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Auto-dopaje asistido por enlace de hidrógeno en el conductor de tetratiofulvaleno (TTF)
Yuka Kobayashi1, Mayu Yoshioka, Kazuhiko Saigo
1Waseda Institute for Advanced Study, Waseda University, Tokyo, 169-8050, Japan. yuka@aoni.waseda.jp
Journal of the American Chemical Society
|July 3, 2009
Resumen
El tetratiafulvaleno-2-carboxilato de amonio (TTFCOO(-)NH(4)(+)) se transforma de un aislante a un conductor autodoado a través de la protonación. El enlace de hidrógeno facilita esta transformación, creando un nuevo "conductor auto-dopado asistido por enlace de hidrógeno" con propiedades semiconductoras.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química del estado sólido.
- Electrónica orgánica y electrónica orgánica.
Sus antecedentes:
- Los derivados del tetratiafulvaleno (TTF) son ampliamente estudiados por sus propiedades conductoras.
- Lograr un auto-dopaje controlado en conductores orgánicos sigue siendo un desafío significativo.
- Comprender el papel de las interacciones intermoleculares en la sintonización de las propiedades electrónicas es crucial.
Objetivo del estudio:
- Para sintetizar y caracterizar el tetratio fulvaleno-2-carboxilato de amonio (TTFCOO(-)NH(4)(+)).
- Para dilucidar el mecanismo de generación de la portadora y las características orbitales moleculares de este conductor auto-dopado.
- Para investigar la influencia de la unión de hidrógeno en el comportamiento conductor.
Principales métodos:
- Síntesis de TTFCOO(-)NH(4)(+) a partir del TTFCOOH.
- Caracterización mediante espectroscopia UV-vis, ESR y 1H RMN.
- Cristalografía de rayos X para determinar la estructura cristalina.
- Cálculos orbitales moleculares (modelos de clúster y cálculos periódicos desde el principio).
- Medición de la conductividad eléctrica y el efecto isotópico.
Principales resultados:
- El TTFCOOH aislante se convierte en un conductor dopado con agujero (TTFCOO(-)NH(4)(+)) con una conductividad sigma = 2.0 x 10(-4) S/cm a 300 K.
- La protonación de la porción TTF genera una especie radical (TTF (((*+) COO (((-) NH (((4) ((+)).
- La estructura de rayos X revela matrices supramoleculares TTFCOO(-) unidas por enlaces de hidrógeno.
- Los cálculos orbitales moleculares indican un estado de caparazón casi cerrado para el radical.
- El enlace de hidrógeno contribuye significativamente a la conducción de electrones, evidenciado por un gran efecto isotópico.
Conclusiones:
- TTFCOO(-)NH(4)(+) es un nuevo "conductor auto-dopado asistido por enlace de hidrógeno".
- El auto-dopaje se logra a través de la protonación de la unidad TTF.
- La red de enlaces de hidrógeno juega un papel crítico en el ensamblaje de las fracciones TTF y facilita el comportamiento semiconductor.
- Este estudio ofrece una nueva estrategia para el diseño de conductores orgánicos con propiedades sintonizables.
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