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Transferencia de carga intermolecular mediada por excimer en tintes autoensamblados de donante y receptor en óxidos
Yongze Yu1, Szu-Chia Chien2, Jiaonan Sun1
1Department of Chemistry and Biochemistry , The Ohio State University , Columbus , Ohio 43210 , United States.
Journal of the American Chemical Society
|May 17, 2019
Resumen
Los investigadores observaron la formación de excímeres intermoleculares en las moléculas de colorante autoensambladas en los óxidos metálicos. Este hallazgo revela un nuevo mecanismo para la separación de cargas, que podría mejorar los dispositivos fotoelectroquímicos.
Área de la Ciencia:
- Ciencias de los materiales
- La fotoquímica
- Química de las superficies
Sus antecedentes:
- El autoensamblaje de moléculas conjugadas en superficies de semiconductores es crucial para la dinámica de transferencia de electrones interfacial en la optoelectrónica.
- Comprender el acoplamiento electrónico en estos conjuntos es clave para optimizar el rendimiento del dispositivo.
Objetivo del estudio:
- Investigar el autoensamblaje de las moléculas de trifenilamina-oligotiofeno-perilenemonoimida (PMI) en las superficies de óxidos metálicos.
- Explorar las propiedades de interfaz resultantes y la dinámica de transferencia de electrones.
- Informar sobre la primera observación experimental de la formación de excimeros intermoleculares en monocapas autoensambladas de donante y receptor.
Principales métodos:
- Espectroscopia por absorción de rayos UV
- Espectroscopia por fotoluminiscencia
- Espectroscopia de absorción en el infrarrojo cercano
- Simulaciones de dinámica molecular
Principales resultados:
- Observación experimental de la formación de excimeros intermoleculares debido a las interacciones π-π entre las unidades PMI.
- Identificación de una separación de carga intermolecular de larga duración (4,3 μs).
- Propuesta de un nuevo mecanismo de transferencia de carga intermolecular mediado por excímero.
Conclusiones:
- El estudio demuestra la primera evidencia experimental de formación de excímero intermolecular en monocapas autoensambladas de donante y receptor.
- Se propone un nuevo mecanismo de transferencia de carga mediado por excímero, que ofrece información sobre la transferencia interfacial de electrones.
- Las moléculas de colorantes diseñados que forman agregados excitados pueden desacelerar las tasas de recombinación en los fotoelectrodos, mejorando la eficiencia del dispositivo.
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