Long-lifetime reverse saturable absorption in a bipyridyl platinum(II) complex bearing naphthalimidylethynyl-substituted fluorenylacetylide ligands

Authors

Timothy M. Pritchett, U.S. Army Research LaboratoryFollow
Michael J. Ferry, U.S. Army Research Laboratory
Andrew G. Mott, U.S. Army Research Laboratory
William Shensky III, U.S. Army Research Laboratory
Joy E. Haley, Air Force Research Laboratory
Rui Hui, North Dakota State University
Wenfang Sun, North Dakota State University

Date of this Version

2015

Citation

Optical Materials 39 (2015)

Comments

U S. Government work.

Abstract

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.