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Efecto del paisaje energético interfacial en la generación de carga inducida por la luz en la interfaz ZnPc/MoS2
Tika R Kafle1, Bhupal Kattel1, Peng Yao1,2
1Department of Physics and Astronomy , University of Kansas , Lawrence , Kansas 66045 , United States.
Journal of the American Chemical Society
|July 2, 2019
Resumen
Los excitones de transferencia de carga en las interfaces orgánicas / MoS2 se comportan de manera diferente. El paisaje de energía potencial, no solo la alineación de bandas, dicta la separación de cargas en portadores libres.
Área de la Ciencia:
- Ciencias de los materiales
- Química Física
- Ciencias de la superficie
Sus antecedentes:
- Los cristales monocapa de dicalcogenuro de metales de transición (TMDC) forman heteroestructuras con moléculas orgánicas.
- La transferencia de carga ultrarrápida (CT) ocurre en las interfaces orgánicas / TMDC, pero la separación de excitones en portadores libres no se entiende completamente.
Objetivo del estudio:
- Investigar la transferencia de carga y la dinámica de los excitones en las interfaces entre ftaalocianina de zinc (ZnPc) y MoS2.
- Comprender las condiciones que favorecen la separación de cargas frente a la recombinación.
Principales métodos:
- Espectroscopia de fotoemisión con resolución de tiempo y estado estacionario.
- Se estudiaron las interfaces ZnPc/monocapa MoS2 y ZnPc/monocapa MoS2.
Principales resultados:
- Ambas interfaces muestran alineación de banda tipo II y transferencia de carga ultrarrápida (<100 fs).
- El ZnPc/monocapa MoS2 facilita la disociación del excitón en portadores libres.
- ZnPc / MoS2 a granel exhibe transferencia de electrones hacia atrás, formando excitones triplet en ZnPc debido a las diferencias de flexión de la banda.
Conclusiones:
- El paisaje de energía potencial influye significativamente en la separación de carga interfacial.
- La alineación del nivel de energía por sí sola es insuficiente para predecir la generación de carga libre en las interfaces orgánicas/TMDC.
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