Nondispersive polaron transport in disordered organic solids

Fishchuk, I. I.; Kadashchuk, A.; Bäßler, H.; Nešpůrek, S.

doi:10.1103/physrevb.67.224303

Cited by 100 publications

(86 citation statements)

References 32 publications

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“…(PBPMSi), σ = 94 meV [22]; and for poly(2,7-(9,9-bis(2-ethylhexyl)fluorene)) (PF2/6), σ = 40meV [12]. In contrast, DCM2:Alq 3 films possess considerably less disorder as reflected in their narrow DOS.…”

Section: Temperatures Below the Transition (Ie T < T Trans ) Multimentioning

confidence: 99%

Temperature dependence of the exciton dynamics inDCM2:Alq3

2014

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We study the temperature dependence of the triplet and singlet exciton dynamics in the archetype small molecule fluorescent guest-host system, tris(8-hydroxyquinolinato) aluminum (Alq 3 ) doped with 4-(dicyanomethylene)-2-methyl-6-julolidyl-9-enyl-4H-pyran (DCM2). We develop a comprehensive model of the exciton dynamics, and use it to fit the transient photoluminescence under different pulsed optical pumping in the temperature range of 80 K< T< 295 K. The triplet decay has a significantly different temperature dependence than that of singlets. From 295K to 80K, the triplet-triplet annihilation (TTA) rate decreases by two orders of magnitude, whereas the singlet-triplet annihilation rate decreases by <50% primarily a result of the different energy transfer mechanisms of singlets and triplets. The temperature dependence of TTA rate reveals two regimes separated by a transition at 180K from Marcus to MillerAbrahams transfer. This work deepens our understanding of exciton dynamics and energy transfer in small molecule organic materials.2

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Section: Temperatures Below the Transition (Ie T < T Trans ) Multimentioning

confidence: 99%

Temperature dependence of the exciton dynamics inDCM2:Alq3

2014

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“…This indicates that the effective activation energy related to the disorder, E A,disorder , is large as compared to the activation energy associated with polaron hopping, E A,pol . Following Bässler 46 and Fishchuk, 47 the total effective Arrhenius activation energy for charge carrier hopping may be written as…”

Section: õ T Versus 1 õ T 2 Dependence Of the Mobilitymentioning

confidence: 99%

Hole transport in polyfluorene-based sandwich-type devices: Quantitative analysis of the role of energetic disorder

et al. 2008

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“…Charge transport in organic disordered systems is described in terms of thermally activated hopping between molecules. The materials conductivity is typically expressed as a function of temperature and hopping activation energy (E a ) [28][29][30] as…”

Section: Introductionmentioning

confidence: 99%

Investigation of the High Electron Affinity Molecular Dopant F6‐TCNNQ for Hole‐Transport Materials

Zhang

Kahn

2017

Adv Funct Materials

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2,2′-(perfluoronaphthalene-2,6-diylidene)dimalononitrile (F6-TCNNQ) is investigated as a molecular p-type dopant in two hole-transport materials, 2,2′,7,7′-tetrakis(N,N-diphenylamino)-9,9-spirobifluorene (Spiro-TAD) and tris(4-carbazoyl-9-ylphenyl)amine (TCTA). The electron affinity of F6-TCNNQ is determined to be 5.60 eV, one of the strongest organic molecular oxidizing agents used to date in organic electronics. p-Doping is found to be effective in Spiro-TAD (ionization energy = 5.46 eV) but not in TCTA (ionization energy = 5.85 eV). Optical absorption measurements demonstrate that charge transfer is the predominant doping mechanism in Spiro-TAD:F6-TCNNQ. The hostdopant interaction also leads to a significant alteration of the host film morphology. Finally, transport measurements done on Spiro-TAD:F6-TCNNQ as a function of dopant concentration and temperature, and using a highly doped contact layer to ensure negligible hole injection barrier, lead to an accurate measurement of the film conductivity and hole-hopping activation energy.

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Nondispersive polaron transport in disordered organic solids

Cited by 100 publications

References 32 publications

Temperature dependence of the exciton dynamics inDCM2:Alq3

Temperature dependence of the exciton dynamics inDCM2:Alq3

Hole transport in polyfluorene-based sandwich-type devices: Quantitative analysis of the role of energetic disorder

Investigation of the High Electron Affinity Molecular Dopant F6‐TCNNQ for Hole‐Transport Materials

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