CAREER: Exploring Luminescence in Low-Dimensional Halides

发光材料由于其在现有技术的灯、显示器（例如，电视、显示器）和医疗扫描仪，以及它们在光学设备和生物医学领域的潜力。发光材料的重要性已得到全球的认可，被联合国指定为2015年庆祝国际光和光基技术年。为了进一步说明这一点，估计节能固态照明（例如，LED）可以在2035年将照明能源使用量减少75%。在这个由材料研究部门的固态和材料化学计划以及刺激竞争研究的既定计划（EPSCoR）共同支持的职业奖中，Bayram Saparov教授和他的团队旨在开发一种新型的基于廉价金属卤化物的经济实惠，易于制备，地球丰富和坚固的发光材料。该项目对理解金属卤化物的发光特性和原子结构之间的联系具有潜在的变革性影响。反过来，这将使我们能够控制和操纵卤化物的材料化学，以制备具有全范围颜色可调性的定制设计发光材料。除了节能固态照明技术的全新途径外，该项目还将提供一个绝佳的平台，通过我们的高中生研究经验（REHSS）计划，促进材料化学研究并在俄克拉荷马州培养多元化、有竞争力的科学、技术、工程和数学（STEM）劳动力。REHSS计划将为俄克拉荷马州的高中生提供真实的两个月的研究经验;参与者包括主要为少数民族社区服务的偏远农村学校。最近报道，全无机卤化铜由于其低成本、地球上丰富的化学组成、溶液可加工性和创纪录的高发光效率而成为光学应用的优异候选物。这些卤化铜具有独特的能带结构，其中铜（I）轨道支配带隙周围的状态，这导致其光致发光性质的可调谐性差。在材料研究部门的固态和材料化学计划以及刺激竞争研究的既定计划（EPSCoR）的共同支持下，Bayram Saparov教授及其团队将通过对拟议系统中化学组成-结构-性能关系的基本理解，开发新的策略来控制铜和银卤化物的结构和发光性能。 所提出的卤化物的低维晶体结构表现出窄的离散能带、强电荷局域化和高激子结合能的特性，并且应该使它们能够作为高效发光体。这些努力将提供一个更广泛的，协同的研究和教育计划，旨在促进材料化学研究和开发一个多样化的，有竞争力的干劳动力在俄克拉荷马州的核心构件。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

NON-TECHNICAL SUMMARY Luminescent materials continue to play a major role in modern society owing to their applications in the state-of-the-art lamps, displays (e.g., TVs, monitors) and medical scanners, and to their potential in the fields of optical devices and biomedicine. The importance of luminescent materials has been recognized globally, designated by the United Nations, 2015 was celebrated as the International Year of Light and Light-based Technologies. To further illustrate this, it is estimated that energy-efficient solid-state lighting (e.g., LEDs) could reduce lighting energy use by 75% in 2035. In this CAREER award, jointly supported by the Solid State and Materials Chemistry program in the Division of Materials Research and the Established Program to Stimulate Competitive Research (EPSCoR), Prof. Bayram Saparov and his group aim to develop a new type of affordable, easy-to-prepare, earth-abundant and robust luminescent materials based on inexpensive metal halides. The project has a potential transformative impact on understanding of the links between the light emission properties and atomic structures of metal halides. This, in turn, will allow us to control and manipulate the materials chemistry of halides to prepare custom design light-emitting materials with full range color-tunability. In addition to brand new avenues for energy-saving solid-state lighting technologies, this project will also provide an excellent platform for promoting materials chemistry research and developing a diverse, competitive Science, Technology, Engineering, and Mathematics (STEM) workforce in Oklahoma through our Research Experience for High School Students (REHSS) program. The REHSS program will provide a real two-month research experience for Oklahoma high school students; participants include remote rural schools that are primarily serving minority communities. TECHNICAL SUMMARYAll-inorganic copper halides have recently been reported as excellent candidates for optical applications owing to their low cost, earth-abundant chemical compositions, solution processability and record high luminescence efficiencies. These copper halides have unique band structures in which copper(I) orbitals dominate the states around the bandgap, which result in poor tunability of their photoluminescence properties. With this CAREER award, jointly supported by the Solid State and Materials Chemistry program in the Division of Materials Research and the Established Program to Stimulate Competitive Research (EPSCoR), Prof. Bayram Saparov and his group will develop new strategies to control the structures and light emission properties of copper and silver halides through a fundamental understanding of chemical composition-structure-property relationships in the proposed systems. Low-dimensional crystal structures of the proposed halides exhibit narrow discrete energy bands, strong charge localization and high exciton binding energies, characteristics and should enable their performance as highly efficient light emitters. These efforts will provide a core building block of a broader, synergistic research and education program aimed at promoting materials chemistry research and developing a diverse, competitive STEM workforce in Oklahoma.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.