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...
Daphne Garcia
The focus of my research is to develop new electrode materials for energy storage devices by improving current chemical processes of dealloying brass sheets to create three-dimensional nanoporous copper structures. By controlling the dealloying process, a more even distribution of pores that are all less than a micron in diameter and greater surface area in the structure will be achieved. These structures will function as current collectors in lithium-ion batteries, with the potential for higher energy density, increased cyclic performance and rate kinetics. Variables such as dealloying chemical composition, brass composition, and sheet thickness will be analyzed to identify the ideal conditions for achieving...
Diwash Dhakal
Rechargeable batteries are among the candidates that can fulfill the evolving energy storage needs and are being researched extensively. My research focuses on the application of X-ray spectroscopy techniques to better understand the critical processes in rechargeable Zn-ion batteries (ZIBs). Specifically, I am looking at the local chemical environment and coordination complex in electrolytes and ion pairing in the electric double layer at electrode interfaces. Such a study will lead to a better understanding of the role of ion pairing on both structure and dynamics at the electrode-electrolyte-interface, a key question for ZIBs and many other battery systems. Advisors: Gerald T. Seidler, Guozhong Cao -...
John Cenker
Two-dimensional van der Waals crystals hold great promise for future devices due to their atomically thin nature and the consequent unique emergent physics. Furthermore, their pristine crystal lattices should make them extraordinarily robust to external stresses such as strain. My research focuses on developing new ways to apply strain to 2D materials to drive phase transitions which can be harnessed for future device applications. For example, applying strain to atomically thin magnets to drive magnetic phase transitions. This research could enable energy-efficient, ultrathin memory bits which can be written purely by an applied voltage to the strain cell. Advisor: Xiaodong Xu - Physics...
Christian Pederson
Simulating novel materials with the desired range of properties for efficient solar energy collection, or storage is computationally intractable with classical computers. Quantum computers and simulators are the only known devices that can efficiently tackle these problems, yet are plagued by the experimental challenges of scaling up sensitive quantum systems. I will investigate an integrated photonics platform based on point defects in diamond. Significant challenges remain, but integrated devices have a clear path to scalability since they build upon existing semiconductor fabrication methods. Recent work demonstrated that a particular defect, the silicon-vacancy(SiV) center, could be created nanometers from the surface of diamond without compromising its...
Jiaying Yang
Electrocatalytic conversion of CO2 into useful chemical resources is a compelling strategy to mitigate the effects of climate change, but accomplishing this goal requires the development of next-generation catalysts. Highly selective homogeneous catalysts suffer from low stability, while robust heterogeneous catalyst cannot be easily tuned for selectivity. Immobilization of molecular catalysts on heterogeneous supports provides more robust catalytic systems with high selectivity and activity. Through my research, I will investigate the surface functionalization of phosphorene, a two-dimensional phosphorous analogue of graphene with a thickness dependent bandgap. The support was chosen because it can be viewed as a solid-state phosphine ligand poised to coordinate to transition metal...