Manipulation of Precursor Coordination and Reactivity to Enable Phase-tunability in Colloidally Synthesized Transition Metal Dichalcogenide Nanocrystals

在化学系大分子、超分子和纳米化学(MSN)计划的支持下，加州大学圣地亚哥分校的Alina Schimpf教授正在开发合成过渡金属二盐基化物(TMD)的新策略。这类材料具有广泛的潜在应用，包括先进电子学、化学催化和量子信息科学。TMD的性质不仅取决于它们的原子组成，而且还取决于特定的原子排列(晶相)。要发掘它们的技术潜力，以纯形式产生感兴趣的阶段的能力至关重要。与传统的固相合成不同，Schimpf教授和她的团队使用溶液化学直接合成同相的TMD。通过有针对性地努力获得的关于这类TMDs的信息广泛适用于其他TMDs和无机材料的合成，并为其提供信息。辛普夫教授还利用这些研究作为平台，通过与西班牙裔服务机构圣地亚哥梅萨学院的合作，为社区大学的学生提供研究经验。教育推广活动为学生提供了与博士化学家合作并学习高级化学研究的机会。过渡金属二卤代化合物(TMD)在电子学、光电子学、催化和量子自旋信息科学等领域具有潜在的应用前景，有望在新兴技术中发挥重要作用。这些材料的不同应用源于不同的晶相，产生了独特而多样的电子和光物理性质。Schimpf教授的研究利用分子前体的配位化学和反应性，利用胶体化学方法获得了组成为ME2(M=Mo，W；E=S，Se)的VI族TMD的相可调合成。这项研究探索了控制合成和维持亚稳态相能力的化学原理。主要目标是发展对纳米晶体形成的化学的微观理解，以便合理地合成具有所需特性的TMD纳米晶体。从这项研究中获得的见解正被用于磨练设计原则，并反复增加结构设计的复杂性，从而能够获得更高质量和物相纯的无机材料。这些研究最终可能使新的战略能够接触到广泛的TMD的新的或奇异的阶段。Schimpf教授还与圣地亚哥梅萨学院的社区大学生合作，让他们参与设计和进行WS2纳米晶体合成的研究。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program in the Division of Chemistry, Professor Alina Schimpf at University of California, San Diego is developing new strategies for the synthesis of transition metal dichalcogenides (TMDs). This class of materials has a wide array of potential applications including advanced electronics, chemical catalysis, and quantum information science. The properties of a TMD depend not only on their atomic composition, but also on the specific atomic arrangement (the crystal phase). To uncover their technological potential, the ability to generate phases of interest in pure form is critical. Unlike traditional solid-state syntheses, Professor Schimpf and her group use solution chemistry to directly synthesize TMDs of the same phase. The information garnered through targeted efforts on this type of TMDs is broadly applicable to and informs the synthesis of other TMDs and inorganic materials. Professor Schimpf is also using these studies as a platform to provide research experiences for community college students by partnering with San Diego Mesa College, an Hispanic Serving Institution. The educational outreach activity provides opportunities for students to work alongside PhD chemists and learn about advanced chemistry research. Transition metal dichalcogenides (TMDs) are poised to play an important role in emerging technologies, with potential uses in electronics, optoelectronics, catalysis and quantum spin information science. The various applications of these materials are derived from different crystal phases, giving rise to unique and diverse electronic and photophysical properties. Professor Schimpf’s research uses colloidal chemistry to access phase-tunable syntheses of group-VI TMDs with composition ME2 (M = Mo, W; E = S, Se) by exploiting the coordination chemistry and reactivity of the molecular precursors. This research explores the chemical principles that govern the ability to synthesize and maintain metastable phases. The primary objective is to develop a microscopic understanding of the chemistry that governs nanocrystal formation in order to rationally synthesize TMD nanocrystals with the desired properties. The insights gained from this research are being used to hone the design principles and iteratively add complexity to the structural design, enabling access to higher-quality and phase-pure inorganic materials. These studies may ultimately enable new strategies to access new or exotic phases of a wide range of TMDs. Professor Schimpf is also working with community college students from San Diego Mesa College, a local Hispanic Serving Institution, by engaging them in the research of designing and conducting syntheses of WS2 nanocrystals.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.