Triplet–Triplet Annihilation via the Triplet Channel in Crystalline 9,10-Diphenylanthracene

• Published in: The journal of physical chemistry letters Vol. 13; no. 37; pp. 8768 - 8774
• Main Authors: Yago, Tomoaki, Tashiro, Manami, Hasegawa, Kiichi, Gohdo, Masao, Tsuchiya, Syuta, Ikoma, Tadaaki, Wakasa, Masanobu
• Format: Journal Article
• Language: English
• Published: American Chemical Society 22-09-2022
• Subjects: Physical Insights into Energy Science
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.2c01839

Delayed fluorescence resulting from triplet–triplet annihilation in crystalline 9,10-diphenylanthracene was observed by means of steady-state fluorescence measurements under magnetic fields of ≤10 T. At five specific magnetic fields, four peaks and one dip in the magnetic field dependence of fluorescence intensity were observed, proving that exchange-coupled triplet pairs were generated in the course of triplet–triplet annihilation. The dip was in the opposite direction predicted for singlet channel triplet–triplet annihilation. Further analysis using the stochastic Liouville equation confirmed that the closest exchange-coupled triplet pair in crystalline 9,10-diphenylanthracene is quenched via both triplet channel and singlet channel triplet–triplet annihilation.