Research

Research Experience

Graduate Research Assistant                           2017 - 2022

Colorado State University, Fort Collins, CO 

Mentor: Professor James Neilson

Dissertation Title: Organic Cation Dynamics and Property Relationships in Layered Perovskite Derivatives

I used parts of the atom, called neutrons, to study the movement of organic molecules. I went to specialized facilities, like a national laboratories, that produce neutrons and have instruments capable of monitoring their energies. With this technique, I observed an increase in the white light (broadband) emission when the movement is slower and more restricted. This research provides a set of parameters for design principles of solid-state lighting devices for potential consumers. 

Undergraduate Laboratory Internship                                                                           2017

Lawrence Berkeley National Laboratory, Berkeley, CA  

Mentor: Dr. Mona Mirsiaghi 

Research Topic: Analysis of Free Fatty Acids in Waste Oil Sources

Waste oils can be used as potential additives in diesel fuel to increase domestic sustainability. I helped develop analytical techniques to separate different oils from one another making them easily distinguishable. These oils could then be tested in engines by blending them into diesel fuel by their respective companies for scale-up processes and easier integration into existing infrastructure.

Undergraduate Laboratory Internship                                                                                        2016

National Renewable Energy Laboratory, Golden, CO

Mentor: Dr. Craig Turchi

Research Topic: Phase Change Thermal Energy Carriers for Solar Industrial Process Heat Supply 

Solar power is a renewable energy source commonly seen in homes and electronics. Concentrating solar power is used on a larger scale (the roof of your home v. a football field). This type of solar power requires a thermal energy system (a material like a salt) that can hold the heat provided by the sun. I designed three thermal energy systems, determined a suitable salt, through literature search and lab testing, and completed a cost-benefit analysis to determine the most cost effective system. The cost-benefit analysis concluded that the costs of both solar field and thermal energy system would need to be lower to compete with natural gas prices. 

Visiting Faculty Program Undergraduate Participant                                                                                2015

Argonne National Laboratory, Lemont, IL

Mentor: Dr. Shannon Riha

Research Topic: Atomic Layer Deposition of Manganese Sulfide Thin Films for Applications in Energy Conversion and Storage 

Atomic layer deposition is a synthesis technique that takes gaseous materials and layers them on top of one another at the atomic level creating a solid surface. We used this technique to deposit a binary metal sulfide, MnS, as a thin film. We determined a mechanism for the layering and showed this material could be used in a battery. This work resulted in two publications.

Publications

(7) "Influence of Inorganic Layer Thickness on Methylammonium Dynamics in Hybrid Perovskite Derivatives." Alexandra A. Koegel, Iain I.W. Oswald, Chuy Rivera, Samantha L. Miller, M. Jewels Fallon, Timothy R. Prisk, Craig M. Brown, James R. Neilson. Chemistry of Materials. 2022. ASAP. [doi]

(6) "Temperature-induced structural transition in an organic-inorganic hybrid layered perovskite (MA)2PbI2-xBrx(SCN)2." Takuya Ohmi,   Tomoaki Miura, Kei Shigematsu, Alexandra A. Koegel, Brian S. Newell, James R. Neilson, Tadaaki Ikoma, Masaki Azuma, Takafumi Yamamoto. CrystlEngComm. 2022. 24 (30) 5428-5434. [doi]

(5) "Correlating Broadband Photoluminescence with Structural Dynamics in Layered Hybrid Halide Perovskites." Alexandra A. Koegel, Eve M. Mozur, Iain W.H. Oswald, Niina H. Jalarvo, Timothy R. Prisk, Madhusudan Tyagi, James R. Neilson. Journal of the American Chemical Society. 2022.  144 (3) 1313–1322 . [doi] 

(4) "Structure and optical properties of layered perovskite (MA)2PbI2-xBrx (SCN)2 (0 ≤ x < 1.6)." Takafumi Yamamoto, Iain W. H. Oswald, Christopher Savory, Takuya Ohmi, Alexandra A. Koegel, David O. Scanlon, Hiroshi Kageyama, and James R. Neilson Journal of Inorganic Chemistry 2020 53 (23) 17379-17384. [doi]

(3) “General Synthesis Principles for Ruddlesden-Popper Hybrid Perovskite Halides from a Dynamic Equilibrium.” Iain W.H. Oswald, Alexandra A. Koegel, and James R. Neilson Chemistry of Materials 2018 30 (23) 8606-8614 . [doi]

(2) “Low-Temperature Atomic Layer Deposition of CuSbS2 for Thin-Film Photovoltaics.” Shannon C. Riha, Alexandra A. Koegel, Jonathan D. Emery, Michael J. Pellin, and Alex B. F. Martinson ACS Applied Materials & Interfaces 2017 9 (5) 4667-4673. [doi]

(1) “Atomic Layer Deposition of MnS: Phase Control and Electrochemical Applications.” Shannon C. Riha, Alexandra A. Koegel, Xiangbo Meng, In Soo Kim, Yanqiang Cao, Michael J. Pellin, Jeffrey W. Elam, and Alex B. F. Martinson ACS Applied Materials & Interfaces 2016 8 (4) 2774-2780. [doi]

Select Presentations

(7) Correlating Broadband Photoluminescence and Structural Dynamics in Layered Hybrid Halide Perovskites, NanoGE, July 2022, Virtual. Invited Talk.

(6) Correlating Broadband Photoluminescence and Structural Dynamics in Layered Hybrid Halide Perovskites, GRC, June 2022, Ventura, CA. Poster.

(5)  Correlating Broadband Emission and Structural Dynamics in Two-Dimensional Perovskites, ACS Fall, Aug 2021, Fort Collins, CO. Virtual Talk. 

(4) Correlating Broadband Emission and Structural Dynamics in Two-Dimensional Perovskites, ORNL Joint Nanoscience and Neutron Scattering User Meeting, Aug 2021, Fort Collins, CO. Virtual Talk. Awarded Best Student Presentation

(3) Correlating Broadband Emission and Structural Dynamics in Two-Dimensional Perovskites, Graduate Student Showcase, Nov 2020, Fort Collins, CO. Poster. Awarded Outstanding Scholar Award

(2) Correlating Structural Dynamics and Broadband Emission in Two-Dimensional Perovskites, American Conference on Neutron Scattering, (ACNS), July 2020, Fort Collins, CO. Virtual Talk.

(1) Atomic Layer Deposition of Manganese Sulfide Thin Films for Applications in Energy Conversion and Storage, College of Letters and Science Undergraduate Research Symposium, May 2016, Stevens Point, WI. Talk.