title: Organometallic dimers: application to work-function reduction of conducting oxides.
abstract: The dimers of pentamethyliridocene and ruthenium pentamethylcyclopentadienyl mesitylene, (IrCp*Cp)2 and (RuCp*mes)2, respectively, are shown here to be effective solution-processable reagents for lowering the work functions of electrode materials; this approach is compared to the use of solution-deposited films of ethoxylated poly(ethylenimine) (PEIE). The work functions of indium tin oxide (ITO), zinc oxide, and gold electrodes can be reduced to 3.3-3.4 eV by immersion in a toluene solution of (IrCp*Cp)2; these values are similar to those that can be obtained by spin-coating a thin layer of PEIE onto the electrodes. The work-function reductions achieved using (IrCp*Cp)2 are primarily attributable to the interface dipoles associated with the formation of submonolayers of IrCp*Cp(+) cations on negatively charged substrates, which in turn result from redox reactions between the dimer and the electrode. The electrical properties of C60 diodes with dimer-modified ITO cathodes are similar to those of analogous devices with PEIE-modified ITO cathodes.
authors: School of Chemistry and Biochemistry and ‡School of Electrical and Computer Engineering, Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States.
authors: Anthony J
authors: AJ
authors: Giordano
authors: Federico
authors: F
authors: Pulvirenti
authors: Talha M
authors: TM
authors: Khan
authors: Canek
authors: C
authors: Fuentes-Hernandez
authors: Karttikay
authors: K
authors: Moudgil
authors: Jared H
authors: JH
authors: Delcamp
authors: Bernard
authors: B
authors: Kippelen
authors: Stephen
authors: S
authors: Barlow
authors: Seth R
authors: SR
authors: Marder
keywords: dopant; electron injection; indium tin oxide; iridocene; poly(ethylenimine); work function