TY - JOUR

T1 - Intramolecular Triplet Diffusion Facilitates Triplet Dissociation in a Pentacene Hexamer

AU - Greißel, Phillip M.

AU - Thiel, Dominik

AU - Gotfredsen, Henrik

AU - Chen, Lan

AU - Krug, Marcel

AU - Papadopoulos, Ilias

AU - Miskolzie, Mark

AU - Torres, Tomás

AU - Clark, Timothy

AU - Brøndsted Nielsen, Mogens

AU - Tykwinski, Rik R.

AU - Guldi, Dirk M.

N1 - Funding Information: R.R.T. acknowledges funding from the Natural Sciences and Engineering Research Council of Canada (NSERC, grant no. RGPIN-2017-05052) and the Canada Foundation for Innovation (CFI). D.M.G. acknowledges financial support from the Deutsche Forschungsgemeinschaft (DFG) as part of SFB 953 “Synthetic Carbon Allotropes” and GU 517/32-1. T.T. acknowledges financial support from the Spanish MCIN/AEI/10.13039/501100011033 (PID2020-116490GB−I00, TED2021-131255B−C43), the Comunidad de Madrid and the Spanish State through the Recovery, Transformation and Resilience Plan [“Materiales Disruptivos Bidimensionales (2D)” (MAD2D-CM) (UAM1)-MRR Materiales Avanzados], and the European Union through the Next Generation EU funds. IMDEA Nanociencia acknowledges support from the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, Grant SEV2016-0686). T. T. also acknowledges the Alexander von Humboldt Foundation (Germany) for the A. v. Humboldt—J. C. Mutis Research Award 2023 (Ref [3].3-1231125—ESP-GSA). H.G. thanks the Danish Ministry of Higher Education and Science for an EliteForsk travel scholarship (6161-00051B). Open Access funding enabled and organized by Projekt DEAL. Funding Information: R.R.T. acknowledges funding from the Natural Sciences and Engineering Research Council of Canada (NSERC, grant no. RGPIN‐2017‐05052) and the Canada Foundation for Innovation (CFI). D.M.G. acknowledges financial support from the Deutsche Forschungsgemeinschaft (DFG) as part of SFB 953 “Synthetic Carbon Allotropes” and GU 517/32‐1. T.T. acknowledges financial support from the Spanish MCIN/AEI/10.13039/501100011033 (PID2020‐116490GB−I00, TED2021‐131255B−C43), the Comunidad de Madrid and the Spanish State through the Recovery, Transformation and Resilience Plan [“Materiales Disruptivos Bidimensionales (2D)” (MAD2D‐CM) (UAM1)‐MRR Materiales Avanzados], and the European Union through the Next Generation EU funds. IMDEA Nanociencia acknowledges support from the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, Grant SEV2016‐0686). T. T. also acknowledges the Alexander von Humboldt Foundation (Germany) for the A. v. Humboldt—J. C. Mutis Research Award 2023 (Ref [3] .3‐1231125—ESP‐GSA). H.G. thanks the Danish Ministry of Higher Education and Science for an EliteForsk travel scholarship (6161‐00051B). Open Access funding enabled and organized by Projekt DEAL. Publisher Copyright: © 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.

PY - 2023

Y1 - 2023

N2 - Triplet dynamics in singlet fission depend strongly on the strength of the electronic coupling. Covalent systems in solution offer precise control over such couplings. Nonetheless, efficient free triplet generation remains elusive in most systems, as the intermediate triplet pair 1(T1T1) is prone to triplet-triplet annihilation due to its spatial confinement. In the solid state, entropically driven triplet diffusion assists in the spatial separation of triplets, resulting in higher yields of free triplets. Control over electronic coupling in the solid state is, however, challenging given its sensitivity to molecular packing. We have thus developed a hexameric system (HexPnc) to enable solid-state-like triplet diffusion at the molecular scale. This system is realized by covalently tethering three pentacene dimers to a central subphthalocyanine scaffold. Transient absorption spectroscopy, complemented by theoretical structural optimizations and steady-state spectroscopy, reveals that triplet diffusion is indeed facilitated due to intramolecular cluster formation. The yield of free triplets in HexPnc is increased by a factor of up to 14 compared to the corresponding dimeric reference (DiPnc). Thus, HexPnc establishes crucial design aspects for achieving efficient triplet dissociation in strongly coupled systems by providing avenues for diffusive separation of 1(T1T1), while, concomitantly, retaining strong interchromophore coupling which preserves rapid formation of 1(T1T1).

AB - Triplet dynamics in singlet fission depend strongly on the strength of the electronic coupling. Covalent systems in solution offer precise control over such couplings. Nonetheless, efficient free triplet generation remains elusive in most systems, as the intermediate triplet pair 1(T1T1) is prone to triplet-triplet annihilation due to its spatial confinement. In the solid state, entropically driven triplet diffusion assists in the spatial separation of triplets, resulting in higher yields of free triplets. Control over electronic coupling in the solid state is, however, challenging given its sensitivity to molecular packing. We have thus developed a hexameric system (HexPnc) to enable solid-state-like triplet diffusion at the molecular scale. This system is realized by covalently tethering three pentacene dimers to a central subphthalocyanine scaffold. Transient absorption spectroscopy, complemented by theoretical structural optimizations and steady-state spectroscopy, reveals that triplet diffusion is indeed facilitated due to intramolecular cluster formation. The yield of free triplets in HexPnc is increased by a factor of up to 14 compared to the corresponding dimeric reference (DiPnc). Thus, HexPnc establishes crucial design aspects for achieving efficient triplet dissociation in strongly coupled systems by providing avenues for diffusive separation of 1(T1T1), while, concomitantly, retaining strong interchromophore coupling which preserves rapid formation of 1(T1T1).

KW - Oligoacene

KW - Photoenergy Conversion

KW - Singlet Fission

KW - Triplet Dissociation

KW - Ultrafast Spectroscopy

U2 - 10.1002/anie.202315064

DO - 10.1002/anie.202315064

M3 - Journal article

C2 - 38092707

AN - SCOPUS:85182813012

VL - 63

JO - Angewandte Chemie International Edition

JF - Angewandte Chemie International Edition

SN - 1433-7851

IS - 8

M1 - e202315064

ER -