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Brett A. Helms
Staff Scientist, Organic and Macromolecular Synthesis
Brett A. Helms received his B.S. (2000) from Harvey Mudd College and his Ph.D. (2006) with Jean M. J. Fréchet at the University of California, Berkeley. He joined the staff of the Molecular Foundry in 2007, after postdoctoral research at the Technische Universiteit Eindhoven with E. W. (Bert) Meijer. His research interests include structure of and reactivity at nanocrystal surfaces and assembly of functional mesomaterial systems using block copolymers.
Dr. Helms' research program is devoted to precision chemical synthesis and assembly of functional mesoscale materials from organic, organometallic, polymeric and nanocrystalline building units. Enhanced capabilities relevant to energy and biology are enabled by unique approaches to the modular design of their architectures and interfaces.
Multicomponent Hierarchical Mesoscale Materials
Assembly of Nanocomponents into Hierarchically Ordered Mesoscale Materials
I view recent discoveries in the exciting and unusual physical properties of both organic and inorganic nanoscale building blocks as only the beginning of the transformative era in science. I seek to further harness these compositionally disparate materials synergistically into robust new materials for advanced technologies. However, these components require "blue prints" – that is to say, exogenous agents – that contain instructions on how they will assemble, interface and ultimately function. Given their well-defined and controllable chemistries and architectures, polymers and small molecules are uniquely suited for this task.
Read full research paper
Chemistry of Nanocrystal Surfaces
Molecular Level Control over Function from Naked Nanocrystals to Nanocrystal Networks
The surface chemistry of colloidal nanocrystals dominates their physical properties in energy devices and in a biological milieu. To build a foundational understanding of the impact of various surface constituents on properties of interest, I focus on the synthetic development of chemical methodologies to re-surface them with constituents of broad compositional diversity, spanning polymeric, main group and transition metal species. Read full research paper
- Deng, Y. X.; Josberger, E.; Jin, J. H.; Helms, B. A.; Zhong, C.; Anantram, M.P.; Rolandi, M. "H+-type and OH– -type biological protonic semiconductors and complementary devices" Scientific Reports 2013, 3, 2481. [pdf]
- Milliron, D. J.; Buonsanti, R.; Llordes, A.; Helms, B. A. "Constructing Functional Mesostructured Materials from Colloidal Nanocrystal Building Blocks" Acc. Chem. Res. Articles ASAP. DOI: 10.1021/ar400133k [pdf]
- Rivest, J.B.; Buonsanti, R.; Pick, T.E.; Zhu, L.; Lim, E.; Clavero, C.; Schaible, E.; Helms, B.A.; Milliron, D.J. "Evolution of Ordered Metal Chalcogenide Architectures through Chemical Transformations" J. Am. Chem. Soc. 2013, 135, 7446-7449. [pdf]
- Duong, J. T.; Bailey, M. J.; Pick, T. E.; McBride, P.M.; Rosen, E. L.; Buonsanti, R.; Milliron, D. J.; Helms, B. A. "Efficient Polymer Passivation of Ligand-Stripped Nanocrystal Surfaces" J. Polym. Sci. A Polym. Chem. 2012, 50, 3719-3727. [pdf]
- Buonsanti, R.; Pick, T. E.; Krins, N.; Richardson, T. J.; Helms, B. A.; Milliron, D. J. "Assembly of ligand‐stripped nanocrystals into precisely controlled mesoporous architectures" Nano Lett. 2012, 12, 3872-3877. [pdf]
- Chahal, D. S.; Chahal, H. S.; Bayles, A. R.; Rudié, E. N.; Helms, B. A. "Synthetic Development of Cell-Permeable Polymer Colloids Decorated with Nanocrystal Imaging Probes Optimized for Cell Tracking" Chem. Sci. 2012, 3, 2246-2251. [pdf]
- Albers, A. E.; Chan, E. M.; McBride, P. M.; Ajo-Franklin, C. M.; Cohen, B. E.; Helms, B. A. "Dual-Emitting Quantum Dot/Quantum Rod-Based Nanothermometers with Enhanced Response and Sensitivity in Live Cells" J. Am. Chem. Soc. 2012, 134, 9565-9568. [pdf]
- Rosen, E. L.; Buonsanti, R.; Llordes, A.; Sawvel, A. M.; Milliron, D. J.; Helms, B. A. "Exceptionally Mild Reactive Stripping of Native Ligands from Nanocrystal Surfaces by Using Meerwein's Salt" Angew. Chem. Int. Ed. 2012, 51, 684-689. [pdf]
- Hourani, R.; Zhang, C.; van der Weegen, R.; Ruiz, L.; Li, C.-Y.; Keten, S.; Helms, B. A.; Xu, T. "Processable Cyclic Peptide Nanotubes with Tunable Interiors" J. Am. Chem. Soc. 2011, 133, 15296-15299. [pdf]
- Voet, V. S. D.; Pick, T. E.; Park, S.-M.; Moritz, M.; Hammack, A. T.; Urban, J. J.; Ogletree, D. F.; Olynick, D. L.; Helms, B. A. "Interface Segregating Fluoralkyl-Modified Polymers for High-Fidelity Block Copolymer Nanoimprint Lithography" J. Am. Chem. Soc. 2011, 133, 2812-2815. [pdf]
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