TY - JOUR
T1 - The Impact of Donor-Acceptor Phase Separation on the Charge Carrier Dynamics in pBTTT:PCBM Photovoltaic Blends
AU - Gehrig, Dominik W.
AU - Howard, Ian A.
AU - Sweetnam, Sean
AU - Burke, Timothy M.
AU - McGehee, Michael D.
AU - Laquai, Frédéric
N1 - KAUST Repository Item: Exported on 2020-10-01
PY - 2015/4/7
Y1 - 2015/4/7
N2 - The effect of donor–acceptor phase separation, controlled by the donor–acceptor mixing ratio, on the charge generation and recombination dynamics in pBTTT-C14:PC70BM bulk heterojunction photovoltaic blends is presented. Transient absorption (TA) spectroscopy spanning the dynamic range from pico- to microseconds in the visible and near-infrared spectral regions reveals that in a 1:1 blend exciton dissociation is ultrafast; however, charges cannot entirely escape their mutual Coulomb attraction and thus predominantly recombine geminately on a sub-ns timescale. In contrast, a polymer:fullerene mixing ratio of 1:4 facilitates the formation of spatially separated, that is free, charges and reduces substantially the fraction of geminate charge recombination, in turn leading to much more efficient photovoltaic devices. This illustrates that spatially extended donor or acceptor domains are required for the separation of charges on an ultrafast timescale (
AB - The effect of donor–acceptor phase separation, controlled by the donor–acceptor mixing ratio, on the charge generation and recombination dynamics in pBTTT-C14:PC70BM bulk heterojunction photovoltaic blends is presented. Transient absorption (TA) spectroscopy spanning the dynamic range from pico- to microseconds in the visible and near-infrared spectral regions reveals that in a 1:1 blend exciton dissociation is ultrafast; however, charges cannot entirely escape their mutual Coulomb attraction and thus predominantly recombine geminately on a sub-ns timescale. In contrast, a polymer:fullerene mixing ratio of 1:4 facilitates the formation of spatially separated, that is free, charges and reduces substantially the fraction of geminate charge recombination, in turn leading to much more efficient photovoltaic devices. This illustrates that spatially extended donor or acceptor domains are required for the separation of charges on an ultrafast timescale (
UR - http://hdl.handle.net/10754/553017
UR - http://doi.wiley.com/10.1002/marc.201500112
UR - http://www.scopus.com/inward/record.url?scp=84930377802&partnerID=8YFLogxK
U2 - 10.1002/marc.201500112
DO - 10.1002/marc.201500112
M3 - Article
SN - 1022-1336
VL - 36
SP - 1054
EP - 1060
JO - Macromolecular Rapid Communications
JF - Macromolecular Rapid Communications
IS - 11
ER -
