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Fotoconductor molecular con espines localizados simultáneamente fotocontrolables
Toshio Naito1, Tomoaki Karasudani, Shigeki Mori
1Graduate School of Science and Engineering, Ehime University, Matsuyama, Japan. tnaito@ehime-u.ac.jp
Journal of the American Chemical Society
|September 6, 2012
Resumen
La luz UV transforma un cristal aislante en un conductor magnético al desencadenar una reacción fotoquímica reversible. Este proceso crea fotocorrientes y espines localizados, lo que demuestra el control óptico sobre las propiedades del material.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Física del estado sólido Física del estado sólido
- La fotoquímica es la fotoquímica.
Sus antecedentes:
- Los cristales moleculares ofrecen propiedades electrónicas sintonizables.
- El control de la conductividad y el magnetismo en los materiales es un área de investigación clave.
- Las reacciones fotoquímicas pueden inducir cambios significativos en los estados de los materiales.
Objetivo del estudio:
- Para investigar la conmutación reversible fotoinducida de las propiedades electrónicas y magnéticas de un cristal molecular.
- Para explorar el mecanismo detrás de la transformación de un aislante no magnético a un conductor magnético.
- Comprender el papel de las transiciones de transferencia de carga en la fotoconductividad y el fotomagnetismo.
Principales métodos:
- Síntesis y caracterización del cristal molecular BPY[Ni(dmit)(2)](2).
- Experimentos de irradiación UV para inducir y observar cambios en las propiedades.
- Mediciones de fotocorriente para cuantificar los cambios de conductividad.
- Espectroscopia de resonancia de espín de electrones (ESR) para detectar espines localizados.
Principales resultados:
- La irradiación UV convierte reversiblemente el cristal aislante y no magnético BPY (Ni) en un conductor magnético.
- Se observó un aumento significativo en la conductividad (1 orden de magnitud) y la generación de espines localizados bajo luz UV.
- Los fenómenos observados se atribuyen a una reacción redox fotoquímica y las transiciones de transferencia de carga.
- El material exhibe un control óptico reversible, cambiando entre una sal iónica y un estado complejo de transferencia de carga.
Conclusiones:
- BPY[Ni(dmit)((2)](2) es un nuevo material que exhibe fotocambio reversible entre los estados de aislamiento y conductividad magnética.
- La fotoconductividad y el fotomagnetismo son impulsados por la transferencia de carga inducida por los rayos UV y las reacciones redox.
- Este trabajo demuestra una vía para controlar ópticamente las propiedades electrónicas y magnéticas de los materiales moleculares.
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