title: Energy level alignment and sub-bandgap charge generation in polymer:fullerene bulk heterojunction solar cells.
abstract: Using charge modulated electroabsorption spectroscopy (CMEAS), for the first time, the energy level alignment of a polymer:fullerene bulk heterojunction photovoltaic cell is directly measured. The charge-transfer excitons generated by the sub-bandgap optical pumping are coupled with the modulating electric field and introduce subtle changes in optical absorption in the sub-bandgap region. This minimum required energy for sub-bandgap charge genreation is defined as the effective bandgap.
authors: Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA.
authors: Sai-Wing
authors: SW
authors: Tsang
authors: Song
authors: S
authors: Chen
authors: Franky
authors: F
authors: So
mesh_terms: D011211:Electric Power Supplies; D004566:Electrodes; D004735:Energy Transfer; D004867:Equipment Design; D019544:Equipment Failure Analysis; D037741:Fullerenes / Q000737:chemistry*; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry*; D012993:Solar Energy; D055672:Static Electricity
chemical_list: D037741:Fullerenes; D011108:Polymers