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Pruebas experimentales para la fotoisomerización de los fullerenos superiores
Clemens Burda1, Anna C S Samia, David J Hathcock
1Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA. burda@po.cwru.edu
Journal of the American Chemical Society
|October 17, 2002
Resumen
Los fullerenos más grandes muestran una dinámica de estado excitado más lenta, que se correlaciona con el número de isómeros y el mecanismo de isomerización de Stone-Wales. Esto sugiere el potencial para aplicaciones de puertas ópticas rápidas.
Área de la Ciencia:
- Química Física es la química física.
- Ciencia de los materiales Ciencia de los materiales.
- La fotofísica es la fotofísica.
Sus antecedentes:
- Los fullerenos (C60, C70, C76, C84, C86, C90) son alótropos de carbono con propiedades electrónicas únicas.
- Comprender la dinámica del estado excitado es crucial para su aplicación en optoelectrónica.
- El mecanismo de isomerización de Stone-Wales describe los cambios estructurales en las jaulas de carbono.
Objetivo del estudio:
- Para investigar la dinámica de relajación inicial de los fullerenos fotoexcitados.
- Para correlacionar la dinámica con el tamaño del fullereno y la isomerización.
- Para explorar las posibles aplicaciones en la puerta óptica.
Principales métodos:
- Espectroscopia de bomba-sonda de femtosegundo sin dispersión.
- Dinámica de monitoreo en las gamas espectrales del visible y del infrarrojo cercano (NIR).
- Análisis computacional de las vías de isomerización.
Principales resultados:
- La formación del estado excitado se ralentiza con el aumento del tamaño del fullereno.
- La dinámica se correlaciona con el número de isómeros y el mecanismo de Stone-Wales.
- La isomerización de Stone-Wales es fotoinducida y sin barreras.
- Las diferencias de energía de los isómeros son de aproximadamente 1 meV.
- La isomerización inversa ocurre en la escala de tiempo del picosegundo.
- Se observó una amplia absorción transitorio.
Conclusiones:
- El tamaño y el isomerismo del fullereno influyen significativamente en la relajación del estado excitado.
- La isomerización Stone-Wales fotoinducida es un factor clave.
- La amplia absorción transitorio indica el potencial para los dispositivos de puertas ópticas rápidas.
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