title: Strong triplet excited-state absorption in a phenanthrolinyl iridium(III) complex with benzothiazolylfluorenyl-substituted ligands.
abstract: Femtosecond transient difference absorption (fs TA) measurements, together with a series of open-aperture Z scans at picosecond and nanosecond pulse widths and a variety of pulse energies, were performed on a 1,10-phenanthrolinyl iridium(III) complex bearing ligands containing a benzothiazolylfluorenyl motif. An analysis of decay data from the fs TA experiment yields a value of 1.24±0.26  ns for the singlet excited-state lifetime τ(S) of the complex. By fitting the Z scans to a five-level dynamic model incorporating the independently measured value of τ(S) and previously reported values of the complex's triplet quantum yield (0.13) and triplet excited-state lifetime (230 ns), we obtain values of 3.5×10(-17)  cm(2) (singlet) and 5.0×10(-16)  cm(2) (triplet) for the excited-state absorption cross-sections of the complex in toluene solution at 532 nm; the latter value represents one of the largest triplet excited-state absorption cross-sections ever reported at this wavelength. The ratio of the triplet excited-state cross-section to the ground-state absorption cross-section exceeds 3800.
authors: Timothy M
authors: TM
authors: Pritchett
authors: Michael J
authors: MJ
authors: Ferry
authors: William M
authors: WM
authors: Shensky
authors: Andrew G
authors: AG
authors: Mott
authors: David J
authors: DJ
authors: Stewart
authors: Stephanie L
authors: SL
authors: Long
authors: Joy E
authors: JE
authors: Haley
authors: Zhongjing
authors: Z
authors: Li
authors: Wenfang
authors: W
authors: Sun