Triplet-triplet annihilation (TTA) is an energy transfer mechanism where two molecules in their triplet excited states interact to form a ground state molecule and an excited molecule in its singlet state.[1] This mechanism is example of Dexter energy transfer mechanism.[2] In triplet-triplet annihilation, one molecule transfers its excited state energy to the second molecule, resulting in the first molecule returning to its ground state and the second molecule being promoted to a higher excited singlet state.[1]
Triplet-triplet annihilation was first discovered in the 1960s to explain the observation of delayed fluorescence in anthracene derivatives.[3][4][5][6]
^Parker, C. A.; Hatchard, C. G. (1962). "Delayed fluorescence from solutions of anthracene and phenanthrene". Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences. 269 (1339): 574–584. Bibcode:1962RSPSA.269..574P. doi:10.1098/rspa.1962.0197. S2CID98155331.
^Parker, C. A.; Hatchard, C. G. (1962). "Sensitized Anti-Stokes Delayed Fluorescence". Proc. Chem. Soc.: 386–387. doi:10.1039/PS9620000373.
^Parker, C. A.; Joyce, Thelma A. (1967). "Delayed fluorescence of anthracene and some substituted anthracenes". Chemical Communications (15): 744. doi:10.1039/C19670000744.