Toward Functional Inorganic/Organic Hybrids: Phenoxy-allyl-PTCDI Synthesis, Experimentally and Theoretically Determined Properties of the Isolated Molecule, Layer Characteristics, and the Interface Formation of Phenoxy-allyl-PTCDI on Si(111):H Determined by SXPS and DFT

• Published in: Journal of physical chemistry. C 2011-11, Vol.115 (43), p.21139-21150
• Main Authors: Decker, Andreas, Suraru, Sabin-Lucian, Rubio-Pons, Oscar, Mankel, Eric, Bockstedte, Michel, Thoss, Michael, Würthner, Frank, Mayer, Thomas, Jaegermann, Wolfram
• Format: Article
• Language: English
• Subjects: C: Surfaces, Interfaces, Catalysis
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp205294h

A new perylene diimide derivative, namely N,N′-diallyl-1,6,7,12-tetraphenoxyperylene-3,4:9,10-tetracarboxylic acid diimide (phenoxy-allyl-PTCDI, abbreviated PA-PTCDI), is introduced. The investigations presented in this paper aim at finding a molecule for use as a sensitzer in thin film silicon solar cells in order to enhance efficiency. The synthesis is described along with optical and electrochemical measurements of PA-PTCDI in solution. A good agreement is found between the measured data and theoretical calculations. The molecule is characterized further by optical and photoemission data on thin films, which also show that the dye can be sublimed in vacuum. The interface between the dye and silicon is investigated on the model system Si(111):H with synchrotron-induced photoemission spectroscopy. The result is an electronic lineup with the gap centers of silicon and PA-PTCDI almost at identical positions and thus very similar band discontinuities from the lowest unoccupied molecular orbital (LUMO) to the conduction band as well as from the highest occupied molecular orbital (HOMO) to the valence band. This clearly permits a transfer of photogenerated electrons and holes from PA-PTCDI to silicon. The experimental valence band discontinuity matches very well the value calculated for a very similar PTCDI molecule.