2017/10/26 by Cameron B. Dover, Joseph K. Gallaher, Dover, Cameron B. +11
Agricultural and Biological Sciences · Engineering · #Advanced Thermodynamic Systems and Engines #Chemical Physics (physics.chem-ph) #FOS: Physical sciences #Nuclear reactor physics and engineering #Radiation Effects and Dosimetry
paper · pdf · doi:10.48550/arxiv.1710.09948
openalex publication_date 2017/10/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Singlet fission is a process whereby two triplet excitons can be produced from one photon, potentially increasing the efficiency of photovoltaic devices. Endothermic singlet fission is desired for maximum energy conversion efficiency, and such systems have been shown to form an excimer-like state with multi-excitonic character prior to the appearance of triplets. However, the role of the excimer as an intermediate has, until now, been unclear. Here we show, using 5,12-bis((triisopropylsilyl)ethynyl)tetracene in solution as a prototypical example, that, rather than acting as an intermediate, the excimer serves to trap excited states, to the detriment of singlet fission yield. We clearly demonstrate that singlet fission and its conjugate process, triplet-triplet annihilation, occur at a longer intermolecular distance than an excimer intermediate would impute. These results establish that an endothermic singlet fission material must be designed that avoids excimer formation, thus allowing singlet fission to reach its full potential in enhancing photovoltaic energy conversion.