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Mecanismo de transferencia de electrones de ioduro único de la esfera interna para la regeneración del tinte en las
Jiwon Jeon1, William A Goddard, Hyungjun Kim
1Graduate School of Energy Environment Water Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea.
Journal of the American Chemical Society
|February 7, 2013
Resumen
Se vuelve a examinar el proceso de yoduro único (SIP) en las células solares sensibilizadas al tinte. Un nuevo mecanismo de transferencia de electrones de la esfera interna (ISET) explica la regeneración eficiente del tinte, mejorando el rendimiento de las células solares.
Área de la Ciencia:
- La energía fotovoltaica es fotovoltaica.
- Ciencia de los materiales Ciencia de los materiales.
- La electroquímica es electroquímica.
Sus antecedentes:
- Las células solares sensibles al tinte (DSSC) dependen de las parejas redox para la regeneración del tinte.
- La pareja redox yoduro/trioduro (I-/I3-) es crucial para la regeneración de tintes oxidados.
- Los modelos existentes para la regeneración de tintes, como el proceso de un solo yodo (SIP) y el proceso de dos yodo (TIP), se enfrentan a inconsistencias teóricas y experimentales.
Objetivo del estudio:
- Para investigar el mecanismo de transferencia de electrones entre yoduro y tintes oxidados en DSSCs.
- Para resolver las discrepancias entre las predicciones teóricas y las observaciones experimentales de la cinética de regeneración de colorantes.
- Proponer un nuevo modelo que describa con precisión el proceso de regeneración del tinte.
Principales métodos:
- Se emplearon cálculos de mecánica cuántica para estudiar el proceso de transferencia de electrones.
- Se incorporó el modelo de disolución de Poisson-Boltzmann para tener en cuenta los efectos del disolvente.
- Se examinó el caso específico del tinte N3 (Ru ((dcb) 2 ((NCS) 2) y el yoduro.
Principales resultados:
- Los iones yoduro son atraídos por el tinte oxidado, específicamente cerca del ligando NCS.
- Una transferencia parcial de electrones (aprox. 40%) del yoduro al tinte se produce en la posición de equilibrio.
- Esta interacción es facilitada por la desolución parcial del yoduro, lo que permite la transferencia de electrones en la esfera interna (ISET).
Conclusiones:
- El modelo propuesto de transferencia de electrones de la esfera interna-proceso de yoduro único (ISET-SIP) reconcilia los potenciales redox y los datos experimentales.
- El mecanismo ISET-SIP proporciona una descripción más precisa de la cinética de regeneración del tinte en las DSSC.
- Esta comprensión permite el rediseño de ligandos dirigidos para mejorar la eficiencia de la regeneración del tinte.
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