LEAPS-MPS: Combinatorial chemical synthesis of resilient metal chalcogenides with reactive printing

NON-TECHNICAL SUMMARY Solid-solution metal chalcogenides are emerging semiconductors consisting of metals and chalcogens (e.g., sulfur, selenium, tellurium). These materials offer considerable potential for energy conversion and data storage applications due to their tunable electronic properties; however, their thermal stability remains limited by elemental sublimation and phase segregation after thermal exposure. Although past studies have shown that alloying and doping can mitigate thermal degradation, thermal stability varies with chemical compositions, highlighting the need to understand degradation pathways under complex compositions. This LEAPS-MPS project will use a reactive printing technique to accelerate the design, understanding, and discovery of new metal chalcogenides with improved thermal stability. To achieve this goal, the PI will develop a printing-based high-throughput synthesis technique for solid-solution chalcogenides, facilitating rapid screening and detailed study of their structure-property relationships. This method allows for the synthesis and manipulation of complex chalcogenide systems without the high-energy processes that limit traditional synthesis techniques, facilitating the understanding of mesoscale and interface-related phenomena. With an emphasis on the local and surrounding rural schools in West Texas, this project will involve actively recruiting undergraduate researchers from these groups and incorporating research results into educational outreach programs. Through career-focused outreach programs, the project will provide rural K-12 minority students with opportunities for hands-on research experience and prepare them for STEM careers. TECHNICAL SUMMARY While solid-solution metal chalcogenides have attracted significant attention in energy, sensing, and computing, the poor thermal stability of chalcogenide materials limits their ability to operate in extreme environments or dynamic climates. To overcome this limitation, this LEAPS-MPS project seeks to understand and control the critical factors in the thermal degradation pathways of printed chalcogenides to develop effective strategies for improving the thermal stability of metal chalcogenide materials. To achieve this goal, the PI will develop a high-throughput combinatorial reactive printing technique that synthesizes a gradient of chalcogenides from the chemical reaction of starting precursors (e.g., nanoparticles, dopants, and ligands), which will form compositionally varying alloys during the post-print atmosphere-controlled sintering stage. These compositionally complex samples will undergo extreme thermal flux, where the compositional and structural changes at different film locations will be studied to understand the role of elemental modulation in thermal stability as a function of temperature and time. A complementary machine-learning study of the stability data will be performed to identify the key factors limiting the chemical stability of printed chalcogenides under extreme conditions. By studying the fundamental relationship between the composition, processing conditions, and stability of the samples, the project will develop a deep understanding of what, and more importantly, why the optimal composition and doping factors will advance the stability of the metal chalcogenides. 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.