Abstract
Singlet fission (SF), which involves the conversion of a singlet excited state into two triplet excitons, holds great potential to boost the efficiency of photovoltaics. However, losses due to triplet-triplet annihilation hamper the efficient harvesting of SF-generated triplet excitons, which limits an effective implementation in solar energy conversion schemes. A fundamental understanding of the underlying structure-property relationships is thus crucial to define design principles for cutting-edge SF materials, yet it remains elusive. Herein, we harness helical supramolecular polymers decorated with pentacene side groups to elucidate intermolecular SF dynamics in solution and promote the formation of long-lived mobile triplets. By leveraging the hydrogen bonding-driven assembly of benzene-1,3,5-tricarboxamide (BTA) cores into one-dimensional scaffolds, we direct the organization of appended pentacene motifs into long-range ordered helical frameworks. Dynamic interactions between weakly coupled SF pendants mediate singlet conversion within hundreds of picoseconds, affording triplet quantum yields well above 100%. Moreover, analysis of triplet dynamics with a Monte Carlo simulation model reveals that triplet diffusion along the supramolecular fibers is favored over annihilation, resulting in independent triplets exhibiting considerably slow decay on the time scale of tens of microseconds. The molecular packing within the assembly is tuned by subtle changes in monomer design to increase the rate and efficiency of SF while ensuring exceptionally long-lived mobile triplets, allowing to maintain triplet quantum yields exceeding 100% for at least 100 ns. This work opens new opportunities to exploit self-assembled supramolecular polymers as functional templates to achieve long-lived SF-generated triplets.
| Original language | English |
|---|---|
| Pages (from-to) | 28985–28993 |
| Number of pages | 9 |
| Journal | Journal of the American Chemical Society |
| Volume | 146 |
| Issue number | 42 |
| DOIs | |
| Publication status | Published - 23 Oct 2024 |
Bibliographical note
Publisher Copyright:© 2024 The Authors. Published by American Chemical Society.
Funding
The authors acknowledge Dr. Kealan Fallon and Prof. Luis Campos for discussion about the project and for providing the Pnc-NH2 precursor, Dr. Joost van der Tol for the AFM measurements, Dr. Tobias Schnitzer for the computational modeling of the BTA-Pnc oligomer, and the ICMS Animation Studio for the cartoon of the assembly. This work received funding from the European Research Council (H2020-EU.1.1., SYNMAT project, ID 788618) and the Dutch Ministry of Education, Culture and Science for the Gravitation Program Functional Molecular Systems (024.001.035). A.R., A.S., and R.H.F. acknowledge funding via the Engineering and Physical Sciences Research Council (EPSRC) via grant EP/V055127/1. G.L. acknowledges a Marie Sk\u0142odowska-Curie Postdoctoral Individual Fellowship (101026072) for financial support. The authors acknowledge Dr. Kealan Fallon and Prof. Luis Campos for discussion about the project and for providing the Pnc-NH precursor, Dr. Joost van der Tol for the AFM measurements, Dr. Tobias Schnitzer for the computational modeling of the BTA-Pnc oligomer, and the ICMS Animation Studio for the cartoon of the assembly. This work received funding from the European Research Council (H2020-EU.1.1., SYNMAT project, ID 788618) and the Dutch Ministry of Education, Culture and Science for the Gravitation Program Functional Molecular Systems (024.001.035). A.R., A.S., and R.H.F. acknowledge funding via the Engineering and Physical Sciences Research Council (EPSRC) via grant EP/V055127/1. G.L. acknowledges a Marie Sk\u0142odowska-Curie Postdoctoral Individual Fellowship (101026072) for financial support. 2