TY - JOUR
T1 - Annihilation Dynamics of Molecular Excitons Measured at a Single Perturbative Excitation Energy
AU - Heshmatpour, C.
AU - Malevich, P.
AU - Plasser, F.
AU - Menger, M.
AU - Lambert, C.
AU - Šanda, F.
AU - Hauer, J.
N1 - Funding Information:
J.H., P.M., and C.H. thank Harald Ceymann for providing and synthesizing the sample. J.H. and C.H. acknowledge support by Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) through TUM International Graduate School of Science and Engineering (IGSSE), GSC 81, and funding by DFG under Germany’s Excellence Strategy (EXC 2089/1-390776260). F.Š. and C.H. acknowledge support by Czech Science Foundation (Grant No. 17-22160S). Mobility is supported by project “Exciton-exciton annihilation probed by nonlinear spectroscopy” (MSMT Grant No. 8J19DE009, DAAD-Projekt 57444962). P.M. acknowledges the support of the Alexander von Humboldt Foundation as well as the donor, the Federal Ministry for Education and Research.
Publisher Copyright:
Copyright © 2020 American Chemical Society.
PY - 2020/9/17
Y1 - 2020/9/17
N2 - Exciton-exciton annihilation (EEA) is a ubiquitous phenomenon, which may limit the efficiency of photovoltaic devices. Conventional methods of determining EEA time scales rely on measuring the intensity dependence of third-order signals. In this work, we directly extract the annihilation rate of molecular excitons in a covalently joined molecular trimer without the need to perform and analyze intensity dependent data by employing fifth-order coherent optical spectroscopy signals emitted into ±2k- 1 2k- 2 + k- 3 phase matching directions. Measured two-dimensional line shapes and their time traces are analyzed in the framework of the many-body version of the Frenkel exciton model, extended to incorporate annihilation dynamics. Combining double-sided Feynman diagrams with explicit simulations of the fifth-order response, we identify a single peak as a direct reporter of EEA. We retrieve an annihilation time of 30 fs for the investigated squaraine trimer.
AB - Exciton-exciton annihilation (EEA) is a ubiquitous phenomenon, which may limit the efficiency of photovoltaic devices. Conventional methods of determining EEA time scales rely on measuring the intensity dependence of third-order signals. In this work, we directly extract the annihilation rate of molecular excitons in a covalently joined molecular trimer without the need to perform and analyze intensity dependent data by employing fifth-order coherent optical spectroscopy signals emitted into ±2k- 1 2k- 2 + k- 3 phase matching directions. Measured two-dimensional line shapes and their time traces are analyzed in the framework of the many-body version of the Frenkel exciton model, extended to incorporate annihilation dynamics. Combining double-sided Feynman diagrams with explicit simulations of the fifth-order response, we identify a single peak as a direct reporter of EEA. We retrieve an annihilation time of 30 fs for the investigated squaraine trimer.
UR - http://www.scopus.com/inward/record.url?scp=85091191283&partnerID=8YFLogxK
U2 - 10.1021/acs.jpclett.0c02141
DO - 10.1021/acs.jpclett.0c02141
M3 - Article
C2 - 32842744
AN - SCOPUS:85091191283
SN - 1948-7185
VL - 11
SP - 7776
EP - 7781
JO - JOURNAL OF PHYSICAL CHEMISTRY LETTERS
JF - JOURNAL OF PHYSICAL CHEMISTRY LETTERS
IS - 18
ER -