(3bn) Controlling Light in Nanostructured Materials for Sustainability and Human Health

Research Interests:

Utilizing light smartly and efficiently can bring enormous benefits for fields such as clean water, sustainable energy, and human health. The goal of my research program will be to control light in nanometer-precision structured materials and devices for energy and biomedical applications, from smart materials to green processes, and novel biosensors. The initial research topics in my proposed program will include (1) Design of stimulated materials responding to the wavelength of light for smart temperature control; (2) Development of hierarchical structure materials to utilize solar energy effectively for high-efficient photocatalytic processes; and (3) Leveraging light-matter interactions in lattices of functionalized nanoparticles for high throughput and sensitive biological detection devices.

My postdoctoral work with Professor Teri W. Odom has focused on the design of metamaterials to exhibit on-demand properties and applications. It covers three different areas: (I) I developed a thermal annealing strategy that achieved record-narrow spectral linewidths of plasmon resonances from two-dimensional (2D) lattices of metal nanoparticles (NPs). Ultra-narrow surface lattice resonances (SLRs) with linewidths as narrow as 4 nm from arrays of Au, Ag, Al, and Cu NPs can be achieved for the first time. Besides annealing, I developed a modified chemical vapor deposition process to grow graphene on Cu NPs in lattices and produced graphene-encapsulated Cu NPs (Cu@G) lattices. Narrowest reported SLR linewidths (2 nm) were achieved from these Cu@G NP lattices and were stable for months. These record-high-quality plasmonic lattices can offer promising platforms in studies of light–matter interactions ranging from photochemistry to biosensing, and nonlinear physics. I further demonstrated that the graphene layer could enhance nanolasing from metal NPs lattices by providing aromatic-aromatic interactions between graphene and dye molecules, which introduced a new strategy to tune the plasmonic lasing by designing the surface chemistry of metal NPs. (II) I also developed a scalable approach to achieve spatially selective graphene functionalization. Chemical reactivity of a functionalization process on graphene could be tuned by changing its local curvature. By patterning areas of graphene nanowrinkles and crumples followed by a single-process plasma reaction, I achieved graphene with regions having different fluorination levels. Notably, I found that the conductivity of the functionalized graphene nanostructures could be locally tuned as a function of feature size without affecting the mechanical properties. These results bring wide applications in ultrathin electronic and optoelectronic devices based on graphene but also open possibilities for tuning local properties of other 2D nanomaterials and thin films. (III) I developed the Cu-Pt core-shell NP lattices that show wavelength-selective photocatalytic effect in the visible-IR range of solar light. I tuned the periodicity, core size, and thickness of the shell of Cu-Pt NPs to precisely control the wavelength of resonances for photocatalysis. The designed lattices showed high catalytic reactivity in the near-infrared range, which can significantly enhance the effective utilization of solar energy.

My graduate work with Professor Vikas Berry has focused on the structure design of the 2D nanomaterials, and it consists of three parts: (I) I developed several approaches to introduce controlled nanowrinkles in two-dimensional nanomaterials. Specifically, I introduced nanoscale graphene wrinkles via bacteria shrinkage process and demonstrated an anisotropic carrier transport in wrinkled graphene devices for the first time. I also revealed that electronic and optoelectronic modifications of a single wrinkle in the molybdenum disulfide (MoS₂) flake from the design of wrinkled MoS₂ electronic devices. (II) I built a new energy model of wrinkled thin films to investigate the adhesion energy at the interface between two-dimensional nanomaterials and rigid substrates. (III) I demonstrated the fabrication of large scale nanowrinkles in thin metal films and proposed a mathematic model to explain the formation mechanism of hierarchical wrinkle patterns.

Teaching Interests:

I was a teaching assistant for various chemical engineering courses, including Transport Phenomena, Process Control, Basic Concepts in Materials Science and Engineering, Fundamental of Electrical Properties, and Fundamental of Mechanical Properties, where I worked closely with students by leading discussion sections and receiving feedback about teaching performance. Given my training (both B.S. and Ph.D. in chemical engineering), I believe I am prepared to teach all the core courses in chemical engineering. I am also enthusiastic about developing cross-discipline senior/graduate-level courses and seminars centered on chemical vapor deposition, thin-film electronics, nanofabrication, materials behavior, solid mechanics, nanophotonics, plasmonics, etc. To broaden the graduate course offerings, I will also develop a graduate-level special topics course on low-dimensional materials and metamaterials, which will span coverage from dimension reduction of materials, to fundamental mechanical concepts and device physics, and the discussion of emerging applications such as flexible electronics, photocatalysts, and single-molecule detectors.

Selected Publications:

1. S. Deng, G. Kang, J. Guan, P. Choo, J.-E. Park, R. Li, G. C. Schatz, and T. W. Odom*, “Aromatic-aromatic Interactions Enhanced Nanolasing”, In preparation, 2020.
2. S. Deng, B. Zhang, P. Choo, P. Smeets, and T. W. Odom, “Wavelength Selective Photoelectrocatalysis in Copper-platinum Core-shell Nanoparticle Lattices”, In preparation, 2020.
3. S. Deng, R. Li, J-E. Park, J. Guan, P. Choo, J. Hu, P. Smeets, and T. W. Odom, “Ultra-narrow Plasmon Resonances from Annealed Nanoparticle Lattices”, Proceedings of the National Academy of Sciences, In revision.
4. S. Deng, D. Rhee, W.-K. Lee, S. Che, B. Keisham, V. Berry, T. W. Odom, “Graphene Wrinkles Enable Spatially Defined Chemistry”, Nano Letters, 2019, 19, 5640.
5. S. Deng, E. Gao, Y. Wang, S. Sen, S. T. Sreenivasan, S. Behura, P. Král, Z. Xu, V. Berry, “Confined, Oriented, and Electrically Anisotropic Graphene Wrinkles on Bacteria”, ACS Nano, 2016, 10, 8403.
6. S. Deng, V. Berry, “Wrinkled, Rippled and Crumpled Graphene: An Overview of Formation Mechanism, Electronic Properties, and Applications”, Materials Today, 2016, 19, 197.
7. S. Deng, A. V. Sumant, V. Berry, “Strain Engineering in Two-dimensional Nanomaterials Beyond Graphene”, Nano Today, 2018, 22, 14.
8. S. Deng, V. Berry, “Increased Hierarchical Wrinklons on Stiff Metal Thin Film on a Liquid Meniscus”, ACS Applied Materials & Interfaces, 2016, 8, 24956.
9. S. Deng, E. Gao, Z. Xu, V. Berry, “Adhesion Energy of MoS₂ Thin Films on Silicon-based Substrates Determined via the Attributes of a Single MoS₂ Wrinkle”, ACS Applied Materials & Interfaces, 2017, 9, 7812.
10. S. Deng, S. Che, R. Debbarma, V. Berry, “Strain in a Single Wrinkle on an MoS₂ Flake for in-Plane Realignment of Band Structure for Enhanced Photoresponse”, Nanoscale, 2019, 11, 504.