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Identificación de los mecanismos de transferencia de carga a través de las estructuras heterogéneas de
Ryan T Pekarek1, Kara Kearney2,3, Benjamin M Simon1
1Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712 , United States.
Journal of the American Chemical Society
|October 4, 2018
Resumen
La transferencia de agujeros a través de fotoánodos de silicio protegidos por TiO2 está controlada por dipolos moleculares interfaciales, que ocurren a través de la emisión termoiónica o el túnel intrabanda. Este estudio mejora la comprensión del transporte de cargas en dispositivos fotoelectroquímicos.
Área de la Ciencia:
- Ciencias de los materiales
- La electroquímica
- Ciencias de la superficie
Sus antecedentes:
- Los dispositivos fotoelectroquímicos eficientes se basan en heterojunciones complejas.
- Comprender el transporte de carga a través de estas interfaces es crucial pero desafiante.
- El dióxido de titanio (TiO2) es una capa protectora común para semiconductores.
Objetivo del estudio:
- Para analizar la transferencia de agujeros a través de los fotoánodos n-Si(111)-R
- Para investigar el papel de los dipolos moleculares interfaciales en el transporte de carga.
- Desarrollar y validar un modelo computacional multiscala para predecir el transporte de cargas.
Principales métodos:
- Caracterización experimental: espectroscopia de fotoelectrones de rayos X, voltametría y espectroscopia de impedancia.
- Modelado computacional: Teoría funcional de densidad de los primeros principios (DFT) y modelado de dispositivos de elementos finitos.
- Validación con parejas redox no acuosas (derivados del ferroceno).
Principales resultados:
- El transporte por agujero está limitado en la interfaz n-Si(111)-R
- El transporte de carga se produce a través de la emisión termoiónica y / o el túnel intrabanda, regulado por dipolos moleculares interfaciales.
- Un enfoque combinado de DFT / modelado de dispositivos predijo con precisión el comportamiento de transporte de carga.
Conclusiones:
- Se proporciona una comprensión básica del transporte de carga a través de electrodos protegidos con TiO2.
- Se demuestra la capacidad predictiva del enfoque combinado DFT/modelado de dispositivos.
- Este trabajo ofrece ideas para diseñar dispositivos fotoelectroquímicos estables y eficientes.
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