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Soluble Diphenylhexatriene Dimers for Intramolecular Singlet Fission with High Triplet Energy.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Montanaro, Stephanie 
Leventis, Anastasia 
Sharma, Ashish 
Dowland, Simon A 

Abstract

Intramolecular singlet fission (iSF) facilitates single-molecule exciton multiplication, converting an excited singlet state to a pair of triplet states within a single molecule. A critical parameter in determining the feasibility of SF-enhanced photovoltaic designs is the triplet energy; many existing iSF materials have triplet energies too low for efficient transfer to silicon via a photon multiplier scheme. In this work, a series of six novel dimers based upon the high-triplet-energy, SF-active chromophore, 1,6-diphenyl-1,3,5-hexatriene (DPH) [E(T1) ∼ 1.5 eV], were designed, synthesized, and characterized. Transient absorption spectroscopy and fluorescence lifetime studies reveal that five of the dimers display iSF activity, with time constants for singlet fission varying between 7 ± 2 ps and 2.2 ± 0.2 ns and a high triplet yield of 163 ± 63% in the best-performing dimer. A strong dependence of the rate of fission on the coupling geometry is demonstrated. For optimized iSF behavior, close spatial proximity and minimal through-bond communication are found to be crucial for balancing the rate of SF against the reverse recombination process.

Description

Funder: Ramsay Memorial Trust


Funder: Winton Programme for the Physics of Sustainability

Keywords

34 Chemical Sciences, 3406 Physical Chemistry, 7 Affordable and Clean Energy

Journal Title

J Am Chem Soc

Conference Name

Journal ISSN

0002-7863
1520-5126

Volume Title

145

Publisher

American Chemical Society (ACS)
Sponsorship
Engineering and Physical Sciences Research Council (EP/P007767/1)
Engineering and Physical Sciences Research Council (EP/S003126/1)
EPSRC (EP/V055127/1)
Engineering and Physical Sciences Research Council (EP/P027741/1)