Robert M. Dickson Professor Office: MSE G209A Phone: 404-894-4007 Fax: 404-894-7452 E-mail Robert M. Dickson My CV

B.A., Haverford College, 1991; Ph.D., University of Chicago, 1996.

Research Corporation Research Innovation Award - 1999; NSF CAREER Award - 2000; Alfred P. Sloan Research Fellow - 2001; Appointed as the Blanchard Assistant Professor of Chemistry - 2001; Camille Dreyfus Teacher-Scholar Award - 2002, Visiting Lecturer, National Science Council, Taiwan - 2003, Outstanding Achievement in Research Program Development Award - 2006

Research Interests

Dr. Dickson's group is developing novel single molecule methods for the study of intermolecular interactions in biological and materials systems. By directly imaging anisotropic dipolar single molecule emission and modeling expected emission patterns, we have developed the world's only methods for determining true 3-D single molecule orientations. Since each molecule interacts differently with its surroundings, great diversity is observed in molecular behaviors. For example, single molecules in polymeric matrices exhibit surprising rotational mobilities that are indicative of nanoscale polymer dynamics. Such molecular orientational studies directly probe both biological and materials systems to provide greatly enhanced understandings of their dynamics.

Single Molecule Biophysics. Having observed orientation-dependent interactions of fluorescently labeled, single proteins, precise studies of biological mechanisms are performed. Unfortunately, standard fluorescent labels are often unsuitable for long-time single molecule imaging, especially in living systems. Thus, in order to make single molecule methods more accessible, we are developing Au and Ag nanoclusters as a new class of fluorescent labels in biology. These high brightness, robust nanomaterials should enable direct labeling of proteins to image live cells, study protein-protein interactions, and potentially watch individual proteins as they fold to their native conformations. Au and Ag nanoclusters exhibit discrete excitation and emission due to being composed of only a few atoms. Consequently, with size-tunable optical properties and absoprtion comparable to semiconductor quantum dots, but with improved photostability, these nanoclusters offer new opportunities in biological labeling. For example, the extremely small size will be less invasive; noble metals are not toxic; and their discrete energy levels enable energy transfer experiments to be performed—all with weak mercury lamp illumination on the single molecule level. Much brighter and more robust than organic dye molecules, these advanced inorganic nano-materials are being utilized both as optical memory elements and as photo-activated biological labels.

Optical Properties of Individual Nanoparticles. We have created and are currently studying the properties of extremely brightly fluorescing photo-activated nanoparticles . Much brighter and more robust than organic dye molecules, these advanced inorganic nano-materials are being utilized both as optical memory elements and as photo-activated biological labels.

Single Molecule Electroluminescence. We have created the first electroluminescent single molecules/nanoclusters at room temperature. The discrete energy levels of these 2-20 atom nanoclusters yield molecular emission with color being indicative of nanocluter size. Employing negative differential resistance-like behavior in the EL, we have created single molecule LEDs, single nanocluster logic gates, and even a full adder constructed from only two nanoclusters. We are currently studying the charge injection into different nanoclusters to characterize the interfaces crucial to all nanoscale/molecular electronics and optoelectonics devices.

Recent Publications

J. Yu, S. Choi, and R. M. Dickson, “Shuttle-based fluorogenic silver cluster Biolabels”, Angew. Chem. Int. Ed., 48, 324-326, (2009).

S. A. Patel, C. I. Richards, J.-C. Hsiang, and R. M. Dickson, “Water-soluble Ag Nanoclusters Exhibit Strong Two-Photon-induced Fluorescence”, J. Amer. Chem. Soc., 130, 11602-11603 (2008).

J. Yu, S. Choi, C. I. Richards, Y. Antoku, and R. M. Dickson, “Live Cell Surface Labeling with Fluorescent Ag Nanocluster Conjugates”, Photochemistry and Photobiology, 84, 1435-1439, (2008).

C. I. Richards, S. Choi, J-C. Hsiang, Y. Antoku, T. Vosch, A. Bongiorno, Y.-L. Tzeng,  and R. M. Dickson, “Oligonucleotide-Stabilized Ag Nanocluster Fluorophores”, J. Amer. Chem. Soc., 130, 5038-9 (2008).

C. M. Ritchie, K. R. Johnsen, J. R. Kiser, Y. Antoku, R. M. Dickson, and J. T. Petty, “Ag Nanocluster Formation Using a Cytosine Oligonucleotide Template”, J. Phys. Chem. C, 111, 175 (2007).

J. Yu, S. A. Patel, and R. M. Dickson, “In vitro and Intracellular Production of Peptide-Encapsulated Fluorescent Silver Nanoclusters”, Angew. Chem. Int. Ed., 46, 2028-2030 (2007).

T. Vosch , Y. Antoku , J-C. Hsiang , C. Richards , J. I. Gonzalez, and R. M. Dickson, “Strongly Emissive Individual DNA-encapsulated Ag Nanoclusters as New Single Molecule Fluorophores”, Proc. Nat. Acad. Sci. USA 104, 12616-12621 (2007). 
   
J. Zheng, P. R. Nicovich, and R. M. Dickson, “Highly Fluorescent Noble Metal Quantum Dots”, Annual Review of Physical Chemistry, New Fluorescence Probes, 58, 409 (2007).

J. I. Gonzalez, T. Vosch, and R. M. Dickson, “Charge Injection into Discrete States of Individual Electroluminescent Au Nanoclusters”, Phys. Rev. B, 74, 235404 (2006).       

J. I. Gonzalez, T. Vosch, and R. M. Dickson, “Asymmetric Electrode-Molecule Transport Dynamics Tracked by Nanoscale Electroluminscence”, Phys. Rev. B, 74, 064305 (2006).

L. A. Peyser-Capadona, J. Zheng, J. I. Gonzalez, T.-H. Lee, S. A. Patel, and R. M. Dickson, “Nanoparticle-Free Single Molecule Anti-Stokes Raman Spectroscopy”, Phys. Rev. Lett. 94, 058301 (2005).

T-H. Lee, J. I. Gonzalez, J. Zheng, and R. M. Dickson “Single molecule optoelectronics”, Accounts Chem. Res., 38, 534-541 (2005).

J. I. Gonzalez, T.-H. Lee, M. D. Barnes, Y. Antoku, and R. M. Dickson, “Quantum mechanical single-gold-nanocluster electroluminescent light source at room temperature”, Phys. Rev. Lett., 93, 147402 (2004).

J. Zheng, C. Zhang, and R. M. Dickson, “Highly fluorescent, water-soluble, size-tunable gold quantum dots”, Phys. Rev. Lett., 93, 077402(2004).

T.-H. Lee and R. M. Dickson, “Nanocomputing with Nanocrystals”, Optics and Photonics News, 15, 22-27 (2004).

J. T. Petty, J. Zheng, N. V. Hud, and R. M. Dickson, “DNA Templated Ag Nanocluster Formation”, J. Amer. Chem. Soc., 126, 5207-5212 (2004).

P. Kumar, T.-H. Lee, A. Mehta, B. G. Sumpter, R. M. Dickson, and M. D. Barnes, “Photon antibunching from oriented semiconducting polymer nanostructures”, J. Amer. Chem. Soc., 126, 3376-3377 (2004).

J. Zheng, J. T. Petty, and R. M. Dickson, “High Quantum Yield Blue Emission from Water-Soluble Au8 Nanodots”, J. Amer. Chem. Soc., 125, 7780-7781 (2003).

T.-H. Lee, C. R. Hladik, and R. M. Dickson, “Asymmetric photoconductivity within nanoscale break junctions”, NanoLett., 3, 1561-1564 (2003).

T.-H. Lee and R. M. Dickson, "Discrete two-terminal single nanocluster quantum optoelectronic logic operations at room temperature", Proc. Nat. Acad. Sci. USA, 100, 3043-3046 (2003).

J. Zheng and R. M. Dickson, “Individual Water-Soluble Dendrimer-Encapsulated Silver Nanodot Fluorescence”, J. Amer. Chem. Soc., 124, 13982-13983 (2002).

T.-H. Lee, J. I. Gonzalez, and R. M. Dickson, “Strongly Enhanced Field Dependent Single Molecule Electroluminescence”, Proc. Nat. Acad. Sci. USA, 99, 10272-10279 (2002).

A. P. Bartko, K. Xu, and R. M. Dickson, “Three-Dimensional Single Molecule Rotational Diffusion in Glassy State Polymer Films”, Phys. Rev. Lett., 89, 026101/1-026101/4 (2002).

L. A. Peyser, A. E. Vinson, A. P. Bartko, and R. M. Dickson, “Photoactivated Fluorescence from Individual Silver Nanoclusters”, Science, 291:103-106 (2001).

R. M. Dickson and L. A. Lyon, “Unidirectional Plasmon Propagation in Metallic Nanowires”, J. Phys. Chem. B, 104, 6095-6098 (2000).

A. P. Bartko and R. M. Dickson, “Imaging Three-Dimensional Orientations of Single Molecules”, J. Phys. Chem. B, 103, 11237-11241 (1999).

A. P. Bartko and R. M. Dickson, “Three-Dimensional Orientations of Polymer-Bound Single Molecules”, J. Phys. Chem. B 103, 3053-3056 (1999).
     
R. M. Dickson, A. B. Cubitt, R. Y. Tsien, and W. E. Moerner, “On/Off Blinking and Switching Behaviour of Single Green Fluorescent Protein Molecules”, Nature, 388, 355-358 (1997).

R. M. Dickson, D. J. Norris, Y. L. Tzeng, and W. E. Moerner, “Three Dimensional Imaging of Single Molecules Solvated in the Pores of Polyacrylamide Gels”, Science. 274, 966-969 (1996).