Single Molecule Quantum State Switching with AFM Tip

C. Chotsuwan and S. C. Blackstock*

This figure illustrates the quantum state switching of a single 5PD molecule in a polymer film.  The polyredox molecule 5PD has 11 assessable and chemically stable charge states (0-+10) as determined electrochemically in solution.  When diluted in a thin polymer film, individual 5PD molecules can be reversibly switched to various charge states by contact with a biased AFM tip.  The 5PD charge state is monitored by Kelvin probe microscopy (KPM) via its associated surface potential. This result constitutes controlled quantum charge state switching in a discrete 3 nm3 volume that is the 5PD molecule in a thin film.