Roel Tempelaar: Resolving the dark product states in singlet fission through modeling of nonlinear spectroscopy
|Wanneer:||do 15-06-2017 11:00 - 12:00|
Singlet fission is a molecular process in which a singlet excitation converts into two triplet excitons. Over the recent years, considerable attention has been paid to this phenomenon driven by both fundamental and technological interests. With regards to the latter, singlet fission holds promise to break the Shockley-Queisser limit for single-junction solar cells. However, a detailed understanding of singlet fission is hampered by the optical dark nature of the product triplet states, which renders the process hard to resolve once the singlet exciton is depopulated. Recently, advances in nonlinear spectroscopy have allowed for the study of singlet fission materials with improved time and energy resolution, in particular by means of 2D electronic spectroscopy (2DES). The resulting experimental data points towards the functional importance of strong coupling between electronic and vibrational degrees of freedom. In my talk, I will present our recently developed microscopic model of singlet fission in which such vibronic coupling is treated non-perturbatively. Based on this model, I will give a detailed interpretation of the recent spectroscopic measurements, and present microscopic details that are experimentally inaccessible.