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Salmerón‐Valverde, A.; Robles‐Martínez, J. G.; Garcı́a-Serrano, J.; Gómez, R.; Ridaura, R.; Quintana, Manuel Sillero; Zehe, A.

doi:10.1023/a:1008384013189

Cited by 23 publications

(16 citation statements)

References 17 publications

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“…In spite of these limitations, the main conclusion agrees with previously reported Raman data for -(TTF-MeDC2TNF) ( = 0.32; Salmero Â n- Valverde et al, 1999). This value was obtained using the active Raman stretching mode of the central C C bond in TTF.…”

Section: X35 and 0x31xsupporting

confidence: 91%

Structure and degree of charge transfer of two polymorphs of a 1:1 molecular complex: [2,2′-bis-1,3-dithiole][9-dicyanomethylene-4,5,7-trinitrofluorene-2-carboxylic acid methyl ester] (TTF-MeDC2TNF)

Salmerón‐Valverde

Bernès

Robles‐Martínez

2003

Acta Crystallogr Sect B

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A new organic charge-transfer complex, C(18)H(7)N(5)O(8).C(6)H(4)S(4), has been prepared using TTF (tetrathiafulvalene) as a donor (D) and MeDC2TNF (9-dicyanomethylene-4,5,7-trinitro-fluorene-2-carboxylic acid methyl ester) as an acceptor (A). Two monoclinic polymorphs of the 1:1 salt were crystallized and characterized by X-ray diffraction. Form alpha crystallizes in space group P2(1)/n with Z' = 1, while form beta crystallizes in space group C2/c with Z' = 1/2 and the MeDC2TNF moiety disordered across a twofold axis. Both phases have mixed-stack crystal packings, which are characteristic of semiconducting one-dimensional organic complexes. However, the observed crystal packings are significantly different, with a single D...A interlayer separation of 3.452 A for the disordered beta polymorph and interlayer separations of 3.378 and 3.483 A in the case of the ordered alpha form. These variations are reflected in the degree of charge transfer, delta, which was estimated on the basis of the b(2u) stretching-mode frequency shift observed in the IR spectra for the cyano groups of the MeDC2TNF radical anion. The fact that the charge transfer is more efficient for alpha-(TTF-MeDC2TNF) than for beta-(TTF-MeDC2TNF) (delta = 0.35 and 0.31, respectively) is consistent with the structural features observed for each crystalline form.

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Section: X35 and 0x31xsupporting

confidence: 91%

Structure and degree of charge transfer of two polymorphs of a 1:1 molecular complex: [2,2′-bis-1,3-dithiole][9-dicyanomethylene-4,5,7-trinitrofluorene-2-carboxylic acid methyl ester] (TTF-MeDC2TNF)

Salmerón‐Valverde

Bernès

Robles‐Martínez

2003

Acta Crystallogr Sect B

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“…The conductivity is further limited by the rather small charge transfer, if one takes into account that high s-values should not be expected for r o 0.4. 35 In order to further analyze the influence of the geometry of the stacking on the conductivity behavior as well as the role of the specific acceptor F 4 TCNQ in more detail, we compare in this section the electronic properties of TMP-F 4 TCNQ and TMP-TCNQ. 31,34 TMP-TCNQ shows a mixed-stack arrangement like TMP-F 4 TCNQ but the low dimensionality is far less pronounced.…”

Section: Discussionmentioning

confidence: 99%

Charge transfer tuning by chemical substitution and uniaxial pressure in the organic complex tetramethoxypyrene–tetracyanoquinodimethane

Rudloff

Ackermann

Huth

et al. 2015

Phys. Chem. Chem. Phys.

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In the search for novel organic charge transfer salts with variable degrees of charge transfer we have studied the effects of two modifications of the recently synthesized donor-acceptor system [tetramethoxypyrene (TMP)]-[tetracyanoquinodimethane (TCNQ)]. One is of chemical nature by substituting the acceptor TCNQ molecules by F4TCNQ molecules. The second consists in simulating the application of uniaxial pressure along the stacking axis of the system. In order to test the chemical substitution, we have grown single crystals of the TMP-F4TCNQ complex and analyzed its electronic structure via electronic transport measurements, ab initio density functional theory (DFT) calculations and UV/VIS/IR absorption spectroscopy. This system shows an almost ideal geometrical overlap of nearly planar molecules stacked alternately (mixed stack) and this arrangement is echoed by a semiconductor-like transport behavior with an increased conductivity along the stacking direction. This is in contrast to TMP-TCNQ which shows a less pronounced anisotropy and a smaller conductivity response. Our band structure calculations confirm the one-dimensional behavior of TMP-F4TCNQ with pronounced dispersion only along the stacking axis. Infrared measurements illustrating the C≡N vibration frequency shift in F4TCNQ suggest however no improvement in the degree of charge transfer in TMP-F4TCNQ with respect to TMP-TCNQ. In both complexes about 0.1e is transferred from TMP to the acceptor. Concerning the pressure effect, our DFT calculations on the designed TMP-TCNQ and TMP-F4TCNQ structures under different pressure conditions show that application of uniaxial pressure along the stacking axis of TMP-TCNQ may be the route to follow in order to obtain a much more pronounced charge transfer.

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“…Additional peaks at 450 and 1200 nm appear originating from the reaction of the charge transfer between the host and dopant molecules. The charge transfer reaction can be further confirmed by Fourier transform infrared (FT‐IR) spectroscopy 63, 64. Charge transfer from the 2TNATA molecule to the metal complex dopant will modify the charge distribution of the 2TNATA molecule, and rearrange the binding energy between the atoms in the molecule of the charge transfer complex.…”

Section: Doped Organic/electrode Junctionsmentioning

confidence: 91%

Interfacial doping for efficient charge injection in organic semiconductors

Lee

Kim

2012

Physica Status Solidi (a)

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Interfacial doping in organic semiconductors (OSs) is an important technique to achieve efficient organic electronic devices. In this paper, we discuss how the charge injection into an OS can be enhanced by the insertion of a thin interfacial layer or an electrically doped OS layer between an electrode and an undoped OS. We present that the vacuum level shift and Fermi level modification by the electrical doping is the origin of the efficient charge injection through a metal-organic junction and an organic-organic junction. Application to organic electronics such as organic light-emitting diodes (OLEDs) and organic photovoltaics (OPVs) is briefly summarized.

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Cited by 23 publications

References 17 publications

Structure and degree of charge transfer of two polymorphs of a 1:1 molecular complex: [2,2′-bis-1,3-dithiole][9-dicyanomethylene-4,5,7-trinitrofluorene-2-carboxylic acid methyl ester] (TTF-MeDC2TNF)

Structure and degree of charge transfer of two polymorphs of a 1:1 molecular complex: [2,2′-bis-1,3-dithiole][9-dicyanomethylene-4,5,7-trinitrofluorene-2-carboxylic acid methyl ester] (TTF-MeDC2TNF)

Charge transfer tuning by chemical substitution and uniaxial pressure in the organic complex tetramethoxypyrene–tetracyanoquinodimethane

Interfacial doping for efficient charge injection in organic semiconductors

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