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Polarizabilidad de excitación con resolución espectral para comprender la generación de carga en diodos de
Enoch Go1,2, Hyunjung Jin1,2, Seongwon Yoon1
1Advanced Photovoltaics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea.
Journal of the American Chemical Society
|May 17, 2024
Resumen
La comprensión de la generación de carga en los dispositivos de heterounión en masa orgánica (BHJ) es clave. Descubrimos que una mayor polarizabilidad del excitón en las películas BHJ conduce a una eficiencia de generación de carga casi perfecta.
Área de la Ciencia:
- Ciencias de los materiales
- Productos electrónicos orgánicos
- Las instalaciones fotovoltaicas
Sus antecedentes:
- El mecanismo de generación de carga en los dispositivos orgánicos de heterounión a granel (BHJ) sigue siendo incompleto.
- Los métodos convencionales luchan por aislar las propiedades dieléctricas de los donantes y aceptadores de electrones en las mezclas, lo que dificulta el análisis de las eficiencias de generación de carga.
Objetivo del estudio:
- Investigar el papel de la polarizabilidad del estado excitado en los dispositivos BHJ orgánicos.
- Para correlacionar las propiedades moleculares con la eficiencia de generación de carga en los sistemas BHJ.
Principales métodos:
- Se utilizó la espectroscopia de electroabsorción con resolución espectral.
- Se analizó la polarizabilidad de donantes y aceptadores individuales en películas de mezcla orgánica.
Principales resultados:
- Se estableció un vínculo directo entre una mayor polarizabilidad del excitón, una mayor longitud de coherencia π-π y una transferencia de carga acelerada.
- Se demostró que el empaque molecular en las películas de BHJ mejora sinérgicamente la polarizabilidad del excitón.
Conclusiones:
- La polarizabilidad del excitón es un factor fundamental que impulsa la alta eficiencia de generación de carga en los dispositivos BHJ.
- Los hallazgos proporcionan una explicación mecanicista para una eficiencia de generación de carga cercana al 100% en los fotodiodos BHJ.
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