conference paper published yes Seungho Lee author BB243B88-D767-11E9-B658-BC13E66974250000-0002-6962-8598 Daniel Balazs author 302BADF6-85FC-11EA-9E3B-B9493DDC885E0000-0001-7597-043X Sharona Horta author 03a7e858-01b1-11ec-8b71-99ae6c4a05bc Aiswarya Rayaroth Puthiyaveettil author 8aceb01b-8972-11ed-ae7b-d5fe53775add Maria Ibáñez author 43C61214-F248-11E8-B48F-1D18A9856A870000-0001-5013-2843 MaIb department LifeSc department MATSUS: Materials for Sustainable Development Conference HighTE: The Werner Siemens Laboratory for the High Throughput Discovery of Semiconductors for Waste Heat Recovery project Supercrystals represent three-dimensional orderings of colloidal nanocrystals (NCs), showcasing collective properties in photonics, phononics, and electronics applications.1,2 Recent studies have shown that such assemblies are directly produced during nanocrystal reactions.3–6 However, a fundamental understanding of in situ formed supercrystals that withstand typical NC purification processes remains underexplored, which is important for further use. Herein, we report the reaction precursor-mediated formation of stable PbTe supercrystals. Rationalizing the formation of these assemblies through small-angle x-ray scattering (SAXS) measurements, we unveil their formation mechanism. Our findings reveal that the supercrystal formation occurs in the presence of an excess of lead oleates in the crude solution. It should be noted that the formed supercrystals can be stabilized under specific conditions determined by the lead oleate cluster concentration, content of trioctylphosphine telluride (TOP-Te), NC size and the need of an annealing step at mild conditions. Furthermore, this approach allows for the continuous growth of a secondary phase within the supercrystal; for example in the case of PbTe supercrystals, a PbS shell can be grown on each PbTe NC constituent, resulting in core-shell PbTe-PbS supercrystals. Our work elucidates that reaction precursors play an important role in in situ SC formation and stabilization, implying the possibility of applying this knowledge to other NC reactions. Fundació de la comunitat valenciana SCITO2025Sevilla, Spain eng 10.29363/nanoge.matsusspring.2025.173 S. Lee, D. Balazs, S. Horta, A. Rayaroth Puthiyaveettil, and M. Ibáñez, “Reaction precursor-mediated formation of stable supercrystals in colloidal nanocrystal synthesis: PbTe case,” in <i>Proceedings of the MATSUS Spring 2025 Conference</i>, Sevilla, Spain, 2025. S. Lee, D. Balazs, S. Horta, A. Rayaroth Puthiyaveettil, M. Ibáñez, in:, Proceedings of the MATSUS Spring 2025 Conference, Fundació de la comunitat valenciana SCITO, 2025. Lee S, Balazs D, Horta S, Rayaroth Puthiyaveettil A, Ibáñez M. 2025. Reaction precursor-mediated formation of stable supercrystals in colloidal nanocrystal synthesis: PbTe case. Proceedings of the MATSUS Spring 2025 Conference. MATSUS: Materials for Sustainable Development Conference, 173. Lee, Seungho, Daniel Balazs, Sharona Horta, Aiswarya Rayaroth Puthiyaveettil, and Maria Ibáñez. “Reaction Precursor-Mediated Formation of Stable Supercrystals in Colloidal Nanocrystal Synthesis: PbTe Case.” In <i>Proceedings of the MATSUS Spring 2025 Conference</i>. Fundació de la comunitat valenciana SCITO, 2025. <a href="https://doi.org/10.29363/nanoge.matsusspring.2025.173">https://doi.org/10.29363/nanoge.matsusspring.2025.173</a>. Lee, Seungho, et al. “Reaction Precursor-Mediated Formation of Stable Supercrystals in Colloidal Nanocrystal Synthesis: PbTe Case.” <i>Proceedings of the MATSUS Spring 2025 Conference</i>, 173, Fundació de la comunitat valenciana SCITO, 2025, doi:<a href="https://doi.org/10.29363/nanoge.matsusspring.2025.173">10.29363/nanoge.matsusspring.2025.173</a>. Lee S, Balazs D, Horta S, Rayaroth Puthiyaveettil A, Ibáñez M. Reaction precursor-mediated formation of stable supercrystals in colloidal nanocrystal synthesis: PbTe case. In: <i>Proceedings of the MATSUS Spring 2025 Conference</i>. Fundació de la comunitat valenciana SCITO; 2025. doi:<a href="https://doi.org/10.29363/nanoge.matsusspring.2025.173">10.29363/nanoge.matsusspring.2025.173</a> Lee, S., Balazs, D., Horta, S., Rayaroth Puthiyaveettil, A., &#38; Ibáñez, M. (2025). Reaction precursor-mediated formation of stable supercrystals in colloidal nanocrystal synthesis: PbTe case. In <i>Proceedings of the MATSUS Spring 2025 Conference</i>. Sevilla, Spain: Fundació de la comunitat valenciana SCITO. <a href="https://doi.org/10.29363/nanoge.matsusspring.2025.173">https://doi.org/10.29363/nanoge.matsusspring.2025.173</a> 200552025-07-21T08:33:20Z2026-02-19T09:25:57Z