Presentación Oral Invitada: "Study of conjugated polymer nanocapacitors: possible application as memory elements"

PALACIOS, RODRIGO E.; FRADKIN, LEONID; LEE, KWANG-JIK; BOLINGER, JOSHUA C.; BARBARA, PAUL F.

Rio de Janeiro, Brasil

Conferencia; NANO - 2008 - 9th Internacional Conference on Nanostructured Materials; 2008

Centro Brasileiro de Pesquisas Físicas

Hole-injection in individual MEH-PPV molecules and nanoclusters was studied using the recently developed Fluorescence-Voltage Single Molecule Spectroscopy (F-V SMS) technique [1,2]. Charge-injection into MEH-PPV single molecules, nanoclusters and films was performed in capacitor devices containing different types of hole-injection layers. Thermionic hole-injection was achieved in films and nanoclusters whereas for single molecules only light-induced hole injection was observed. These results indicate that the effective ionization potential (IP) of single MEH-PPV molecules is higher than that of the corresponding nanoclusters and film and suggest that molecular conformation and/or inter-chain interaction play a crucial role in controlling the IP of the polymer material. During the light-induced charging/discharging of single molecules a fluorescence-voltage bi-stable behavior was observed. This behavior was exploited to produce a model single molecule memory device. The device demonstrates the potential use of conjugated polymers single molecules as memory elements which can be individually addressed and controlled by a combination of light and bias.