Flux Mediated Synthesis of Cu(I)-Oxide Semiconductors for Clean Energy Application

第一部分非技术概述许多与技术相关的领域需要日益复杂的材料，这对材料的制备和开发构成了严峻的挑战。因此，目前合成方法的局限性是广泛调整物理性质和实现潜在商业应用的主要瓶颈。该项目由NSF材料研究部的固态和材料化学计划支持，旨在解决晶体半导体制备过程中的固有挑战，以促进有效地捕获阳光以减少二氧化碳。这项工作的结果导致了新的半导体的合成，例如，从这些半导体中高效地生产化学燃料，对我国朝着清洁和可再生能源生产的方向发展非常重要。在可合成性极限下发现化合物的目的是为了了解新的结构特征在太阳能捕获和转换过程中对其性质和稳定性的影响，从而推动结构-性质关系的前沿。更广泛地说，制备复杂半导体的合成方法的进步有助于加快它们在电子工业中许多相关应用的技术开发。在这些研究活动中提供本科生和研究生的专业培训，例如在国家实验室采用先进的定性技术，重点是从代表性不足的群体中招收学生。教育工作包括开发本科实验室模块以及在北卡罗来纳州立大学举办高级材料表征专业培训讲习班。第二部分技术概述通过开发合成方法来针对热力学不稳定或亚稳态的新成分和结构，可以增强获得具有技术有用特性的结晶固体的能力。发现导致其动力学稳定的潜在因素，包括那些尚未通过计算预测的化合物，是该研究项目的一个中心目标。该项目的研究计划得到美国国家科学基金会材料研究部固态和材料化学计划的支持，特别关注亚稳态、含铜(I)的半导体的研究，这些半导体在吸收太阳能和催化还原二氧化碳表面作为p型半导体具有很好的应用前景。合成方面的目标是通过使用助熔剂介导的反应条件解锁相对较低的温度路径来提高晶体结构的可及范围和最佳的光电化学性能。X射线和中子散射的结构表征被用来帮助回答有关机械合成转换和由此产生的动力学稳定性的关键问题。通过光电化学性能测量，深入探讨了优化其晶体结构和化学组成以实现在阳光下二氧化碳的有效还原的基本见解。通过密度泛函理论的协同计算，建立了它们的热力学不稳定性和电子结构之间的关键关系。教育举措包括对参与该项目的学生进行专业培训，一个新的本科固态化学实验室模块，以及使用Rietveld方法进行材料表征的年度研讨会。该奖项反映了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。

Part 1. Non-Technical Summary Many technologically relevant fields require increasingly complex materials that pose severe challenges in their preparation and development. The limitations of current synthetic approaches thus represent a major bottleneck to the extensive tuning of physical properties and for the realization of potential commercial applications. This project, supported by the Solid State and Materials Chemistry program in NSF's Division of Materials Research, addresses the challenges inherent to the preparation of crystalline semiconductors for facilitating the efficient capture of sunlight for the reduction of carbon dioxide. Results from this work leading to the synthesis of new semiconductors, and, for example, the efficient production of chemical fuels from them, are important to our nation's progress toward clean and renewable energy production. The discovery of compounds occurring at the limits of synthesizability is aimed at understanding the impacts of new structural features on their properties and stability during the capture and conversion of solar energy, and thus pushing the frontiers of structure-property relationships. More broadly, the advancement of synthetic approaches to prepare complex semiconductors helps to accelerate their technological development for many related applications in the electronics industry. The professional training of undergraduate and graduate students is provided within these research activities, such as advanced characterization techniques at national laboratories, with a focus on the recruitment of students from underrepresented groups. Educational efforts include the development of an undergraduate laboratory module as well as a professional training workshop at North Carolina State University in advanced materials characterization.Part 2. Technical SummaryAdvancing capabilities to attain crystalline solids with technologically useful properties can be bolstered by the development of synthetic approaches to target new compositions and structures that are thermodynamically unstable, or metastable. The discovery of the underlying factors leading to their kinetic stabilization, including for those compounds not yet predicted computationally, represents a central objective of the research project. Research plans for this project, which is supported by the Solid State and Materials Chemistry program in NSF's Division of Materials Research, specifically focus on the investigation of metastable, Cu(I)-containing semiconductors that have promising applications as p-type semiconductors for the absorption of solar energy and the catalytic reduction of carbon dioxide at their surfaces. Synthetic aspects are aimed at advancing the accessible range of crystalline structures and optimal photoelectrochemical properties through the unlocking of relatively low temperature pathways using flux-mediated reaction conditions. Structural characterization by X-ray and neutron scattering is used to help answer key questions regarding the mechanistic synthetic transformations and the resulting kinetic stability. Fundamental insights into the optimal tuning of their crystalline structures and chemical compositions to achieve the efficient reduction of carbon dioxide under sunlight are probed in depth by photoelectrochemical property measurements. The key relationships to their thermodynamic instability and electronic structures are also established with synergistic computational efforts using density functional theory. Educational initiatives include professional training for students involved on this project, a new undergraduate laboratory module in solid-state chemistry, and an annual workshop in materials characterization using Rietveld methods.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.