2 research outputs found
Quantitative Analysis of the Molecular Dynamics of P3HT:PCBM Bulk Heterojunction
The
optoelectronic properties of blends of conjugated polymers
and small molecules are likely to be affected by the molecular dynamics
of the active layer components. We study the dynamics of regioregular
polyÂ(3-hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester
(PCBM) blends using molecular dynamics (MD) simulation on time scales
up to 50 ns and in a temperature range of 250–360 K. First,
we compare the MD results with quasi-elastic neutron-scattering (QENS)
measurements. Experiment and simulation give evidence of the vitrification
of P3HT upon blending and the plasticization of PCBM by P3HT. Second,
we reconstruct the QENS signal based on the independent simulations
of the three phases constituting the complex microstructure of such
blends. Finally, we found that P3HT chains tend to wrap around PCBM
molecules in the amorphous mixture of P3HT and PCBM; this molecular
interaction between P3HT and PCBM is likely to be responsible for
the observed frustration of P3HT, the plasticization of PCBM, and
the partial miscibility of P3HT and PCBM
New Insights into the Molecular Dynamics of P3HT:PCBM Bulk Heterojunction: A Time-of-Flight Quasi-Elastic Neutron Scattering Study
The
molecular dynamics of organic semiconductor blend layers are
likely to affect the optoelectronic properties and the performance
of devices such as solar cells. We study the dynamics (5–50
ps) of the polyÂ(3-hexylthiophene) (P3HT): phenyl-C61-butyric acid
methyl ester (PCBM) blend by time-of-flight quasi-elastic neutron
scattering, at temperatures in the range 250–360 K, thus spanning
the glass transition temperature region of the polymer and the operation
temperature of an OPV device. The behavior of the QENS signal provides
evidence for the vitrification of P3HT upon blending, especially above
the glass transition temperature, and the plasticization of PCBM by
P3HT, both dynamics occurring on the picosecond time scale