|Donor-Acceptor Interfaces in Molecular Semiconductors: STM/STS Insights |
Chemistry and Chemical Biology
|Janice Reutt-Robey, University of Maryland.|
11:00 AM, Chem-WL Aud
The most efficient small-molecule organic solar cells to date employ heterojunctions between donor and acceptor materials. In principle, nanophase-separated donor-acceptor molecular film architectures will push the performance of such devices into a regime of cost-effective power generation. To realize this efficiency, a predictive understanding of the morphologies of binary molecular films, and their relationship to electronic band alignment, is needed. We show how the chemical morphology of binary molecular films can be manipulated via single-component phases on samples grown by PVD methods. We describe UHV-STM structural investigations on technologically relevant molecular films based upon C60 ,pentacene, and metal phthalocyanines. Binary film structures ranging from nano-phase segregation to co-crystalline phases,are generated. The electrostatic forces that stabilize such molecular architectures are described. Finally, the influence of chemical morphology on the electronic "conductance gap" is demonstrated with scanning tunneling spectroscopy.