Sub‐Picosecond Singlet Exciton Fission in Cyano‐Substituted Diaryltetracenes1. (10th June 2015)

• Record Type: Journal Article
• Authors: Margulies, Eric A.; Wu, Yi‐Lin; Gawel, Przemyslaw; Miller, Stephen A.; Shoer, Leah E.; Schaller, Richard D.; Diederich, François; Wasielewski, Michael R.
• Is Part Of: Angewandte Chemie. Volume 127:Number 30(2015)
• Page Start: 8803
• Page End: 8807
• Publication Date: 2015-06-10
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201501355
• Languages: English
• ISSNs: 0044-8249

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Thin films of 5, 11‐dicyano‐6, 12‐diphenyltetracene (<bold>TcCN</bold>) have been studied for their ability to undergo singlet exciton fission (SF). Functionalization of tetracene with cyano substituents yields a more stable chromophore with favorable energetics for exoergic SF (2E(T₁)−E(S₁)=−0.17 eV), where S₁ and T₁ are singlet and triplet excitons, respectively. As a result of tuning the triplet‐state energy, SF is faster in <bold>TcCN</bold> relative to the corresponding endoergic process in tetracene. SF proceeds with two time constants in the film samples (τ=0.8±0.2 ps and τ=23±3 ps), which is attributed to structural disorder within the film giving rise to one population with a favorable interchromophore geometry, which undergoes rapid SF, and a second population in which the initially formed singlet exciton must diffuse to a site at which this favorable geometry exists. A triplet yield analysis using transient absorption spectra indicates the formation of 1.6±0.3 triplets per initial excited state.</p> </abstract>