Related Experiment Video
Updated: Jun 17, 2026
11:27
Single-Molecule Förster Resonance Energy Transfer Methods for Real-Time Investigation of the Holliday Junction Resolution by GEN1
Published on: September 18, 2019
Singlet Fission among Two Single Molecules
Sumanta Paul1, Oleksandr Yampolskyy1, Zehua Wu1
1Department of Chemistry, Johannes Gutenberg-Universität, Mainz 55128, Germany.
Journal of the American Chemical Society
|June 15, 2026
Summary
Single molecule spectroscopy reveals complex dynamics in singlet fission (SF). This study quanties the rates of triplet state formation and decay in terrylenediimide dimers, offering new insights into this solar energy conversion process.
Area of Science:
- Photophysical processes
- Materials science
- Spectroscopy
Background:
- Singlet fission (SF) generates two triplet excited states from one singlet excitation, enhancing exciton multiplication for solar energy applications.
- SF typically outcompetes radiative decay, making single-molecule studies challenging.
Purpose of the Study:
- To investigate the mechanistic details of singlet fission at the single-molecule level.
- To analyze the dynamics and heterogeneities of SF in terrylenediimide (TDI) dimers.
Main Methods:
- Single-molecule spectroscopy was employed to study TDI dimers at room and cryogenic temperatures.
- Photon emission streams from individual dimers were analyzed to determine SF rates.
Main Results:
- Static and dynamic heterogeneities in SF rates were observed, indicated by broad rate distributions and fluctuations.
- Delayed fluorescence and occasional rate fluctuations during spin evolution were detected.
- Cryogenic experiments suggested the formation of a coherent multiexciton superposition state.
Conclusions:
- Single-molecule spectroscopy provides a new approach to study SF mechanisms obscured by ensemble averaging.
- The findings offer detailed insights into the complex kinetics and quantum phenomena governing singlet fission.
Related Concept Videos
01:20Binary Fission
Fission is the division of a single entity into two or more parts, which regenerate into separate entities that resemble the original. Organisms in the Archaea and Bacteria domains reproduce using binary fission, in which a parent cell splits into two parts that can each grow to the size of the original parent cell. This asexual method of reproduction produces cells that are all genetically identical.
01:26Binary Fission
Binary fission is the primary mode of asexual reproduction in prokaryotes, such as bacteria. It results in the production of two genetically identical daughter cells. This highly efficient process ensures the rapid propagation of bacterial populations under favorable conditions and involves coordinated cellular and molecular events.DNA Replication and SeparationThe process begins with the replication of the bacterial chromosome. The circular DNA molecule unwinds at a specific origin of...
02:50Nuclear Fission
Many heavier elements with smaller binding energies per nucleon can decompose into more stable elements that have intermediate mass numbers and larger binding energies per nucleon—that is, mass numbers and binding energies per nucleon that are closer to the “peak” of the binding energy graph near 56. Sometimes neutrons are also produced. This decomposition of a large nucleus into smaller pieces is called fission. The breaking is rather random with the formation of a large number of different...
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
01:03Single-Strand DNA Binding Proteins
For successful DNA replication, the unwinding of double-stranded DNA must be accompanied by stabilization and protection of the separated single strands of the DNA. This crucial task is performed by single-strand DNA-binding (SSB) proteins. They bind to the DNA in a sequence-independent manner, which means that the nitrogenous bases of the DNA need not be present in a specific order for binding of SSB proteins to it. The binding of SSB proteins straightens single-stranded DNA (ssDNA) and makes...
01:13¹H NMR: Complex Splitting
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.