(4fx) Materials Design for Energy and Environmental Applications

My research interests lie within the broad field of colloid and interface science. The main focus has always been on the development of novel materials with unique electronic, optical, and mechanical properties. Fundamental understandings of structures, dynamics, and properties of the materials will be obtained. Meanwhile, their applications in energy storage, wearable sensors, stimuli-responsive devices, and smart windows will be pursued to address societal challenges. Ultimately, a general guideline will be formed for better designing materials to address challenges in a specific area. Scattering-based techniques are used as important tools to probe the structures and dynamics of the materials over a wide range of length scales. It facilitates the development of materials by providing valuable information on the formation mechanism, phase behavior, as well as kinetics. Colloid and interface science possess rich opportunities for the discovery of novel materials. I am enthusiastic to collaborate with other experts to promote the development of this field.

The understanding of the relationship between structure, dynamics, and property in multi-length scales is crucial in developing next-generation functional materials. This is especially true for soft materials, such as polymers and colloidal gels, due to their large design freedom and, at the same time, great challenges in forming well-controlled structures. Hierarchical structure design has widely revolutionized the fields of energy, nanotechnology, and biomedical applications with novel materials or intriguing properties. My previous research experience emphasizes the critical roles fundamental understanding play in realizing new technologies. The multi-length scale information from scattering techniques is analyzed and served as a guideline for formulating strategies to assemble materials with specific properties. Not only could desired structure be achieved, but stimuli-responsive materials with on-demand tunability of properties are also obtained.

Teaching Interests:

I am interested in teaching core chemical engineering classes, such as kinetics and thermodynamics. Besides, my specialized training is in colloid and interface science and I am also interested in teaching relevant classes. I spent two semesters teaching colloids and interfacial science laboratory and two semesters teaching unit operation laboratory. I also served as an instructor during the summer school at the NIST Center for Neutron Research (NCNR) for teaching scattering-based techniques and analysis. Aside from those, I mentored graduate and undergraduate students in the past in my research group. Currently, I am participating as a mentor to instruct an undergraduate student in the Summer Undergraduate Research Fellowship (SURF) program at the National Institute of Standards and Technology.

Despite what class I will be teaching, my goal is to help students succeed, both in the classroom and moving beyond. I believe that effective teaching exists in different styles and various forms. Being a student and a researcher throughout the years, I witnessed many ways of teaching. At the same time, as a teaching assistant myself, I also had my thoughts from a different point of view on promoting the learning experience of students. Thus, I am eager to apply what I have learned to motivate students to be life-long learners, encourage them to learn with a positive attitude, and foster independent practices, as well as interactive communications.

Successful Proposals:

Experimental proposals that have been granted beamtimes from synchrotron- and neutron-based national labs, including 10 proposals to NIST Center for Neutron Research (NCNR), 4 proposals to Argonne National Laboratory, 2 proposals to Brookhaven National Laboratory, and 1 proposal to Oak Ridge National Laboratory (ORNL).

Services:

2019~Present: Executive committee of Neutron Scattering Society of America (NSSA)

2016~Present: 40 invited reviews from scientific journals.

Postdoctoral Project:

“Porous materials under extreme conditions”

Under the supervision of Yun Liu,

1. NIST Center for Neutron Research
2. Department of Chemical & Biomolecular Engineering, University of Delaware

Ph.D. Dissertation:

“Structure Engineering of Self- and Directed-Assembled Conjugated Polymers”

Under the supervision of Lilo D. Pozzo, Chemical Engineering, University of Washington

Committee members: Christine K. Luscombe, Stuart Adler, and Lih Lin

Research Experience:

My research experience is mainly focused on interdisciplinary fields involving materials, physics, and engineering. I was trained in the field of colloid science with an emphasis on structural characterization using scattering techniques. To achieve different functions, the assembly of materials is controlled to realize specific structures. My previous research experience is focused on the assembly of polymers and colloidal particles. External electric and acoustic fields are demonstrated to guide conductive polymers to grow into aligned structures or fibers with high aspect ratios. The charge transport is thus enhanced. By carefully engineering the solvent-solvent and solvent-solute interactions, a ternary system can be designed to not only achieve desired structures but also obtain stimuli-responsive materials with on-demand tunability of properties. Recently, I discovered a novel material, solvent segregation driven gel (SeedGel), which has many intriguing properties and broad applications. It opens up many interesting research directions that have not yet been explored.

I have learned the fundamental physics behind the assembly of polymers and nanomaterials, which can be used to achieve unique functions with hierarchically engineered structures. I acquired the knowledge and invaluable experience by closely working with instrument scientists in national labs while conducting experiments. At the same time, the purpose of engineering structures is to obtain unique functions. The projects that I worked on always involved collaborations and closely related fundamental science to applications. Examples include photovoltaics, transistors, sensors, optoelectronics, batteries, and biomimetic materials.

Selected Publications:

Yuyin Xi et al., “Controlling Bicontinuous Structures through Solvent Segregation Driven Gel”, Langmuir, 37, 6, 2170 (2021).

Yuyin Xi et al., “Tunable Thermo-reversible Bicontinuous Nanoparticle Gel Driven by the Binary Solvent Segregation”, Nature Communications, 12, 910 (2021). (Highlighted by NIST, Editors’ Highlight by Nature Communications)

Yuyin Xi, Caitlyn M. Wolf, Lilo D. Pozzo, “Self-assembly of Donor-acceptor Conjugated Polymers Induced by Miscible Poor Solvents”, Soft Matter, 15, 1799, (2019).

Yuyin Xi, David S. Li, Greg M Newbloom, Wesley K Tatum, Matthew O’Donnell, Christine K. Luscombe, Lilo D Pozzo, “Sonocrystallization of Conjugated Polymers with Ultrasound Fields” Soft Matter, 14, 4963, (2018).

Yuyin Xi, David S. Li, Yi-Ting Lee, and Lilo D. Pozzo, “In-Situ Ultrasound sample environment for small angle scattering studies” 2018 NCNR Highlight (2018).

Yuyin Xi, Lilo D. Pozzo, “Electric Field Directed Formation of Aligned Conjugated Polymer Fibers” Soft Matter, 13, 21, 3894, (2017).

Yuyin Xi, Yueh-Ling Hsieh, Ya-Hsi Hwang, Shun Li, Fan Ren, Stephen J Pearton, Erin Patrick, Mark E Law, Gwangseok Yang, Hong-Yeol Kim, Jihyun Kim, Albert G Baca, Andrew A Allerman, Carlos A Sanchez “Effect of 5 MeV proton radiation on DC performance and reliability of circular-shaped AlGaN/GaN high electron mobility transistors” Journal of Vacuum Science & Technology B 32, 012201(2014).

Yuyin Xi, Lu Liu, Fan Ren, Stephen J Pearton, Jihyun Kim, Amir Dabiran, Peter P Chow, “Methane detection using Pt-gated AlGaN/GaN high electron mobility transistor based Schottky diodes” Journal of Vacuum Science & Technology B 31, 032203(2013).

Yuyin Xi, Lu Liu, Ya-Hsi Hwang, Oluwadamilola Phillips, Fan Ren, Stephen J Pearton, Jihyun Kim, Chien-Hsing Hsu, Chien-Fong Lo, Jerry Wayne Johnson, “Study of hydrogen detection response time at room temperature with Pt-gated diodes fabricated on AlGaN/GaN hetero-structure” Journal of Vacuum Science & Technology B 31, 032202(2013).

Jiangsheng Yu, Yuyin Xi, Chu-Chen Chueh, Jing-Qi Xu, Hongliang Zhong, Francis Lin, Sae Byeok Jo, Lilo D Pozzo, Weihua Tang, Alex K-Y Jen, “Boosting Performance of Inverted Organic Solar Cells by Using a Planar Coronene based Electron-transporting Layer” Nano Energy, 39, 454, (2017).

Patents:

1. Pending U.S. Patent: Method to Thermo-Reversibly Control Light and Heat Flow with Bicontinuous Micro-Domain