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  - Turner, Sarah T.
A1  - Pingel, Patrick
A1  - Steyrleuthner, Robert
A1  - Crossland, Edward J. W.
A1  - Ludwigs, Sabine
A1  - Neher, Dieter
T1  - Quantitative analysis of bulk heterojunction films using linear absorption spectroscopy and solar cell performance
JF  - Advanced functional materials
N2  - A fundamental understanding of the relationship between the bulk morphology and device performance is required for the further development of bulk heterojunction organic solar cells. Here, non-optimized (chloroform cast) and nearly optimized (solvent-annealed o-dichlorobenzene cast) P3HT:PCBM blend films treated over a range of annealing temperatures are studied via optical and photovoltaic device measurements. Parameters related to the P3HT aggregate morphology in the blend are obtained through a recently established analytical model developed by F. C. Spano for the absorption of weakly interacting H-aggregates. Thermally induced changes are related to the glass transition range of the blend. In the chloroform prepared devices, the improvement in device efficiency upon annealing within the glass transition range can be attributed to the growth of P3HT aggregates, an overall increase in the percentage of chain crystallinity, and a concurrent increase in the hole mobilities. Films treated above the glass transition range show an increase in efficiency and fill factor not only associated with the change in chain crystallinity, but also with a decrease in the energetic disorder. On the other hand, the properties of the P3HT phase in the solvent-annealed o-dichlorobenzene cast blends are almost indistinguishable from those of the corresponding pristine P3HT layer and are only weakly affected by thermal annealing. Apparently, slow drying of the blend allows the P3HT chains to crystallize into large domains with low degrees of intra- and interchain disorder. This morphology appears to be most favorable for the efficient generation and extraction of charges.
KW  - Organic electronics
KW  - morphology
KW  - solar cells
KW  - mobility
KW  - absorption spectroscopy
Y1  - 2011
U6  - https://doi.org/10.1002/adfm.201101583
SN  - 1616-301X
VL  - 21
IS  - 24
SP  - 4640
EP  - 4652
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Pingel, Patrick
A1  - Zen, Achmad
A1  - Neher, Dieter
A1  - Lieberwirth, Ingo
A1  - Wegner, Gerhard
A1  - Allard, Sybille
A1  - Scherf, Ullrich
T1  - Unexpectedly high field-effect mobility of a soluble, low molecular weight oligoquaterthiophene fraction with low polydispersity
N2  - Layers made from soluble low molecular weight polythiophene PQT-12 with low polydispersity exhibit a highly ordered structure and charge-carrier mobilities of the order of 10(-3) cm(2)/(V s), which we attribute to its proximity to monodispersity. We propose that polydispersity is a decisive factor with regard to structure formation and transport properties of soluble low molecular weight polythiophenes.
Y1  - 2009
UR  - http://www.springerlink.com/content/100501
U6  - https://doi.org/10.1007/s00339-008-4994-0
SN  - 0947-8396
ER  -