clear to me. Some of these issues are discussed in an earlier post on similar experiments on a photosynthetic system.
Subscribe to:
Post Comments (Atom)
From Leo Szilard to the Tasmanian wilderness
Richard Flanagan is an esteemed Australian writer. My son recently gave our family a copy of Flanagan's recent book, Question 7 . It is...
-
Is it something to do with breakdown of the Born-Oppenheimer approximation? In molecular spectroscopy you occasionally hear this term thro...
-
If you look on the arXiv and in Nature journals there is a continuing stream of people claiming to observe superconductivity in some new mat...
-
I welcome discussion on this point. I don't think it is as sensitive or as important a topic as the author order on papers. With rega...
No comments:
Post a Comment