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Transferencia de carga inducida por la foto desde puntos cuánticos medidos por voltametría cíclica

Micaela K Homer¹, Ding-Yuan Kuo¹, Florence Y Dou¹

¹Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States.

Journal of the American Chemical Society

|July 27, 2022

Resumen

Los investigadores desarrollaron un nuevo método que utiliza la voltametría cíclica para medir las tasas de transferencia de carga en los fotocatalizadores de puntos cuánticos. Esta técnica revela estados de carga de larga duración y proporciona velocidades relevantes para las transformaciones químicas.

Área de la Ciencia:

Ciencias de los materiales
La electroquímica
Fotocatálisis

Sus antecedentes:

Los puntos cuánticos (QD) son fotocatalizadores prometedores, pero la comprensión de la transferencia de carga en sus interfaces es clave.
La separación y transferencia de cargas eficientes son críticas para la actividad fotocatalítica.

Objetivo del estudio:

Desarrollar un método para medir las tasas de transferencia de carga fotoinducidas en las interfaces de puntos cuánticos.
Investigar la influencia de la fuerza motriz en las tasas de transferencia de carga.
Para correlacionar la dinámica de transferencia de carga con el rendimiento fotocatalítico.

Principales métodos:

Utilizó la voltametría cíclica bajo iluminación para sondear la transferencia de carga fotoinducida.
Empleado una biblioteca de aceptores de carga molecular (agujeros y aceptores de electrones).
Modelado electroquímico aplicado y diagrama de la zona ErCi' para el análisis mecanicista.

Principales resultados:

Demostró la medición de las tasas de transferencia de carga de los puntos cuánticos de CdS.
Se han observado estados de donantes de carga de larga duración debido al fotodoping nativo.
Encontré una correlación positiva entre la fuerza motriz y la velocidad de transferencia de carga.
Las tasas de transferencia de carga medidas son del orden de 0,1 s-1.

Conclusiones:

La voltametría cíclica bajo iluminación es efectiva para cuantificar la transferencia de carga en fotocatalizadores QD.
Las velocidades medidas son más relevantes para los rendimientos cuánticos fotocatalíticos que para la espectroscopia transitorio de picosegundos.
Este método proporciona información sobre la optimización de las interfaces QD para una fotocatálisis mejorada.

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