Compared to bulk materials, atomically thin two dimensional materials are unique in that both electronic band structure and chemical potential can be tuned in situ by electric field.
Therefore optical studies in such systems greatly benefit from modern micro-facbrication technique and electric control of the material properties.
We also introduce new computational approaches to make these calculations much faster and more realistic, and we show, for instance, that even the substrate that holds these materials in experiments can dramatically influence the measured properties. Yingbo Zhao Advisor: Professor Omar Yaghi, Department of Chemistry Reticular Chemistry of Mesoscopic Constructs, Glasses, and Weaving Materials Zhao’s dissertation focuses on the development of reticular chemistry, where molecular building blocks are linked into extended frameworks using strong bonds, in the context of nanomaterial design.
Specifically, the dissertation advances the frontier of reticular chemistry is three aspects: (a) bringing metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), the products of reticular chemistry, into nanometer size regime and integrating them into mesoscopic constructs; (b) developing reticular chemistry beyond crystalline materials and synthesizing glassy form of MOFs; (c) Designing woven frameworks where interlacing molecular threads form crystalline three-dimensional frameworks.
CSL seeks to leverage excellence in disciplinary research to have a societal impact through interdisciplinary solutions that address major societal problems.
Detailed Business Plan Example - Phd Thesis Prize
The CSL Ph D Thesis award is bestowed annually to a researcher whose Ph D thesis makes advances in a disciplinary area that has an interdisciplinary angle.Because most of these effects only occur in the subdiffractional scale, I develop a nearfield scanning tunneling microscopy with a super-resolution to observe these 'dark' effects.In the study of 2D TMDC, I discover several excitonic states are originated from a very large exciton binding energy in the unique 2D semiconducting material.Using another nonlinear optical probe, second harmonic generation spectroscopy, I further identify an edge response at the domain boundary of a continuous TMDC crystal synthesized by the chemical vapor deposition technique.Finally, a TMDC exciton based light emitting device is demonstrated as a practical application.These developments not only provide a series of porous building blocks for nanomaterial design, but also lead to energy related applications such as electrochemical carbon dioxide reduction. Kelsey Sakimoto Advisor: Professor Peidong Yang, Department of Chemistry Inorganic-Biological Hybrids for Solar-to-Chemical Production Converting sunlight to chemicals in an efficient, reliable, and inexpensive manner is a grand challenge of the century.My thesis sheds some light on a potential approach, combining high efficiency semiconductor based light harvesters, and higher performance biological catalysis for CO2 fixation.In order to give unbiased predictions of how these systems behave, we use theoretical frameworks that do not rely on experimental fitting parameters, and use supercomputers to perform calculations.We show that many of these interesting electronic and optical properties stem from the weak electronic screening in these materials, which a result of their reduced dimensionality and which often cannot be accounted for with simpler models.The studied systems are consisted of two parts: artificlal plasmonic antennas and natural two dimensional transiiton metal dichalcogenides (TMCDs).With plasmonic antennas, I realize the classical analog of a few intriguing quantum mechanical effects, including electromagnetic induced transparency, anti-Hermitian coupling induced super-radiance, and spin Hall effect for photon.