Protonic defect induced carrier doping in TTFCOO−NH4+: Tunable doping level by solvent

Terauchi, Takeshi; Kobayashi, Yuka; Iwaï, Hideo; Tanaka, Akihiro

doi:10.1016/j.synthmet.2012.01.026

Cited by 9 publications

(6 citation statements)

References 29 publications

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“…The activation energy is also quite similar: 0.16 eV for TTFCOONH 4 and 0.19 eV for TTFCOOND 4 . This agreement is reasonable given that the doping levels and electronic properties of spin are similar, as shown in previous ESR studies, 18,20 and the optical absorption is in the nearinfrared region (ESI †). Moreover, X-ray diffraction patterns are isomorphous at 300 K (ESI †).…”

Section: Thermopower Of Ttfcoonh 4 and Ttfcoondsupporting

confidence: 91%

“…The origin of doping is claried as the naturally arising protonic defects in the 2DSB, as two kinds of nitrogen core-level peaks were detected in H by means of X-ray photoelectron spectroscopy. 20 The protonic defects in the salt bridge allow for the inclusion of TTF_ + COO À in an array of closed-shell TTF moieties and provide an acceptor level, giving rise to semiconducting properties (see ESI †). We evaluated the ratio of the peaks in TTFCOONH 4 and TTFCOOND 4 by hard X-ray photoelectron spectroscopy (HAXPES) using synchrotron radiation for the quantitative determination of the protonic defect.…”

Section: Characterization Of the Chemical State With Defectsmentioning

confidence: 99%

“…The origin of hole doping inherently includes protonic defects in salt-bridge networks. 20 Defective structures derived from the nonstoichiometry of compounds oen allow ion transport, as known in fuel cell solid oxides, 21 and the situation of TTFCOONH 4 strongly suggests the possibility of proton transport via the defects. Herein, we report the proton transport and its effect on the thermopower of TTFCOONH…”

Section: Introductionmentioning

confidence: 99%

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Room-temperature proton transport and its effect on thermopower in a solid ionic semiconductor, TTFCOONH4

et al. 2013

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Ammonium proton in a solid ionic semiconductor, TTFCOONH 4 , is shown to be mobile under anhydrous conditions at room temperature by the hydrogen concentration cell method. Isotope substituted TTFCOOND 4 exhibits a 2.2 H/D isotope effect in ion carrier mobility with TTFCOONH 4 . First-principles calculations reveal that an efficient proton-transfer pathway via low-barrier N/H + /N hydrogen bonds reduces the activation energy to 0.12 eV, which is quite small and comparable to that reported in a bulk water system. The ac conductivity of TTFCOONH 4 and TTFCOOND 4 is similar at room temperature, reflecting similar hole carrier concentrations. In sharp contrast, the thermopower exhibits a large isotope effect: TTFCOONH 4 shows 260 mV K À1 , which is twice as large as that predicted by the hole carrier concentration and the value of TTFCOOND 4 , with 138 mV K À1 . The 1.9 H/D isotope effect in thermopower closely relates to the 2.2 H/D isotope effect in ion carrier mobility. Proton carriers in the temperature gradient enhance thermopower without cancelling out the effect of holes in the solid state owing to possession of the same positive charge.

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Section: Thermopower Of Ttfcoonh 4 and Ttfcoondsupporting

confidence: 91%

Section: Characterization Of the Chemical State With Defectsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Room-temperature proton transport and its effect on thermopower in a solid ionic semiconductor, TTFCOONH4

et al. 2013

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“…Specifically, radical autogeneration in TTF via protonation‐assisted disproportionation is well established; in crystals of ammonium tetrathiafulvalene‐2‐carboxylate, TTFCOO − NH 4 + , intermolecular hydrogen bonding promotes similar self‐doping, establishing a new type of carrier generation mechanism in organic semiconductors. Importantly, the SOMO of the TTF + •COO − NH 4 + unit is not the highest occupied orbital, according to the single‐ and multireference calculations on the model tetramer …”

Section: Quasi Closed‐shell Moleculesmentioning

confidence: 99%

Theory and practice of uncommon molecular electronic configurations

Gryn’ova

Coote

Corminbœuf

2015

WIREs Comput Mol Sci

100

112

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The electronic configuration of the molecule is the foundation of its structure and reactivity. The spin state is one of the key characteristics arising from the ordering of electrons within the molecule's set of orbitals. Organic molecules that have open-shell ground states and interesting physicochemical properties, particularly those influencing their spin alignment, are of immense interest within the up-and-coming field of molecular electronics. In this advanced review, we scrutinize various qualitative rules of orbital occupation and spin alignment, viz., the aufbau principle, Hund's multiplicity rule, and dynamic spin polarization concept, through the prism of quantum mechanics. While such rules hold in selected simple cases, in general the spin state of a system depends on a combination of electronic factors that include Coulomb and Pauli repulsion, nuclear attraction, kinetic energy, orbital relaxation, and static correlation. A number of fascinating chemical systems with spin states that fluctuate between triplet and open-shell singlet, and are responsive to irradiation, pH, and other external stimuli, are highlighted. In addition, we outline a range of organic molecules with intriguing non-aufbau orbital configurations. In such quasi-closed-shell systems, the singly occupied molecular orbital (SOMO) is energetically lower than one or more doubly occupied orbitals. As a result, the SOMO is not affected by electron attachment to or removal from the molecule, and the products of such redox processes are polyradicals. These peculiar species possess attractive conductive and magnetic properties, and a number of them that have already been developed into molecular electronics applications are highlighted in this review. How to cite this article:WIREs Comput Mol Sci 2015Sci , 5:440-459. doi: 10.1002Sci /wcms.1233 INTRODUCTIONT he electronic configuration and state of a molecule characterize the distribution of electrons across the corresponding one-electron wavefunctions, i.e., orbitals. 1 This model description, albeit approximate, is nonetheless indispensable in explaining and predicting molecular geometry and various chemical and physical properties. As orbitals comprise not only the spatial component, but also the spin, they also give rise to such key features as the nature of configuration shell-open or closed-and the multiplicity of the electronic state. While the majority of stable organic molecules have a closed-shell singlet ground state, species with unpaired electrons display unique chemical reactivity and are capable of carrying magnetism and conductivity functionalities. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.Although historically the latter have been the domain of metals and, in particular, transition metal complexes, in the recent years the focus has ...

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“…The salt‐bridge network acts as dopant in this carrier‐doping system,3b and the number of protonic defects is very important to know the doping level of the crystals. X‐ray photoelectron spectroscopy (XPS) is a powerful tool for investigating the number of defects, but supramolecules composed purely of light elements and multiple molecular components are not easily measured for several reasons, namely surface oxidation in air and anisotropy of the molecular array.…”

Section: Resultsmentioning

confidence: 99%

Isotope Effect of Thermopower in the TTFCOONH₃Ph Single Crystal

et al. 2014

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Protonic defect induced carrier doping in TTFCOO−NH4+: Tunable doping level by solvent

Cited by 9 publications

References 29 publications

Room-temperature proton transport and its effect on thermopower in a solid ionic semiconductor, TTFCOONH4

Room-temperature proton transport and its effect on thermopower in a solid ionic semiconductor, TTFCOONH4

Theory and practice of uncommon molecular electronic configurations

Isotope Effect of Thermopower in the TTFCOONH₃Ph Single Crystal

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Protonic defect induced carrier doping in TTFCOO−NH4+: Tunable doping level by solvent

Cited by 9 publications

References 29 publications

Room-temperature proton transport and its effect on thermopower in a solid ionic semiconductor, TTFCOONH4

Room-temperature proton transport and its effect on thermopower in a solid ionic semiconductor, TTFCOONH4

Theory and practice of uncommon molecular electronic configurations

Isotope Effect of Thermopower in the TTFCOONH3Ph Single Crystal

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Isotope Effect of Thermopower in the TTFCOONH₃Ph Single Crystal