Charge-carrier concentration dependence of the hopping mobility in organic materials with Gaussian disorder
- 26 October 2005
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 72 (15), 155206
- https://doi.org/10.1103/physrevb.72.155206
Abstract
It has recently been demonstrated that the hopping mobility in semiconducting organic materials depends on the charge-carrier concentration. We have analyzed this effect within the framework of six existing semianalytical models, for the case of a Gaussian density of states (DOS). These models were either not applied earlier to the case of a Gaussian DOS, or are shown to require a major modification. The mobility is constant below a certain concentration, which decreases with increasing ratio of the width of the DOS over the thermal energy , and it increases for larger concentrations. At very high concentrations final state effects limit this increase or even give rise to a decrease. An analytical expression is given for the mobility, , in the form of the product of the mobility in the low concentration limit times a concentration and -dependent enhancement factor. Depending on , varies approximately linearly with or with . This finding may lead to a solution for the long-standing controversy between polaron-based and disorder-based hopping models.
Keywords
This publication has 38 references indexed in Scilit:
- Wide Energy-Window View on the Density of States and Hole Mobility in Poly(-Phenylene Vinylene)Physical Review Letters, 2004
- Plastic Solar CellsAdvanced Functional Materials, 2001
- Charge transport in poly(p-phenylene vinylene) light-emitting diodesMaterials Science and Engineering: R: Reports, 2000
- Comparative study of hole transport in poly(p-phenylene vinylene) derivativesPhysical Review B, 2000
- Temperature- and field-dependent electron and hole mobilities in polymer light-emitting diodesApplied Physics Letters, 1999
- Electroluminescence in conjugated polymersNature, 1999
- Low-cost all-polymer integrated circuitsApplied Physics Letters, 1998
- Charge Transport in Disordered Organic Photoconductors a Monte Carlo Simulation StudyPhysica Status Solidi (b), 1993
- Observation of the transition from adiabatic to nonadiabatic small polaron hopping in a molecularly doped polymerPhysical Review Letters, 1990
- Transient Photoconductivity in Poly(N-vinylcarbazole)The Journal of Chemical Physics, 1970