Solving the Colloidal and Photophysical Instability Problems of Perovskite Quantum Dots via Surface Ligand Engineering

在化学学部的大分子、超分子和纳米化学（MSN）项目和材料研究部的固态和材料化学（SSMC）项目的支持下，佛罗里达州立大学的Mattoussi教授和Ma教授正在开发提高钙钛矿胶体纳米晶体长期稳定性的策略。胶体钙钛矿纳米晶体是一类具有独特物理和光谱特性的半导体纳米晶体。这些特性对于各种技术应用非常有用，例如能量收集和发光器件（led）。然而，它们有限的胶体和结构稳定性阻碍了对其的深入理解，并抑制了这些材料进一步集成到电子设备中。Mattoussi教授和Ma教授探索的策略包括设计一套新的金属配位聚合物，这些聚合物可以在广泛的条件下赋予这些材料长期稳定性，保持纳米晶体的完整性，并增强其光学和电子特性，从而使材料更接近工业应用。该研究提供了一个例子，化学，材料科学和工程相结合，以解决重要的基本问题和推进新技术。该项目还为研究生和本科生在化学合成、工程和发光器件的高级分析表征等方面提供了良好的培训。此外，Mattoussi和Ma教授正在与佛罗里达科学、技术、工程和数学研究中心（FCR-STEM）合作，制作并向教师和学生传播K-12科学视频。这个由美国国家科学基金会支持的项目利用界面化学方法解决了影响钙钛矿纳米晶体的一些突出问题，例如胶体和结构稳定性差。胶体钙钛矿纳米晶体的核心由全无机或有机/无机杂化材料制成，并表现出几种独特的光物理性质。它们具有在各种技术应用中使用的潜力。其中包括在显示技术和光伏电池中的应用。阻碍这些材料深入表征和在工业上进一步应用的一个主要技术障碍是它们相当有限的稳定性。为了解决这个问题，Mattoussi和Ma团队正在设计和优化一组配位聚合物，这些聚合物可以提供两性离子或阳离子/阴离子锚定。配体的设计在控制配位基序的数量、结构和性质以及增溶块方面提供了灵活性，从而提供了可以与纳米晶体表面紧密相互作用的聚合物。这种涂层可以在广泛的条件下赋予这些材料空间稳定性，保持纳米晶体的完整性，并有可能提高它们的光学和电子性能。目前的项目本质上是跨学科的，因此，它提供了在材料化学、光谱学和设备工程等几个领域训练学生的机会。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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 and the Solid State and Materials Chemistry (SSMC) Program in the Division of Materials Research, Professors Mattoussi and Ma at Florida State University are developing strategies to enhance the long-term stability of colloidal perovskite nanocrystals. Colloidal perovskite nanocrystals are a class of semiconductor nanocrystals that exhibit several unique physical and spectroscopic properties. These properties can be extremely useful for various technological applications, such as energy harvesting and light-emitting devices (LEDs). However, their limited colloidal and structural stabilities have prevented in depth understanding and inhibited further integration of these materials into electronic devices. The strategies explored by Professors Mattoussi and Ma involve the design of a new set of metal-coordinating polymers that may impart long-term stability to these materials over a wide range of conditions, preserve the nanocrystal integrity, and enhance their optical and electronic properties, thereby bringing the materials closer to use in industrial applications. The research provides an example where chemistry, materials science,and engineering are combined to address important fundamental problems and to advance new technologies. The project also provides a good training for graduate and undergraduate students in aspects ranging from chemical synthesis, engineering, and advanced analytical characterization of light-emitting devices. In addition, Professors Mattoussi and Ma are collaborating with the Florida Center for Research in Science, Technology, Engineering, and Mathematics (FCR-STEM) to create and disseminate K-12 science videos to teachers and students.This NSF-supported project addresses some of the salient problems affecting perovskite nanocrystals, such as poor colloidal and structural stability, using interfacial chemistry approaches. Colloidal perovskite nanocrystals have cores made of either all–inorganic or organic/inorganic hybrid materials and exhibit several unique photophysical properties. They have potential for use in a variety of technological applications. These include use in display technology and photovoltaic cells. One major technical hurdle that has inhibited in-depth characterization and further application of these materials in industry has been their rather very limited stability. To address this issue, the Mattoussi and Ma groups are designing and optimizing a set of coordinating polymers that present either zwitterion or cation/anion anchors. The ligand design offers flexibility in controlling the number, structure and properties of the coordinating motifs as well as the solubilizing blocks, providing polymers that can tightly interact with the nanocrystal surfaces. Such coatings can impart steric stability to these materials over a wide range of conditions, preserve the nanocrystal integrity and potentially enhance their optical and electronic properties. The present project is interdisciplinary in nature, and as such, it provides opportunities for training students in several areas of materials chemistry, spectroscopy, and device engineering.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.