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

Document Type

Article

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.