11176
J. Phys. Chem. B 1999, 103, 11176-11180
Electron Injection Dynamics of RuII(4,4′-dicarboxy-2,2′-bipyridine)2cis(NCS)2 Adsorbed on MoS2 Nanoclusters B. T. Langdon,† V. J. MacKenzie,† D. J. Asunskis,‡ and D. F. Kelley*,†,‡ Department of Chemistry, Colorado State UniVersity, Fort Collins, Colorado 80523-1872, and Department of Chemistry, Kansas State UniVersity, Manhattan, Kansas 66506-3701 ReceiVed: August 31, 1999
The electron injection dynamics of RuII(4,4′-dicarboxy-2,2′-bipyridine)2cis(NCS)2 (N3 dye) adsorbed on MoS2 nanoclusters have been studied using static and time-resolved optical spectroscopy. Static spectroscopy and the comparison with RuII(2,2′-bipyridine)2cis(NCS)2 indicate that the N3 is bound to the MoS2 nanoclusters and that the binding occurs through the carboxylates. The static absorption spectrum of adsorbed N3/MoS2 is red shifted about 1.2 nm compared to N3 in an equivalent acetonitrile/hexanol/tridodecylmethylammonium iodide solution. The extent of the spectral shift indicates that the coupling is comparable to that in the N3/ TiO2 case. The time-resolved results indicate that about 35% of the adsorbed dyes inject electrons into the MoS2 conduction band on the 250 ps time scale, and about 65% do not inject. These results indicate that electron injection is comparatively slow in these systems (250 ps compared to
