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Andrei Draguicevic

I'm a second-year graduate student in the Velian lab, where I'm working on heterogenous single-site catalysts for environmentally relevant reactions. My research is focused on using black phosphorus, a 2D van der Waal material, to support single metal atoms to create distinct and tunable active sites on a heterogenous support. Currently, I am using hydroformylation as a test reaction to probe this system, where Rh atoms are supported onto the black phosphorus surface to catalytically convert olefins into aldehydes. Advisor: Alexandra Velian - Chemistry...

Hannah Contreras

Highly efficient, financially feasible solar photovoltaic technology is crucial to the global transition from fossil fuels to renewable energy to mitigate climate change. Perovskite solar cells (PSCs) represent a promising next generation technology; they have already matched the efficiency of the current market-dominant silicon technology in just a decade of research. Widespread, viable commercial application of PSCs requires stable, scalable device structures to maintain efficiency over time. My goal is to enhance PSC stability and efficiency by studying charge carrier recombination and defect dynamics in the charge transport and active layers of PSCs through extensive device fabrication and subsequent spectroscopic characterization. Advisor: David Ginger -...

Matthew Chang

Information and communications technology (ICT) is predicted to comprise 30% of the world's total energy consumption by 2030.  Because of the increasing demand in telecommunications and other relevant technologies, more efficient nanophotonic devices will need to be made industrially.  One such device is the Faraday isolator, an optical device that allows the transmission of light in one direction while blocking it in the opposite direction.  Yttrium iron garnet (YIG) is a staple ferrimagnetic Faraday isolator material.  However, the processability of YIG is lacking due to it mainly being grown as a single crystal.  Currently, I am in the process of perfecting a hydrothermal synthesis...

Tyson Carr

I research the fundamentals of anode-electrolyte interactions in Li-ion batteries, in order to enable use of high-capacity, next-generation alloying electrode materials. Standard graphite anodes have up to an order of magnitude lower theoretical capacity than alloying materials such as silicon. However, the volume expansion in these materials as they store lithium ions causes the capacity to fade as they are charged and discharged. My research specifically involves modifying the electrode interface to dynamically mitigate the effects of the volume expansion, while still allowing reversible lithium ion storage to proceed. While the current model system is with silicon electrodes, my research will inform adaptation of...

Madeleine Breshears

My research focuses on merging data science and machine learning techniques with functional scanning probe microscopy (SPM) to better understand energy materials. We are currently experiencing a convergence of advancement in both data science techniques and scanning probe microscopy resolution and functionality. I aim to take advantage of this confluence to evaluate the spatial heterogeneity of photovoltaic materials. SPM allows us to visualize surface photovoltage, charging rate, chemical composition, and morphology on the nanometer scale. These multimodal techniques produce incredibly dense, multidimensional data that naturally encourage the use of machine learning to extract meaningful information more efficiently. Specifically, I am working on using neural...

Eden Tzanetopoulos

Lighting accounts for 15% of annual global energy consumption. Due to mounting concerns arising from anthropogenic climate change, there is an increased demand for lighting technologies with higher efficiencies and greater longevity. My research will focus on synthesizing colloidal nanocrystals of Mn4+-doped A2MF6 (A = K, Na, Cs; M = Ti, Ge, Zr) lattices to be used as red-emitting phosphors. These activator-host materials can act as an efficient red component of white LEDs due to their narrow-band ~630 nm emission. Mn4+-doped fluorides have recently been utilized in next-generation lighting technologies, but the nanoscale regime that affords synthetic tunability and narrow emission bandwidth has yet to...

Kathleen Snook

Electrically conductive metal–organic frameworks (MOFs) are important due to their applications in electrocatalysis, energy storage, and electronic devices. However, their synthesis is often poorly developed, resulting in small crystal sizes and a limited understanding of their physical properties. I hypothesize that a critical barrier to their synthesis is uncontrolled ligand oxidation, as conductive MOFs often contain air-sensitive catechol, o-phenylenediamine, and dithiolene building units. During this award period, I will examine the synthesis of π–d conjugated 2D frameworks, an important family of conductive MOFs, via controlled chemical oxidation in an inert atmosphere. I will optimize my synthetic parameters using a design of experiments approach, in...

Yangwei Shi

I will focus on fabrication and characterization of organic-inorganic halide perovskite solar cells which are regarded as a promising photovoltaic technology. My projects include passivation of mixed cation mixed halide wide-bandgap perovskite, aiming to improve the photoluminescence quantum efficiency of perovskite and to achieve a higher open-circuit voltage that approaches the theoretical limit. In addition, I will focus on developing a solution processed recombination layer with matched refractive index and good conductivity for tandem perovskite/silicon solar cell. Based on the low defect density of wide bandgap perovskite and solution processible recombination layer, the efficiencies of tandem perovskite/silicon solar cells can be further increased. Advisor:  David...

Ricardo Rivera-Maldonado

Electrocatalysis is a promising means to reduce the climate impacts of the chemical industry by combining renewable electricity, abundant feedstocks, and catalysts made of earth-abundant materials. The study of the surface of electrocatalytic materials is essential for the advancement of the field since all inner-sphere reactions occur at the surface and the surface modulates charge transfer and outer-sphere interactions with solvents, electrolytes, and substrates. Nanoscale catalysts enable these studies due to their high surface-to-bulk atom ratio. My research involves studying transition metal phosphide (TMP) nanoparticles. TMPs have been shown to be excellent catalysts for hydroprocessing and hydrogen evolution, which provide a foundation for developing...

Ramsess Quezada

Organic Mixed Ionic Electronic Conductors (OMIECs) are a set of organic semiconducting materials that conduct both electronic and ionic charge in an electrolyte. When OMIECs are electrochemically oxidized or reduced, counter-ions will enter the film to compensate the electronic charge. This process of ion injection is a crucial one for the optimization of these materials in applications such as organic batteries and capacitors. My research will focus on probing and understanding the electrochemical and electrostatic relationship between these charges in conjugated polymers. Utilizing a wide range of characterization techniques, including XRD and AFM, I will investigate the physical relationship between these electronic and ionic...

Christine Morrison

Conjugated polymers are touted for their electronic and photonic properties, and have been shown to have significant applications in light-harvesting and storage. Much research has already been done showing the plethora of applications for conjugated polymers, but there has been considerably less work involving conjugated cyclic polymers. My research is focused on creating an optimized initiator for ring expansion metathesis polymerizations (REMP) for use in the synthesis of conjugated cyclic polymers. Ring expansion polymerizations are a favorable way to approach the production of cyclic polymers as they provide better control over molecular weight, effective conjugation length, and long-range morphology of the polymer. Using REMP...

Sebastian Krajewski

My research is centered on the synthesis and design of atomically defined nanoclusters that act as clean energy catalysts. The aim is to study the catalyst-support interface in catalytic systems by utilizing metal chalcogenide clusters that feature transition metal edge sites. This serves as a model for heterogeneous catalysts, which themselves are resistant to precise characterization and mechanistic elucidation. I will synthesize and study compounds that feature a cobalt selenide core with pendant organic ligands, aiming to construct a pocket on the surface of the cluster where transition metals may bind. Studying the behavior of earth-abundant metals such as iron and cobalt in this system via methods...