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Un mecanismo de fluctuación de enlaces para la conmutación estocástica en moléculas cableadas
Ganesh K Ramachandran1, Theresa J Hopson, Adam M Rawlett
1Department of Physics and Astronomy, Arizona State University, Tempe, AZ 85287, USA.
Science (New York, N.Y.)
|May 31, 2003
Resumen
Se observó una conmutación estocástica de conductividad de encendido-apagado en alcanetiolos simples en superficies de oro. La movilidad molecular en la interfaz de oro, no los cambios electrónicos internos, probablemente causa este comportamiento de conmutación.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química de las superficies.
- La electrónica molecular es la electrónica molecular.
Sus antecedentes:
- La conmutación estocástica de conductividad en-apagado es un fenómeno observado en dispositivos electrónicos moleculares.
- Las explicaciones anteriores para este cambio en los oligómeros de fenileno-etinile implicaron cambios conformacionales o localización de electrones.
- Las moléculas cableadas más simples, los alcanetiolos, ofrecen un sistema fundamental para investigar este comportamiento.
Objetivo del estudio:
- Para investigar la conmutación estocástica de conductividad encendido-apagado en los alcanetiolos.
- Para determinar el mecanismo subyacente responsable de la conmutación en estos sistemas moleculares simples.
- Explorar el papel de la movilidad molecular en la interfaz metal-molécula.
Principales métodos:
- Utilizando alcanetiolos (octanedithiol, decanedithiol, dodecanedithiol) unidos a una superficie Au.
- Empleando microscopía de fuerza atómica conductora (AFM) con un contacto de oro superior presionado a fuerza constante.
- Realización de experimentos a temperatura ambiente y una temperatura elevada de 60 grados C.
Principales resultados:
- Se observó con éxito la conmutación estocástica de conductividad de encendido-apagado en octaneditiolo, decaneditiolo y dodecaneditiolo en Au{111}.
- La conmutación persistió incluso bajo una fuerza constante aplicada por la punta del AFM.
- La tasa de conmutación aumentó significativamente a 60 grados C.
- Los cambios electrónicos moleculares internos y la ruptura de contacto superior fueron descartados como causas primarias.
Conclusiones:
- La conmutación estocástica observada en los alcanetiolos se atribuye a la movilidad inherente de las moléculas atadas a la superficie del oro a través de enlaces de tiol.
- Esta movilidad molecular en la interfaz metal-molécula es un factor clave en la conmutación de la conductividad.
- Los hallazgos proporcionan una comprensión fundamental de los mecanismos de conmutación en la electrónica molecular.
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