Exploring a new class of singlet fission fluorene derivatives with high-energy triplets. Issue 7 (2nd February 2022)

• Record Type: Journal Article
• Authors: Mencaroni, Letizia; Carlotti, Benedetta; Elisei, Fausto; Marrocchi, Assunta; Spalletti, Anna
• Is Part Of: Chemical science. Volume 13:Issue 7(2022)
• Page Start: 2071
• Page End: 2078
• Publication Date: 2022-02-02
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d1sc07175k
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : We found that a stronger push–pull character favours SF, as long as the ICT does not act as a trap. The unique property of generating high-energy triplets ( ca. 2 eV) via SF makes these materials outstanding candidates for photovoltaic applications. Abstract : In this study, we report strong experimental evidence for singlet fission (SF) in a new class of fluorene-based molecules, exhibiting two-branched donor–acceptor structures. The time-resolved spectroscopic results disclose ultrafast formation of a double triplet state (occurring in few picoseconds) and efficient triplet exciton separation (up to 145% triplet yield). The solvent polarity effect and the role of intramolecular charge transfer (ICT) on the SF mechanism have been thoroughly investigated with several advanced spectroscopies. We found that a stronger push–pull character favors SF, as long as the ICT does not act as a trap by opening a competitive pathway. Within the context of other widely-known SF chromophores, the unconventional property of generating high-energy triplet excitons ( ca. 2 eV) via SF makes these materials outstanding candidates as photosensitizers for photovoltaic devices.