U.S. Department of Defense


Date of this Version



Optical Materials 39 (2015)


U S. Government work.


By fitting femtosecond transient difference absorption time series at multiple wavelengths, the singlet excited-state lifetime of a particular platinum(II) 2,2’-bipyridyl complex bearing naphthalimidylethynyl- substituted fluorenyl-acetylide ligands was determined to be 83.5 ± 39 ps in toluene solution. A triplet quantum yield of 0.06 was measured using relative actinometry. Excited-state absorption cross sections of 5.6 X 10-17 cm2 (singlet) and 7.8 X 10-16 cm2 (triplet) at 532 nm were obtained by using a five-level dynamic model to fit open-aperture Z scans at picosecond and nanosecond pulse widths and a variety of pulse energies. Most significantly, fits of nanosecond transient difference absorption decay data yield a value of 16.3 µs for the triplet excited-state lifetime of the complex in deoxygenated toluene solution, longer by a factor of almost 20 than the lifetime of the analogous complex with benzothiazolylsubstituted ligands.

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