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Autoensamblado simple hexagonal AB(2) superrejas de nanocristales binarios: SEM, GISAXS y defectos
Danielle K Smith1, Brian Goodfellow, Detlef-M Smilgies
1Department of Chemical Engineering, Texas Materials Institute, Center for Nano- and Molecular Science and Technology, The University of Texas at Austin, Austin, Texas 78712-1062, USA.
Journal of the American Chemical Society
|February 17, 2009
Resumen
Se ensamblaron con éxito superredes binarias (BSL) compuestas de óxido de hierro y nanocristales de oro. Estas estructuras exhiben una disposición hexagonal simple AB(2), con la contracción de la celosía observada y los cambios de simetría durante la deposición.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Nanotecnología La nanotecnología es la nanotecnología.
- La cristalografía es una técnica de cristalografía.
Sus antecedentes:
- Las superredes binarias (BSL) ofrecen propiedades sintonizables a través de la disposición controlada de nanopartículas de diferentes tamaños.
- El autoensamblaje de nanocristales es una estrategia clave para crear nanomateriales ordenados.
- Comprender los matices estructurales de las BSL es crucial para su aplicación.
Objetivo del estudio:
- Para ensamblar y caracterizar superredes binarias (BSL) de óxido de hierro y nanocristales de oro.
- Para dilucidar el ordenamiento estructural y la simetría de las BSL ensambladas.
- Para investigar los efectos de la interacción del sustrato y el secado en la estructura de BSL.
Principales métodos:
- Evaporación lenta de las dispersiones coloidales en sustratos inclinados.
- Microscopía electrónica de transmisión (TEM) y microscopía electrónica de barrido (SEM) para el análisis estructural.
- Diseminación de rayos X de ángulo pequeño de incidencia de pastoreo (GISAXS) para orden de largo alcance y parámetros estructurales.
Principales resultados:
- Ensamblaje de superredes binarias simples hexagonales (sh) AB(2) (isostruturales con AlB(2)).
- Confirmación del orden de largo alcance e identificación de la disposición de los nanocristales (Fe2O3 grande en la red, Au pequeño en los sitios intersticiales).
- Observación de la contracción de la superrejilla (8-12%) perpendicular al sustrato debido al secado con disolvente, lo que lleva a una simetría ortorrómbica centrada en (100) planos.
- Identificación de las dislocaciones de superredes compuestas de semiplanos de nanocristales de oro insertados.
Conclusiones:
- Las BSL de Fe ((2) O ((3) y nanocristales Au se pueden ensamblar en estructuras ordenadas sh-AB ((2).
- El secado con disolventes induce una contracción estructural significativa y cambios de simetría.
- El estudio proporciona información sobre los mecanismos de autoensamblaje y la estabilidad estructural de las superretillas de nanocristal.
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