Molecular and electronic structure at C 60: pentacene interfaces

摘要: Successful utilization of organic donor-acceptor systems for photovoltaic applications requires understanding factors controlling molecular and electronic structure at interfaces. We have used STM, STS, and photoemission to study the donor-acceptor system C 60: pentacene. At low coverage, C 60 deposited on a well-ordered pentacene bilayer structure on Ag (111) adsorbs in between two adjacent pentacene rows. Isolated C 60 molecules are easily observed at room temperature indicating that the mobility of C 60 on pentacene is significantly smaller than on metal surfaces. Some images of C 60 reveal structure that may indicate a preferred C 60 orientation. Electrostatic contributions to intermolecular interactions are discussed to help explain C 60 adsorption between pentacene molecules. With increasing coverage, C 60 forms linear chains, still locked to underlying pentacene rows. A further increase in …