Triplet states of fullerene C60 and C70 in solution: long intrinsic lifetimes and energy pooling

Autor:	R. B. Weisman, Margaret Fraelich
Rok vydání:	1993
Předmět:	chemistry.chemical_classification Quenching (fluorescence) Intersystem crossing Fullerene Reaction rate constant Chemistry Excited state General Engineering Analytical chemistry Physical and Theoretical Chemistry Triplet state Inorganic compound Excitation
Zdroj:	The Journal of Physical Chemistry. 97:11145-11147
ISSN:	1541-5740 0022-3654
DOI:	10.1021/j100145a002
Popis:	Lifetimes of the lowest triplet electronic states of C[sub 60] and C[sub 70] have been measured in room temperature benzene solution. With bimolecular quenching suppressed, the exponential lifetimes are found to be 133 [mu]s for C[sub 60] and > 2.2 ms for C[sub 70]. Triplet C[sub 60] and C[sub 70] are self-quenched with rate constants of 1.5 [times] 10[sup 7] and 8.5 [times] 10[sup 7] M[sup [minus]1] s[sup [minus]1], respectively. In mixed solutions of C[sub 60] and C[sub 70], triplet electronic excitation is efficiently and reversibly transferred at approximately 20% of the diffusion-limited rate. From the ratio of forward and reverse energy transfer rate constants, the T[sub 1]-S[sub 0] gap of C[sub 60] is deduced to be 102 [plus minus] 30 cm[sup [minus]1] greater than that of C[sub 70]. The long intrinsic lifetimes and rapid energy pooling suggest that improved efficiencies may be possible for many applications of fullerene photochemistry and photophysics. 24 refs., 3 figs., 1 tab.
Databáze:	OpenAIRE
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