CHARGE SEPARATION IN TRIPLET C-60 TMPD EXCIPLEXES

A transient de photoconductivity technique was used to demonstrate the formation of dipolar exciplexes of the triplet C-60 State with N,N,N',N'-tetramethyl-1,4-phenylenediamine (TMPD) in toluene. The dipole moment of the C-3(60)/TMPD exciplex was measured to be 35 +/- 4 D. Unit charges separated by 7.1 Angstrom, the center-to-center distance estimated for C-60 in van der Waals contact with TMPD, correspond to a dipole moment of 34 D. This implies that the triplet exciplex has essentially complete charge transfer. The lifetime of the exciplex was determined to be 7 +/- 2 ns.