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...
Vinh Nguyen
The Internet of Things (IoT) holds immense promise for energy sustainability but has a critical limitation: traditional energy storage cannot meet the power, energy, and size requirements of devices that power the IoT. Batteries that utilize specialized 3D geometries can meet these requirements, but manufacturing these batteries is currently time-intensive, inflexible, and requires laborious post-process integration. I will address these limitations by developing a manufacturing workflow that can print customized, integrated energy storage on-demand. First, I will develop a specialized manufacturing platform with custom printheads and tools. I will use this platform to 3D print a customized battery using a single-step, automated procedure that simplifies...
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...
Yuhuan Meng
The goal of my research is to predict the degradation of encapsulated perovskite films and devices. Perovskite solar cells (PSCs) show potential for ultra-low manufacturing cost with high power conversion efficiency. However, the commercialization of PSCs is still uncertain given concerns about their stability. Previously, we showed how to predict the degradation of diffusion length in non-encapsulated MAPbI3 films over an extremely wide range of environment conditions using machine learning (ML). However, encapsulation is necessary for long service lifetimes. During the period of the award, I will collect a large dataset of degradation kinetics of encapsulated MAPbI3 and (FA,Cs)Pb(I,Br)3 perovskite films that includes in-situ optical transmittance along with video...
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...
Inhwan Ko
My research focuses on the consequences and origins of various local renewable energy conflicts. A growing number of local communities around the world are facing land-use conflicts surrounding renewable energy facilities, and they are creating barriers to the national clean energy transition. For instance, local renewable energy conflicts, if not properly resolved, can derail local renewable energy projects, translate into unfavorable electoral outcomes for clean energy transition policies, and contribute to the diffusion of policy barriers to renewable energy facilities. To understand these consequences, however, one must investigate why local renewable energy conflicts unfold in the first place. NIMBY (not-in-my-back-yard) explanation provides only a...
Ashlyn Kamin
Examples of electrically conductive metal–organic frameworks (MOFs) are rare, yet they show incredible promise for applications in electrocatalysis, advanced energy storage, and chemical sensing. My research focuses on combining the high conductivity, tunability, and porosity of these MOFs with the solution-processability of liquid crystals. To do this, we synthesize planar, π–d conjugated macrocycles that are equivalent to a single hexagonal pore in a conductive MOF. By simultaneously tuning the macrocycle’s core and periphery, we hope to stabilize liquid-crystalline phases that preserve the extremely high through-space conductivity (from π-π stacking) whilst introducing fluidity and stimuli-responsiveness. Advisor: Dianne Xiao - Chemistry...
Xiaoxiao Jia
Layered vanadium oxides have proven to be the most promising electrode materials for aqueous rechargeable batteries on account of their multiple valence states of vanadium and large interlayer spacing. However, capacity decay due to vanadium dissolution and structural instability remains a great challenge. Our prior research has revealed these problems can be mitigated by chemical pre-intercalation of metal cations with much enhanced power and energy densities as well as much improved energy conversion efficiency. But fundamental understandings are yet to be achieved, my next-step work includes a detailed study on effects of coordination, valences, electronegativity of those preinserted ions on the electronic and crystal...
Micaela Homer
Photocatalysis is valuable to clean energy research because it allows the storage of solar energy in stable, energy dense chemical bonds. Solution processability and ease of chemical modification make semiconductor nanostructures ideal candidates for applications in photoredox catalysis. The rate of charge transfer is an important benchmark in evaluating such a system. Spectroscopic measurements of charge transfer (picoseconds) are incommensurate with the timescale of typical photocatalytic reactions (minutes). Electrochemical experiments will be an attractive alternative for screening of photocatalytic systems when coupled with electrochemical modeling. Advisor: Brandi Cossairt - Chemistry...
Miguel González
My work seeks to study the advantages of the anisotropic nature and flexibility of composites to enable the passive morphing capabilities that improve the overall energy efficiency, structural capacity, and dynamic stability of Marine-Hydrokinetic (MHK) turbine blades used for flow kinetic energy harvesting. With the goal of establishing a comprehensive mechanical characterization of the MHK blades, careful design and testing of the blades will be carried out in order to account for the inherent load-dependent deformations and to avoid potential material failures and hydro-elastic instabilities (resonance, parametric excitations, divergence, flutter, buffeting, etc). By designing, manufacturing, modeling, testing, and analyzing these blades, my research will...