Chemical Pathways for Controlling Polymorphism in Nanoscale Metal Chalcogenides

固态和材料化学（SSMC）计划的这一奖项支持宾夕法尼亚州立大学的Raymond Schaak教授的工作，以确定和理解导致过渡金属硫化物和硒化物的纳米颗粒非平衡相形成的化学因素，包括ZnS，ZnSe，以及Co，Ni和Mn的几种硫化物和硒化物。 目标材料表现出各种有趣和有用的电子，磁性和光学特性，其晶体结构直接影响其性能。 这项研究建立在新兴的能力，合成非平衡相使用化学路线，形成纳米颗粒固体在溶液中从可溶性前体。 这些发现通常是偶然的，涉及大量的变量和复杂的原位化学。 在该项目中，Schaak教授的团队研究了这些新固体形成的反应途径，以揭示重要的见解，这些见解可以帮助建立一个预测框架，用于根据基本化学原理选择性地针对所需的非平衡相。扩展固体采用的晶体结构在定义其性质方面发挥着关键作用。 同时，用于合成固体的技术和条件可以帮助影响它形成的晶体结构。 该项目旨在识别和理解选择性地导致一种晶体结构而不是其他结构形成的化学因素，在一个可以访问多种结构的系统中。 这些见解将帮助研究人员更可预测地合成具有目标特性的所需材料。 该项目提供多学科的培训，以研究生和本科生的多样化群体。 重点是通过专门设计的本科研究项目，将本科研究人员团队直接融入项目的技术目标。

This award by the Solid State and Materials Chemistry (SSMC) program supports work by Professor Raymond Schaak at the Pennsylvania State University to identify and understand the chemical factors that lead to the formation of nanoparticulate non-equilibrium phases of transition metal sulfides and selenides, including ZnS, ZnSe, and several sulfides and selenides of Co, Ni, and Mn. The targeted materials exhibit a variety of interesting and useful electronic, magnetic, and optical properties, and their crystal structures directly impact their properties. This research builds on emerging capabilities for synthesizing non-equilibrium phases using chemical routes that form nanoparticulate solids in solution from soluble precursors. Such discoveries are usually serendipitous, involving a large number of variables and complex in-situ chemistry. In this project, Prof. Schaak's group investigates the reaction pathways by which these new solids form to reveal important insights that can help lead to a predictive framework for selectively targeting desired non-equilibrium phases based on fundamental chemical principles.The crystal structure that an extended solid adopts plays a key role in defining its properties. At the same time, the techniques and conditions used to synthesize a solid can help to influence the crystal structure that it forms. This project seeks to identify and understand the chemical factors that selectively lead to the formation of one crystal structure instead of others in a system where multiple structures may be accessible. These insights will help researchers to more predictably synthesize desired materials with targeted properties. This project provides multi-disciplinary training to a diverse group of graduate and undergraduate students. Emphasis is placed on integrating teams of undergraduate researchers directly into the technical goals of the project through specially designed undergraduate research projects.