Geminate charge recombination in alternating polyfluorene copolymer/fullerene blends.
By measuring excited state and charge dynamics in blends of an alternating polyfluorene copolymer and fullerene derivative over nine orders in time and two orders in light intensity, we have monitored the light-induced processes from ultrafast charge photogeneration to much slower decay of charges by recombination. We find that at low light intensities relevant to solar cell operation relatively fast (approximately 30 ns) geminate recombination is the dominating charge decay process, while nongeminate recombination has a negligible contribution. The conclusion of our work is that under solar illumination conditions geminate recombination of charges may be directly competing with efficient charge collection in polymer/fullerene solar cells.
De
Swati
S
Chemical Physics, Lund University, PO Box 124, SE-22100 Lund, Sweden.
Pascher
Torbjörn
T
Maiti
Manisankar
M
Jespersen
Kim G
KG
Kesti
Tero
T
Zhang
Fengling
F
Inganäs
Olle
O
Yartsev
Arkady
A
Sundström
Villy
V
D005449:Fluorenes / Q000737:chemistry*; D037741:Fullerenes / Q000737:chemistry*
D005449:Fluorenes; D037741:Fullerenes