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Los controles de embalaje en estado sólido de la deslocalización del excitón y la fotofísica en los receptores de no
Robert J E Westbrook1, Andrew J Levin2, Wei Gao3
1Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States.
Journal of the American Chemical Society
|August 5, 2025
Resumen
El empaque molecular diseñado en aceptores de no fullereno mejora la eficiencia fotovoltaica orgánica. Las bajas tasas de recombinación de excitones deslocalizados, impulsadas por el empaque frontal, aumentan la eficiencia cuántica interna.
Área de la Ciencia:
- Ciencias de los materiales
- Productos electrónicos orgánicos
- Las instalaciones fotovoltaicas
Sus antecedentes:
- Los aceptores de no fullereno (NFAs) son cruciales para los fotovoltaicos orgánicos (OPV).
- La comprensión de la dinámica del excitón en los NFA es clave para mejorar el rendimiento del dispositivo.
- El empaque molecular influye significativamente en el comportamiento del excitón y la generación de carga.
Objetivo del estudio:
- Investigar el impacto del empaque molecular en la deslocalización del excitón y la cinética de la recombinación en los derivados de Y6.
- Para correlacionar las propiedades del excitón con el rendimiento de los dispositivos fotovoltaicos orgánicos.
- Identificar los factores estructurales que mejoran la eficiencia cuántica interna (EQI) en las VPO.
Principales métodos:
- Espectroscopia de absorción transitoria para estudiar la formación y la dinámica de los excitones.
- Fotoexcitación selectiva en mezclas de donante y receptor para detectar mecanismos de generación de carga.
- Cuantificación de la cinética de la recombinación utilizando la constante de recombinación monomolecular (a).
- Diseminación de rayos X de gran angular de incidencia de pastoreo (GIWAXS) para analizar el empaque molecular.
Principales resultados:
- Pruebas de excitones locales y deslocalizados en películas netas de derivados de Y6.
- El donante D18 actúa como espectador durante la generación de carga después de la fotoexcitación del aceptor.
- Las constantes de recombinación más bajas (a) se correlacionan con un mayor rendimiento de transferencia de agujero y IQE.
- El empaquetado molecular de cara a cara promueve la deslocalización del excitón y un mayor IQE (hasta el 97,2% en T1).
Conclusiones:
- El empaquetado molecular, específicamente la orientación de cara, es un factor crítico para la deslocalización del excitón en los NFA.
- El control de la cinética de recombinación de excitones a través de la ingeniería molecular puede mejorar significativamente el rendimiento de OPV.
- Este estudio proporciona una palanca estructural para avanzar en la energía fotovoltaica orgánica hacia mayores eficiencias.
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