This RUI award supports computational research to design and understand "perovskite" compounds, a technologically important class of materials with the ability to absorb and harness the energy in sunlight. Perovskite compounds have the general formula ABX3, meaning they consist of three chemical elements in a 1:1:3 ratio. In the past decade, some of these compounds have shown promise in photovoltaic solar cells, meaning they can convert sunlight directly to electricity. Other perovskites are solar photocatalysts, meaning they can use sunlight to drive chemical reactions that generate fuel. A unique property of perovskites is that their structure can be changed in many subtle ways -- substituted with different elements, pulled and twisted, layered and decorated -- to optimize their ability to convert sunlight. With all of this freedom to modify perovskites, computers are valuable tools in predicting which of these materials will behave in desired ways. In this research, the principal investigator (PI), undergraduate, and master's-level students will use computers to predict how and understand why substitutions and movements of atoms affect the ability of perovskites to absorb and convert sunlight. In addition, the research group will develop a new computational method, faster than traditional methods, to quickly and roughly search the huge variety of perovskite materials for properties of interest.
The award also supports the PI's mentoring and teaching activities and curriculum development at Western Washington University, a primarily undergraduate institution. The award will enable the training and mentoring of a diverse group of undergraduate and master's students along with opportunities for the PI and students to present their work at regional and national research conferences. In recent years, the PI has worked to "flip" his undergraduate physical chemistry courses, designing in-class problem solving and computer simulation activities to engage students in more active ways. There is evidence in the education literature that this approach leads to a variety of positive learning outcomes (especially among lower-performing students) and promotes equity and inclusion by engaging students with a wide spectrum of different learning styles. In the coming years, the PI will refine and further develop these curricular materials for physical chemistry and develop similar student-centered training materials relevant to his group's research areas. These materials will help students learn about fields such as computational and solid-state chemistry, which are rarely covered in the undergraduate curriculum.
This RUI award supports computational research to design and understand perovskite compounds for solar energy conversion. In the past decade, halide perovskite solar cells have emerged as a promising and rapidly developing technology. So too have oxide perovskites been explored for solar photocatalysis. Along with advances in synthesis and device engineering, there have been density functional theory (DFT)-based studies of various aspects of the structure and properties of these materials. However, due in large part to the structural complexity of experimentally relevant perovskite superstructures and nanostructures, cases in which theory and computation have truly been on the leading predictive edge of this field have been limited. In order to advance fundamental understanding of structure/property relationships and guide experimentalists in the search for new materials, the PI, undergraduate, and master's-level students will study three research areas in the computational elucidation and design of halide and oxide perovskites. These projects will use electronic structure calculations to: 1) tune electronic properties using strain and its couplings to composition and structural distortion; 2) identify novel, energetically stable classes of perovskite superstructures with desired properties; 3) develop, test, and deploy a new semi-empirical approach (based on the extended Hueckel method) to the rapid high-throughput screening of complex perovskite superstructures and nanostructures. These projects will advance the state of the field in terms of fundamental understanding, discovery and tuning of new materials, and method development.
The award also supports the PI's mentoring and teaching activities and curriculum development at Western Washington University, a primarily undergraduate institution. The award will enable the training and mentoring of a diverse group of undergraduate students (with nine summer research stipends over three years) and a master's student, and opportunities for the PI and students to present their work at regional and national research conferences. Students will learn about renewable energy and key areas of chemistry (computational and solid state) that are rarely seen in the undergraduate curriculum, and will gain computational skills (Linux and programming) that are increasingly valued in the modern workforce. In parallel with these research efforts, the PI will develop and assess synergistic educational materials for students, in the form of standalone computer simulation lessons in key topics of solid state chemistry (e.g., crystal structure and symmetry, X-ray diffraction, and electronic band structure and reciprocal space). These lessons are an outgrowth of the suite of computer simulation lessons that the PI has developed and used in student-centered activities in undergraduate physical chemistry courses.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
