Collecting the Electrons on n-Doped Fullerene C_(60) Transparent Conductors for All-Vacuum-Deposited Small-Molecule Organic Solar Cells

摘要

The development of novel transparent electrodes is of great importance for realizing low-cost, flexible, and efficient organic photovoltaic (OPV) cells. Currently, indium tin oxide (ITO) is the market standard electrode for most organic optoelectronic devices and OPV cells due to its high conductivity, high trans-mittance, and reliable throughput. However, ITO significantly increases device costs due to the high material costs and its inherent brittleness limits application in flexible devices. In this respect, the replacement of ITO is of major interest for OPV cells and organic light-emitting diodes (OLEDs) applications. Among many alternative electrodes, pure carbon-based nanomaterials such as graphene and carbon nanotubes (CNTs) have recently attracted a great deal of attention due to its material abundance and unique electrical, optical, and physical properties.However, the device efficiencies based on graphene and CNT electrodes have still not reached that of ITO-based OPV cells because of rather high sheet resistances of the electrode films resulting from non-uniform surface morphology and partially poor crystal quality of graphene, or high tube-tube contact resistances of CNTs.