Our laboratory focuses on the science and applications of nanocrystals, especially semiconductor nanocrystal (aka  quantum dots). Our research ranges from the very fundamental to applications in electro-optics and biology. There is an ongoing synthetic effort underlying all of this to address the challenges of making new compositions and morphologies of nanocrystals and nanocrystal heterostructures, and new ligands so that the nanocrystals can be incorporated into hybrid organic/inorganic devices, or biological systems. The fundamental spectroscopic focus is largely at the single dot level, were we are currently developing methods for probing the dynamical properties of the electronic structure of dots at time scales between 100 psec and 1 msec. We are also investigating the physics of multiexcitons in various quantum dots using both ensemble time resolved methods, as well as single quantum dot correlation spectroscopies. We are studying the charge transport properties of films of dots or dot/organic hybrids, within our group and with collaborators. These fundamental transport properties are critical for designing devices like electrically quantum dot based driven light emittiers, lasers, photodetectors and photovoltaics. We are studying these three classes of devices, also within our group and with collaborators. On the biology and biomedical side, we are collaborating with a number of biology and medical groups to design nanocrystal probes that meet specific challenges. These include nanocrystals that selectively bind to single receptors on cell surfaces for tracking applications, creating “smart” nanocrystals that sense analytes to report back on concentrations of species, including for example pH, which is important for following endocytotic pathways and tumor microenvironments, and systematic characterizations of the effect of size, morphology, charge, and other surface compositions, on the uptake (or clearance) of nanocrystals. This last information is critical for the design of nanocrystal probes as molecular imaging agents in vivo.

B. K.H. Yen, A. Günther, M. A. Schmidt, K. F. Jensen, M. G. Bawendi, “A Microfabricated Gas-Liquid Segmented Flow Reactor for High Temperature Synthesis: The Case of CdSe Quantum Dots,” Angew. Chem. Int. Ed.  44, 5447-5451 (2005).

B. Fisher, J.-M. Caruge, Y.-T. Chan, J. Halpert, M. G. Bawendi, “Multiexciton Fluorescence from Semiconductor Nanocrystals,” Chem. Physics 318, 71-81 (2005).

J. P. Zimmer, S.-W. Kim, S. Ohnishi, E. Tanaka, J. V. Frangioni and M. G. Bawendi, “Size Series of Small Indium Arsenide-Zinc Selenide Core-Shell Nanocrystals and Their Application to In Vivo Imaging,” J. Am. Chem. Soc. 128, 2526-2527 (2006).

D. N. Weiss, X. Brokmann, L. E. Calvet, M. A. Kastner, M. G. Bawendi, “Multi-island single-electron devices from self-assembled colloidal nanocrystal chains,” App. Phys. Lett. 88, Art. No. 143507 (2006).

V.J. Porter, T. Mentzel, S. Charpentier, M.A. Kastner, M.G. Bawendi, “Temperature-, gate-, and photo-induced conductance of close-packed CdTe nanocrystal films,” Phys. Rev. B 73, 155303 (2006).

X. Brokmann, M. G. Bawendi, L. Coolen, J. P. Hermier, “Photon Correlation Fourier Spectroscopy,” Optics Express 14, 6333-6341 (2006).

J. E. Halpert, V. J. Porter, J. P. Zimmer, M. G. Bawendi, “Synthesis of CdSe/CdTe Nanobarbells,” J. Am. Chem. Soc. 128, 12590-12591 (2006).

J. S. Steckel, Y. K. H. Yen, D. C. Oertel, M. G. Bawendi, “On the Mechanism of Lead Chalcogenide Nanocrystal Formation,” J. Am. Chem. Soc. 128, 13032-13033 (2006).

P. T. Snee, R. C. Somers, G. Nair, J. P. Zimmer, M. G. Bawendi, D. G. Nocera, “A Ratiometric CdSe/ZnS Nanocrystal pH Sensor,” J. Am. Chem. Soc.128, 13320-13321 (2006).

G. Nair, M. G. Bawendi, “Carrier multiplication yields of CdSe and CdTe nanocrystals by transient photoluminescence spectroscopy,” Phys. Rev. B 76, 081304(R) (2007).