A quantitative analytical model for static dipolar disorder broadening of the density of states at organic heterointerfaces

Richards, Tim; Bird, Matthew J.; Sirringhaus, Henning

doi:10.1063/1.2937729

Cited by 121 publications

(115 citation statements)

References 17 publications

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“…In another paper the same authors showed that for 235302-4 a poly(triarylamine) (PTAA) OFET the slope of the mobility versus gate bias curve depends on temperature. 17 After an initial steep rise at low gate bias, the mobility decreases with increasing gate bias at 300 K, whereas it continues to increase at 170 K. Again, such behavior is anticipated for intermediate disorder strength.…”

Section: Resultsmentioning

confidence: 82%

Dimensionality of charge transport in organic field-effect transistors

et al. 2012

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Application of a gate bias to an organic field-effect transistor leads to accumulation of charges in the organic semiconductor within a thin region near the gate dielectric. An important question is whether the charge transport in this region can be considered two-dimensional, or whether the possibility of charge motion in the third dimension, perpendicular to the accumulation layer, plays a crucial role. In order to answer this question we have performed Monte Carlo simulations of charge transport in organic field-effect transistor structures with varying thickness of the organic layer, taking into account all effects of energetic disorder and Coulomb interactions. We show that with increasing thickness of the semiconductor layer the source-drain current monotonically increases for weak disorder, whereas for strong disorder the current first increases and then decreases. Similarly, for a fixed layer thickness the mobility may either increase or decrease with increasing gate bias. We explain these results by the enhanced effect of state filling on the current for strong disorder, which competes with the effects of Coulomb interactions and charge motion in the third dimension. Our conclusion is that apart from the situation of a single monolayer, charge transport in an organic semiconductor layer should be considered three-dimensional, even at high gate bias.

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Section: Resultsmentioning

confidence: 82%

Dimensionality of charge transport in organic field-effect transistors

et al. 2012

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“…Here charge motion is not only related to the intrinsic properties of the semiconductor layer but also to processes taking place at the organic-dielectric interface. For example, Fröhlich polarons form in devices fabricated on high-k inorganic dielectrics (strong coupling regime) (19,24), and broadening of the density of states occurs due to static dipolar disorder in devices with polymeric dielectrics (weak coupling) (25,26). As a consequence, the charges become localized, their mobility is reduced, and, in some cases, depending on the strength of the coupling, the transport becomes thermally activated.…”

Section: Significancementioning

confidence: 99%

Crossover from band-like to thermally activated charge transport in organic transistors due to strain-induced traps

Mei

Diemer

Niazi

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…In the static limit, the polarization acts instead as an additional source of disorder, due to the random arrangement of charged dipoles in the substrate. [55,25] Both effects can convert the "bandlike" temperature dependent mobility intrinsic to organic semiconductors into a thermally activated behavior, and will not be considered here.…”

Section: Molecularmentioning

confidence: 99%

The Transient Localization Scenario for Charge Transport in Crystalline Organic Materials

Fratini

Mayou

Ciuchi

2016

Adv Funct Materials

338

452

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Charge transport in crystalline organic semiconductors is intrinsically limited by the presence of large thermal molecular motions, which are a direct consequence of the weak van der Waals inter-molecular interactions. These lead to an original regime of transport called transient localization, sharing features of both localized and itinerant electron systems. After a brief review of experimental observations that pose a challenge to the theory, we concentrate on a commonly studied model which describes the interaction of the charge carriers with inter-molecular vibrations. We present different theoretical approaches that have been applied to the problem in the past, and then turn to more modern approaches that are able to capture the key microscopic phenomenon at the origin of the puzzling experimental observations, i.e. the quantum localization of the electronic wavefuntion at timescales shorter than the typical molecular motions. We describe in particular a relaxation time approximation which clarifies how the transient localization due to dynamical molecular motions relates to the Anderson localization realized for static disorder, and allows us to devise strategies to improve the mobility of actual compounds. The relevance of the transient localization scenario to other classes of systems is briefly discussed.

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A quantitative analytical model for static dipolar disorder broadening of the density of states at organic heterointerfaces

Cited by 121 publications

References 17 publications

Dimensionality of charge transport in organic field-effect transistors

Dimensionality of charge transport in organic field-effect transistors

Crossover from band-like to thermally activated charge transport in organic transistors due to strain-induced traps

The Transient Localization Scenario for Charge Transport in Crystalline Organic Materials

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