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Transferencia de carga desde la conversión de nanocristales a electrodos semiconductores: optimización de las salidas

Bing Shan¹, Ting-Ting Li^1,2, M Kyle Brennaman¹

¹Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States.

Journal of the American Chemical Society

|December 12, 2018

Resumen

Los investigadores desarrollaron nuevos ensamblajes de nanocristales de conversión ascendente para una conversión eficiente de energía solar. Estos conjuntos, que utilizan nanocristales de selenuro de cadmio (CdSe) y antracenos, permiten una inyección efectiva de carga para dispositivos fotoelectroquímicos avanzados.

Área de la Ciencia:

Ciencias de los materiales
Nanotecnología
La fotoquímica

Sus antecedentes:

Los nanocristales inorgánicos son cruciales para la conversión de energía solar y los dispositivos optoelectrónicos.
El desarrollo de fotosensibilizadores eficientes es clave para el avance de las células fotoelectroquímicas.

Objetivo del estudio:

Para crear una nueva familia de fotoelectrodos utilizando ensamblajes de nanocristales de conversión hacia arriba.
Investigar el mecanismo de inyección de carga eficiente permitido por estos conjuntos.

Principales métodos:

Nanocristales sintetizados de selenuro de cadmio (CdSe) cubiertos con ácido oleico.
Desarrolló una estrategia para coordinar los nanocristales de CdSe en los antracenos sujetos a la superficie, desplazando a los ligandos del ácido oleico.
Se utilizó la espectroscopia de emisión en estado estacionario y de absorción transitoria para analizar la formación de excitones y la inyección de carga.
Se realizó un análisis de la densidad del estado para comprender el acoplamiento electrónico y la transferencia de carga.

Principales resultados:

Se han creado con éxito ensamblajes de nanocristales de conversión ascendente para aplicaciones de fotoelectrodos.
Se ha demostrado la generación eficiente de excitones singlet por excitación con luz verde a través de la aniquilación triplet-triple sensibilizada en antracenos.
Se logra una inyección eficiente de carga tanto en TiO2 (fotoanodo) como en NiO (fotocátodo) a través de los excitones singlet generados.
Estableció una base termodinámica para la transferencia de carga inducida por la luz a través del acoplamiento electrónico entre los estados excitados de antraceno y los óxidos metálicos.

Conclusiones:

Los ensamblajes de nanocristales de conversión ascendente desarrollados ofrecen una estrategia prometedora para los dispositivos fotoelectroquímicos de próxima generación.
Los hallazgos proporcionan nuevos principios de diseño para superar las limitaciones de las células fotoelectroquímicas sensibles al tinte actuales, particularmente para aplicaciones catalíticas.
La interacción entre las moléculas sujetas a la superficie y los nanocristales es crucial para la recolección eficiente de luz y la transferencia de carga.

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