Toward quantum-dot cellular automata units: thiolated-carbazole linked bisferrocenes
Valentina Arima, Matteo Iurlo, Luca Zoli, Susmit Kumar, Manuel Piacenza, Fabio Della Sala, Francesca Matino, Giuseppe Maruccio, R. Rinaldi, Francesco Paolucci, Massimo Marcaccio, Pier Giorgio Cozzi, Alessandro Paolo Bramanti · Nanoscale · 2011
Quantum-dot Cellular Automata (QCA) exploit quantum confinement, tunneling and electrostatic interaction for transistorless digital computing. Implementation at the molecular scale requires carefully tailored units which must obey several structural and functional constraints, ranging from the capability to confine charge efficiently on different 'quantum-dot centers'-in order to sharply encode the Boolean states-up to the possibility of having their state blanked out upon application of an external signal. In addition, the molecular units must preserve their geometry in the solid state, to interact electrostatically in a controlled way. Here, we present a novel class of organometallic molecules, 6-3,6-bis(1-ethylferrocen)-9H-carbazol-9-yl-6-hexan-1-thiols, which are engineered to satisfy all such crucial requirements at once, as confirmed by electrochemistry and scanning tunneling microscopy measurements, and first principles density functional calculations.