title: Carbazole Dye-Sensitized Solar Cells Studied from Femtoseconds to Seconds-Effect of Additives in Cobalt- and Iodide-Based Electrolytes.
abstract: Comprehensive studies of all charge-separation processes in efficient carbazole dye-sensitized solar cells are correlated with their photovoltaic parameters. An important role of partial, fast electron recombination from the semiconductor nanoparticles to the oxidized dye is revealed; this takes place on the picosecond and sub-nanosecond timescales. The charge-transfer dynamics in cobalt tris(bipyridyl) based electrolytes and iodide-based electrolyte is observed to depend on potential-determining additives in a similar way. Upon addition of 0.5 M 4-tert-butylpiridine to both types of electrolytes, the stability of the cells is greatly improved; the cell photovoltage increases by 150-200 mV, the electron injection rate decreases about five times (from 5 to 1 ps(-1) ), and fast recombination slows down about two to three times. Dye regeneration proceeds at a rate of about 1 μs(-1) in all electrolytes. Electron recombination from titania to cobalt electrolytes is much faster than that to iodide ones.
authors.affiliation: NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan (Poland).|Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan (Poland).
authors.forename: Jan
authors.initials: J
authors.lastname: Sobuś
authors.affiliation: Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan (Poland).
authors.forename: Jacek
authors.initials: J
authors.lastname: Kubicki
authors.affiliation: Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan (Poland).
authors.forename: Gotard
authors.initials: G
authors.lastname: Burdziński
authors.affiliation: Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan (Poland). marziol@amu.edu.pl.
authors.forename: Marcin
authors.initials: M
authors.lastname: Ziółek
mesh_terms: D065966:Absorption, Physicochemical; D002227:Carbazoles / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D011211:Electric Power Supplies; D004573:Electrolytes / Q000737:chemistry; D007454:Iodides / Q000737:chemistry*; D007700:Kinetics; D010084:Oxidation-Reduction; D012993:Solar Energy
chemical_list: D002227:Carbazoles; D004396:Coloring Agents; D004573:Electrolytes; D007454:Iodides; C041514:carbazole; D003035:Cobalt
keywords: cobalt; dyes/pigments; iodine; laser spectroscopy; solar cells