TY  - JOUR
A1  - Pingel, Patrick
A1  - Arvind, Malavika
A1  - Kölln, Lisa
A1  - Steyrleuthner, Robert
A1  - Kraffert, Felix
A1  - Behrends, Jan
A1  - Janietz, Silvia
A1  - Neher, Dieter
T1  - p-Type Doping of Poly(3-hexylthiophene) with the Strong Lewis Acid Tris(pentafluorophenyl)borane
JF  - Advanced electronic materials
N2  - State-of-the-art p-type doping of organic semiconductors is usually achieved by employing strong -electron acceptors, a prominent example being tetrafluorotetracyanoquinodimethane (F(4)TCNQ). Here, doping of the semiconducting model polymer poly(3-hexylthiophene), P3HT, using the strong Lewis acid tris(pentafluorophenyl)borane (BCF) as a dopant, is investigated by admittance, conductivity, and electron paramagnetic resonance measurements. The electrical characteristics of BCF- and F(4)TCNQ-doped P3HT layers are shown to be very similar in terms of the mobile hole density and the doping efficiency. Roughly 18% of the employed dopants create mobile holes in either F-4 TCNQ- or BCF-doped P3HT, while the majority of doping-induced holes remain strongly Coulomb-bound to the dopant anions. Despite similar hole densities, conductivity and hole mobility are higher in BCF-doped P3HT layers than in F(4)TCNQ-doped samples. This and the good solubility in many organic solvents render BCF very useful for p-type doping of organic semiconductors.
KW  - charge carrier transport
KW  - charge transfer
KW  - conductivity
KW  - molecular doping
KW  - organic semiconductors
Y1  - 2016
U6  - https://doi.org/10.1002/aelm.201600204
SN  - 2199-160X
VL  - 2
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Schubert, Marcel
A1  - Collins, Brian A.
A1  - Mangold, Hannah
A1  - Howard, Ian A.
A1  - Schindler, Wolfram
A1  - Vandewal, Koen
A1  - Roland, Steffen
A1  - Behrends, Jan
A1  - Kraffert, Felix
A1  - Steyrleuthner, Robert
A1  - Chen, Zhihua
A1  - Fostiropoulos, Konstantinos
A1  - Bittl, Robert
A1  - Salleo, Alberto
A1  - Facchetti, Antonio
A1  - Laquai, Frederic
A1  - Ade, Harald W.
A1  - Neher, Dieter
T1  - Correlated donor/acceptor crystal orientation controls photocurrent generation in all-polymer solar cells
JF  - Advanced functional materials
N2  - New polymers with high electron mobilities have spurred research in organic solar cells using polymeric rather than fullerene acceptors due to their potential of increased diversity, stability, and scalability. However, all-polymer solar cells have struggled to keep up with the steadily increasing power conversion efficiency of polymer: fullerene cells. The lack of knowledge about the dominant recombination process as well as the missing concluding picture on the role of the semi-crystalline microstructure of conjugated polymers in the free charge carrier generation process impede a systematic optimization of all-polymer solar cells. These issues are examined by combining structural and photo-physical characterization on a series of poly(3-hexylthiophene) (donor) and P(NDI2OD-T2) (acceptor) blend devices. These experiments reveal that geminate recombination is the major loss channel for photo-excited charge carriers. Advanced X-ray and electron-based studies reveal the effect of chloronaphthalene co-solvent in reducing domain size, altering domain purity, and reorienting the acceptor polymer crystals to be coincident with those of the donor. This reorientation correlates well with the increased photocurrent from these devices. Thus, effi cient split-up of geminate pairs at polymer/polymer interfaces may necessitate correlated donor/acceptor crystal orientation, which represents an additional requirement compared to the isotropic fullerene acceptors.
Y1  - 2014
U6  - https://doi.org/10.1002/adfm.201304216
SN  - 1616-301X
SN  - 1616-3028
VL  - 24
IS  - 26
SP  - 4068
EP  - 4081
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Kraffert, Felix
A1  - Steyrleuthner, Robert
A1  - Albrecht, Steve
A1  - Neher, Dieter
A1  - Scharber, Markus C.
A1  - Bittl, Robert
A1  - Behrends, Jan
T1  - Charge Separation in PCPDTBT : PCBM Blends from an EPR Perspective
JF  - The journal of physical chemistry
Y1  - 2014
U6  - https://doi.org/10.1021/jp509650v
SN  - 1932-7447
VL  - 118
IS  - 49
SP  - 28482
EP  - 28493
PB  - American Chemical Society
CY  - Washington
ER  -