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Una mirada cercana a la generación de carga en el polímero: el fullereno se mezcla con el control de la
Mariateresa Scarongella1, Jelissa De Jonghe-Risse, Ester Buchaca-Domingo
1Institute of Chemical Sciences & Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) , SB ISIC GR-MO, Station 6, CH-1015 Lausanne, Switzerland.
Journal of the American Chemical Society
|February 5, 2015
Resumen
La generación de carga en las mezclas de polímeros: fullereno está limitada por la difusión de excitones, pero se acelera en las regiones mezcladas. La migración ultrarrápida de agujeros de dominios entremezclados a dominios ordenados evita la recombinación en los sistemas pBTTT:PCBM.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- La energía fotovoltaica es fotovoltaica.
- Electrónica orgánica y electrónica orgánica.
Sus antecedentes:
- Las mezclas de polímeros y fullereno son cruciales para las células solares orgánicas.
- Comprender los mecanismos de generación de carga es clave para mejorar la eficiencia del dispositivo.
- El control de la microestructura a través de aditivos influye en el rendimiento de la mezcla.
Objetivo del estudio:
- Para aclarar los mecanismos de generación de carga en pBTTT: mezclas de PCBM.
- Para investigar el papel de la microestructura y la morfología de dominio.
- Comprender la dinámica de la difusión del excitón y la separación de cargas.
Principales métodos:
- Espectroscopia de absorción transitorio ultrarrápida con espectroscopia de absorción transitoria.
- La espectroscopia de electroabsorción (efecto Stark) es una técnica de espectroscopia.
- Espectroscopia de fluorescencia de conversión hacia arriba.
- Procesamiento con aditivos de éster metílico de ácido graso.
Principales resultados:
- La difusión del excitón en los dominios de puridad de fase limita las tasas de transferencia de carga.
- La separación de carga rápida ocurre en regiones molecularmente mezcladas (fase cocristalina).
- Los dominios de Neat son vitales para prevenir la recombinación de geminados.
- Visualización directa de la migración del agujero subpicosegundo desde dominios mezclados a dominios ordenados.
Conclusiones:
- La mezcla molecular y los dominios ordenados son fundamentales para una eficiente generación y separación de cargas.
- El transporte ultrarrápido de agujeros es facilitado por cascadas de energía y alta movilidad local.
- El control de la microestructura es esencial para optimizar el rendimiento fotovoltaico orgánico.
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