Accelerating Synthesizability of Mixed Anion Materials

About This Grant

Non-technical summary: This award supports research to accelerate the making of new inorganic materials, which are vital components of next-generation energy, optoelectronic, and biomedical devices. Often new materials are created through a trial-and-error approach that depends on the intuition of the researcher, but this is inefficient and wasteful of both materials and time. With support from the Solid State and Materials Chemistry program and the Ceramics program, both in the Division of Materials Research, the researchers predict how to make new inorganic materials using computational materials science and validate these predictions in the laboratory, setting up a feedback loop to further improve future predictions. Computational predictions rely on the understanding of material thermodynamic properties, and laboratory experiments use real time characterization to monitor how the material is made. The feedback loop is employed to make perovskite oxynitrides, which are inorganic materials with highly tunable properties. The impact of the starting materials, also known as precursors, from which perovskite oxynitride products form is being investigated, and formation pathway maps to perovskite oxynitrides from varied precursors and reaction conditions are being created. Through this project, the team of researchers bridges the gap between computer-aided materials design and practical synthesis in the laboratory, which benefits society by accelerating the creation of inorganic materials with useful functional properties. This award also supports activities to expose a broad age range of students to inorganic materials science through low-cost, hands-on science kits (grades K-12) and focused research experiences for undergraduate students at Drexel University. Technical summary: With support from the Solid State and Materials Chemistry program and the Ceramics program, both in the Division of Materials Research, this award supports research focused on clarifying the synthesizability of solid-state inorganic materials relevant for applications in energy generation and storage, catalysis, and optoelectronic devices. The research co-leverages computation and experiment in an integrated feedback loop to accelerate inorganic material synthesis and reduce waste to scale-up. Specifically, thermodynamic modelling employing the CALculation of PHAse Diagram (CALPHAD) approach provides synthetic guideposts, while ex situ and in situ solid-state reactions unveil reaction pathways and validate and improve computational predictions. The materials of interest are mixed anion perovskite oxynitrides which possess highly tunable optical and electronic properties sensitive to the choice of cations, smaller electronegativity of nitrogen with respect to oxygen, and anion ordering. These materials have been synthesized sparingly experimentally, and many more are predicted to be stable or metastable. The central hypothesis is that informed choice of precursor and precursor reactivity can minimize the nucleation barrier for synthesis of these materials, with high reactivities and low interfacial energies favoring the formation of metastable perovskite oxynitrides. To showcase the role of precursors, reaction conditions, and kinetics on formation of these materials, multi-variable phase space diagrams that capture and map precursor to intermediate to product are being created. This award also supports educational and outreach activities that are informed by the research direction, including incorporating new inquiry-based science activities on inorganic materials synthesis into low-cost kits for K-12 students and broadening the participation of undergraduate researchers in informed materials synthesis at Drexel University. 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.