Low-field charge-carrier hopping transport in energetically and positionally disordered organic materials -: art. no. 245212

被引:42
作者
Fishchuk, II
Kadashchuk, A
Bässler, H
Abkowitz, M
机构
[1] Natl Acad Sci Ukraine, Inst Nucl Res, UA-03680 Kiev, Ukraine
[2] Tech Univ Darmstadt, Inst Mat Sci, Darmstadt, Germany
[3] Natl Acad Sci Ukraine, Inst Phys, UA-03028 Kiev, Ukraine
[4] Univ Marburg, Inst Phys Nucl & Macromol Chem, D-35032 Marburg, Germany
[5] Univ Marburg, Ctr Mat Sci, D-35032 Marburg, Germany
[6] Enabling Technol, Webster, NY 14580 USA
[7] Univ Rochester, Dept Chem, Rochester, NY 14627 USA
关键词
D O I
10.1103/PhysRevB.70.245212
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
The influence of superimposed energetic and positional disorder on the field dependence of drift mobility in disordered organic solids is considered for the first time analytically by an effective medium theory using jump rate expressions based either on Miller-Abrahams or Marcus models. We find that the negative field dependence of drift mobility at low fields is a genuine property of the hopping transport in disordered solids rather than an artifact and it can be theoretically reproduced for certain parameters of the investigated material and specific measurement conditions. We demonstrate that the recently suggested influence of the diffusion-controlled transport at low fields on the measured time-of-flight mobility plays no role in explaining the observed phenomena. Furthermore the frequently used practice of extrapolating field dependence of mobility to zero field has no theoretical justification. The results of the calculations are found to be in good agreement with both appropriate computer simulations and experimental results.
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页码:1 / 12
页数:12
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