10.1021/jacs.5b08770.s001
Carlito S. Ponseca
Carlito S.
Ponseca
Eline M. Hutter
Eline M.
Hutter
Piotr Piatkowski
Piotr
Piatkowski
Boiko Cohen
Boiko
Cohen
Torbjörn Pascher
Torbjörn
Pascher
Abderrazzak Douhal
Abderrazzak
Douhal
Arkady Yartsev
Arkady
Yartsev
Villy Sundström
Villy
Sundström
Tom J. Savenije
Tom J.
Savenije
Mechanism
of Charge Transfer and Recombination Dynamics
in Organo Metal Halide Perovskites and Organic Electrodes, PCBM, and
Spiro-OMeTAD: Role of Dark Carriers
American Chemical Society
2015
MAPbI 3.
decay
electron
electrode
PCBM
subpicosecond time scale
interface
doping
injection
charge transfer dynamics
concentration
perovskite
Organo Metal Halide Perovskites
recombination
2015-12-30 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Mechanism_of_Charge_Transfer_and_Recombination_Dynamics_in_Organo_Metal_Halide_Perovskites_and_Organic_Electrodes_PCBM_and_Spiro_OMeTAD_Role_of_Dark_Carriers/2093875
Despite the unprecedented interest
in organic–inorganic
metal halide perovskite solar cells, quantitative information on the
charge transfer dynamics into selective electrodes is still lacking.
In this paper, we report the time scales and mechanisms of electron
and hole injection and recombination dynamics at organic PCBM and
Spiro-OMeTAD electrode interfaces. On the one hand, hole transfer
is complete on the subpicosecond time scale in MAPbI<sub>3</sub>/Spiro-OMeTAD,
and its recombination rate is similar to that in neat MAPbI<sub>3</sub>. This was found to be due to a high concentration of dark charges,
i.e., holes brought about by unintentional p-type doping of MAPbI<sub>3</sub>. Hence, the total concentration of holes in the perovskite
is hardly affected by optical excitation, which manifested as similar
decay kinetics. On the other hand, the decay of the photoinduced conductivity
in MAPbI<sub>3</sub>/PCBM is on the time scale of hundreds of picoseconds
to several nanoseconds, due to electron injection into PCBM and electron–hole
recombination at the interface occurring at similar rates. These results
highlight the importance of understanding the role of dark carriers
in deconvoluting the complex photophysical processes in these materials.
Moreover, optimizing the preparation processes wherein undesired doping
is minimized could prompt the use of organic molecules as a more viable
electrode substitute for perovskite solar cell devices.