We demonstrate the effect of the selective introduction of gold catalytic sites on CdSe@CdSe nanorods on the frontier orbital energies and kinetics of charge transfer processes using waveguide spectroelectrochemistry and photoemission spectroscopy.  Reversible electron injection into spin-coated submonolayers of CdSe@CdSe nanorods, Au-CdSe@CdSe rods and welded Au-CdSe@CdSe rods on indium tin oxide (ITO) substrates was observed. The conduction band edge was estimated for each heterostructure by measuring the onset potential for the optical bleaching of the first excitonic peak. The ionization potential (IP) and interface dipole effects of the above hybrid materials were characterized using He(I) and He(II) UV photoemission spectroscopy (UPS). Changes in the conduction band, valence band and local vacuum level work function were observed upon tipping of CdSe nanorods with gold. Approximately 50-100 meV conduction band shifts closer to local vacuum level were revealed by spectroelectrochemistry. Potential-modulated attenuated total reflectance (PM-ATR) was utilized to measure the apparent heterogeneous rate constants of reversible electron injection processes.  The rate constants for Au-CdSe nanorod hybrid structures were found to be higher than that of the untipped CdSe@CdSe nanorods. The importance of characterizing frontier orbital energies and kinetic parameters of hybrid materials for future development of photoelectrochemical devices is discussed.

Waveguide spectroelectrochemical and photoemission spectroscopic characterization of frontier orbital energies and charge injection processes in Au-CdSe hybrid nanostructures

248th National Meeting (2014)

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