High-Extinction Ruthenium Compounds for Sunlight Harvesting and Hole Transport
Abstract
The compounds Ru(bpy)2(BTL)(PF6)2 and Ru(deeb)2(BTL)(PF6)2, where bpy is 2,2(prime)-bipyridine, deeb is 4,4(prime)-(C2H5CO2)2-bpy, and BTL is 9(prime)-[4,5-bis(cyanoethylthio)]-1,3-dithiol-2-ylidene]-4(prime),5(prime)-diazafluorene, were found to have very high extinction coefficients in the visible region. In an acetonitrile solution, the extinction of Ru(deeb)2(BTL)(PF6)2 was epsilon = 44 000 plus/minus 1000 M(exp -1) cm(exp )-1 at lambda = 470 nm. Two quasi-reversible oxidation waves, E(sub 1/2) = +0.88 and +1.16 V, and an irreversible reduction, E(sub pr) = -1.6 V, were observed versus ferrocene (Fc(exp +/0)). At -40 degrees Celsius, a state was observed with spectroscopic properties characteristic of a metal-to-ligand charge-transfer excited state, tau = 25 ns. This same compound was found to photoinject electrons into TiO2 with a quantum yield phi = 0.3 plus/minus 0.2 for 532.5 or 417 nm light excitation in a 0.1 M LiClO4/acetonitrile electrolyte. In regenerative solar cells, a sustained photocurrent was observed with a maximum incident photon-to-current efficiency of 0.4. The photocurrent action and absorptance spectra were in good agreement, consistent with injection from a single excited state.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 29, 2008
- Accession Number
- ADA519170
Entities
People
- Aaron Staniszewski
- Gerald Meyer
- William B. Heuer