Surface chemistry plays a critical role in the properties of nanomaterials. Changing the material surface adjusts particle solubility, conductivity, stability, and luminescence, among other properties. Our research examines the surfaces and interfaces of nanomaterials from an inorganic chemistry perspective to give insight into their structure-function relationships on a microscopic level.
Doped nanomaterials for sensing
Synthesis of new doped nanomaterials allows exploration of new sensing mechanisms using dopant related properties. In the presence of an analyte, dopants may be reduced or oxidized changing the nanocrystal luminescence. The dopant can also act as a probe of the semiconductor surface. We are synthesizing new doped nanomaterials and studying their optical and redox properties to develop ratiometric reversible sensors for biological analytes.
New materials for efficient light harvesting and catalysis
Nanocrystals of III-V semiconductors absorb in the infrared and near-infrared and are thus attractive for solution processed solar cells. Using hybrid polymer-semiconductor nanocrystal composites as conductive “ink” engages the advantages of both organic and inorganic materials. Examination of energy and charge transfer processes affecting these organic-semiconductor systems can improve solar conversion and storage efficiencies, but the large variation in polymer-to-nanocrystal interactions make these systems difficult to study. We use organic-inorganic donor-acceptor systems as a platform to study and optimize energy and charge transfer on a molecular level.
Charge separation in semiconductor nanomaterials can be improved by formation of hetero- and asymmetric structures. Advancement of these materials requires reduction of variations in their size and composition. Through careful synthetic control we construct new materials composed of semiconductors, metals, and organic materials with unique, tailorable properties. Examination of how changes in their composition and morphology affect their electronic properties will aid in use of these materials in catalysis among other applications.
McLaurin, E. J.; Bradshaw, L. R.; Gamelin, D. R. “Dual-Emitting Nanoscale Temperature Sensors” Chem. Mater., 2013, 25, 1283-1292. Invited Review. http://dx.doi.org/10.1021/cm304034s
McLaurin, E. J.; Fataftah, M. S.; Gamelin, D. R. “One-Step Synthesis of Alloyed Dual-Emitting Semiconducting Nanocrystals” Chem. Commun., 2013, 49, 39-41. http://dx.doi.org/10.1039/C2CC36862E
Bradshaw, L. R.; Hauser, A.; McLaurin, E. J.; Gamelin, D. R. “Luminescence Saturation via Mn2+-Exciton Cross Relaxation in Colloidal Doped Semiconductor Nanocrystals” J. Phys. Chem. C, 2012, 116, 9300-9310. http://dx.doi.org/10.1021/jp300765y
McLaurin, E. J.; Vlaskin, V. A.; Gamelin, D. R. “Water-Soluble Dual-Emitting Nanocrystals for Ratiometric Optical Thermometry” J. Am. Chem. Soc., 2011, 133, 14978-14980. http://dx.doi.org/10.1021/ja206956t
Winter, M. B.; McLaurin, E. J.; Reece, S. Y.; Olea, C.; Nocera, D. G.; Marletta, M. A. “Ru-Porphyrin Protein Scaffolds for Sensing O2” J. Am. Chem. Soc., 2010, 132, 5582-5583. http://dx.doi.org/10.1021/ja101527r
McLaurin, E. J.; Greytak, A. B.; Bawendi, M. G.; Nocera, D. G. “Two-Photon Absorbing Nanocrystal Sensors for Ratiometric Detection of Oxygen” J. Am. Chem. Soc., 2009, 131, 12994-13001. http://dx.doi.org/10.1021/ja902712b
Stires, J. C.; McLaurin, E. J.; Kubiak, C. P. “Infrared spectroscopic determination of the degree of charge transfer in complexes of TCNE with methyl-substituted benzenes” Chem. Comm., 2005, 28, 3532-3534. http://dx.doi.org/10.1039/b504416b
Gamelin, Daniel R.; Vlaskin, Vladimir A.; Janssen, Nils; Beaulac, Rémi; McLaurin, Emily J.; Fataftah, Majed S. 2013. “Host-Guest Materials Having Temperature-Dependent Dual Emission” US 20130140506, filed May 14, 2012 and issued June 6, 2013.
Marletta, Michael A.; Winter, Michael B.; McLaurin, Emily J.; Reece, Steven Y.; Olea, Charles, Jr.; Nocera, Daniel G. 2011. “Heme-binding photoactive polypeptides and methods of use thereof” US 20110243849, filed April 2, 2010 and issued October 6, 2011.