Negative electric field dependence of charge carrier drift mobility in conjugated, semiconducting polymers

The temperature and electric field dependence of the hole mobility in regioregular poly(3-hexylthiophene) (P3HT) is studied by time-of-flight (TOF) technique. It is observed that above � 250 K the slope of the electric field dependence of mobility becomes negative. Such phenomenon has been reported previously for a variety of amorphous charge transport materials, but not clearly observed in conjugated semiconducting polymers. The temperature and electric field dependence of mobility is analyzed both in the framework of Gill’s phenomenological data analysis and disorder formalism. The occurrence of negative field dependence in the measured regioregular P3HT samples is attributed to the small energetic (r ¼ 70 meV), but large spatial disorder ðR ¼ 3:4Þ. 2004 Elsevier B.V. All rights reserved.

[1]  Y. Shirota,et al.  Negative electric-field dependence of hole drift mobility for a molecular glass of tri(o-terphenyl-4-yl)amine , 1997 .

[2]  Paul M. Borsenberger,et al.  Organic photoreceptors for xerography , 1998 .

[3]  H. Bässler,et al.  Hole transport in polyphenylenevinylene-ether under bulk photoexcitation and sensitized injection , 2000 .

[4]  E. Abrahams,et al.  Impurity Conduction at Low Concentrations , 1960 .

[5]  H. Bässler,et al.  Anomalous Field Dependence of the Hole Mobility in a Molecular Doped Polymer , 1993 .

[6]  G. Hadziioannou,et al.  Semiconducting polymers: chemistry, physics and engineering , 2005 .

[7]  N. V. Lien,et al.  Hopping conduction in strong electric fields and directed percolation , 1981 .

[8]  M. Abkowitz,et al.  Hopping transport in prototypical organic glasses , 1982 .

[9]  M. Rikukawa,et al.  Photocarrier Mobility in Regioregular Poly(3-hexylthiophene) Studied by the Time of Flight Method , 1999 .

[10]  H. Bässler.  Charge Transport in Disordered Organic Photoconductors a Monte Carlo Simulation Study , 1993 .

[11]  P. Blom,et al.  Electric-field and temperature dependence of the hole mobility in poly(p-phenylene vinylene) , 1997 .

[12]  E. I. Levin,et al.  Negative differential conductivity of low density electron gas in random potential , 1988 .

[13]  P. Blom,et al.  Comparative study of hole transport in poly(p-phenylene vinylene) derivatives , 2000 .

[14]  A. Kadavanich,et al.  Effects of impurities on the optical properties of poly-3-hexylthiophene thin films , 2002 .

[15]  Borsenberger,et al.  Nondispersive-to-dispersive charge-transport transition in disordered molecular solids. , 1992, Physical review. B, Condensed matter.

[16]  T. Endo,et al.  Regioregularity vs Regiorandomness: Effect on Photocarrier Transport in Poly(3-hexylthiophene) , 2000 .

[17]  Dunlap,et al.  Charge-Dipole Model for the Universal Field Dependence of Mobilities in Molecularly Doped Polymers. , 1996, Physical review letters.

[18]  R. Österbacka,et al.  Charge transport at low electric fields in π -conjugated polymers , 2002 .

[19]  C. Brabec,et al.  Plastic Solar Cells , 2001 .

[20]  W. D. Gill.  Drift mobilities in amorphous charge‐transfer complexes of trinitrofluorenone and poly‐n‐vinylcarbazole , 1972 .

[21]  Y. Shirota.  Organic materials for electronic and optoelectronic devices , 2000 .

[22]  J. Kǒcka,et al.  Extraction current transients: new method of study of charge transport in microcrystalline silicon , 2000, Physical review letters.

[23]  Meyer,et al.  Trap distribution for charge carriers in poly(paraphenylene vinylene) (PPV) and its substituted derivative DPOP-PPV. , 1995, Physical review. B, Condensed matter.

[24]  W. R. Salaneck,et al.  Electroluminescence in conjugated polymers , 1999, Nature.

[25]  P. Borsenberger.  Hole transport in mixtures of 1,1-bis(di-4-tolylaminophenyl) cyclohexane and bisphenol-A-polycarbonate , 1990 .

[26]  L. Schein,et al.  Hole mobilities that decrease with increasing electric fields in a molecularly doped polymer , 1988 .

[27]  C. Dimitrakopoulos,et al.  Organic Thin Film Transistors for Large Area Electronics , 2002 .

[28]  Borsenberger,et al.  Dispersive and nondispersive charge transport in a molecularly doped polymer with superimposed energetic and positional disorder. , 1993, Physical review. B, Condensed matter.