Continuous Production of Semiconductor and Hybrid Nanocrystals by Spray Pyrolysis

主要研究者：Mark Swihart机构：纽约州立大学布法罗分校提案编号：0652042标题：目标：通过喷雾热解连续生产半导体和混合纳米晶体PI计划研究喷雾热解方法生产半导体和多组分纳米晶体的可能性和局限性，这些纳米晶体具有足够小的尺寸，以显示尺寸和形状依赖的光学和电子特性。 基于这些尺寸和形状可调的特性，从生物成像到太阳能电池和发光二极管，一系列潜在的应用都是可能的。 开发生产这些材料的可重复、可控和可扩展的连续工艺对于实现这些应用至关重要。 在喷雾热解中，其变体将在本文中开发和探索，液体前体溶液被喷雾为细滴的雾（气溶胶），其被加热以诱导固体颗粒的形成。 他将研究两种喷雾热解方法：（1）完全蒸发/气相成核模式，其中气溶胶用作将高浓度的中等挥发性前体输送到气相中的手段，以及（2）不完全蒸发模式，每个前体液滴形成多个产物颗粒，其中每个气溶胶液滴用作毫微微升规模的液相反应器，由于其尺寸小，可以非常迅速地加热或冷却，并且在浓度和温度上保持均匀。 第一种方法通过允许使用比其他方法可能的低挥发性和低稳定性的前体来扩展其他气相合成方法的能力。 第二种方法使人们能够将强大的溶液相方法扩展到更高的温度和更短的反应时间，而不是在溶液中的常规间歇工艺。 PI在各向异性和混合半导体纳米晶体的溶液相合成以及其他材料的喷雾热解合成方面的最新进展，表明了结合和扩展这些方法的自然研究方向。 这将推进纳米粒子合成能力和我们对纳米粒子成核、生长和形状演变动力学的理解。 该项目的目标是：（1）确定在何种程度上可以通过完全蒸发和气相反应的前体作为气溶胶提供的气相中应用的生产半导体纳米晶体和混合纳米晶体的溶液相方法。(2)演示在气溶胶液滴内以比分批溶液相合成中可行的更高温度和更短反应时间连续生产高质量球形、各向异性和混合半导体纳米晶体。(3)将化学反应工程的原理和工具应用到喷雾热解过程中，以研究纳米晶成核和生长的动力学，并设计改进的喷雾热解过程，以生产更高质量的纳米晶体。更广泛的影响：拟议的工作将导致开发新的，连续的，相对高产量的半导体纳米晶体，特别是各向异性和混合纳米晶体的生产过程。 这将通过扩大这种半导体纳米晶体可以考虑的应用范围而产生技术影响。 通过这项工作，两个博士。学生将接受纳米材料气溶胶合成的培训，并培养化学、材料科学和化学工程方面的跨学科技能。 本科生将通过NSF REU计划参与该项目，并通过其他有针对性的计划，如麦克奈尔学者计划和路易斯斯托克斯少数民族参与联盟（LS-AMP）计划。 PI的小组在招募少数民族参与者方面取得了越来越大的成功，这个项目将在这一成功的基础上扩大它，向初中和高中学生和教师推广。

PI: Mark Swihart Institution: SUNY Buffalo Proposal Number: 0652042Title: GOALI: Continuous Production of Semiconductor and Hybrid Nanocrystals by Spray PyrolysisThe PI plans to investigate the possibilities and limitations of spray pyrolysis methods for producing semiconductor and multicomponent nanocrystals of sufficiently small size to exhibit size- and shape-dependent optical and electronic properties. A vast array of potential applications based on these size and shape-tunable properties may be possible, ranging from biological imaging to solar cells and light-emitting diodes. Development of reproducible, controllable, and scalable continuous processes for producing these materials is essential to the realization of these applications. In spray pyrolysis, variants of which will be developed and explored here, a liquid precursor solution is sprayed as a mist of fine droplets (an aerosol) that is heated to induce formation of solid particles. He will study two spray pyrolysis approaches: (1) complete evaporation/vapor phase nucleation mode in which the aerosol serves as a means of delivering high concentrations of moderate volatility precursors into the gas phase, and (2) incomplete evaporation mode with formation of multiple product particles per precursor droplet, in which each aerosol droplet serves as a femtoliter-scale liquid phase reactor that, by virtue of its small size, can be heated or cooled very rapidly and remains uniform in concentration and temperature. The first approach expands on the capabilities of other vapor-phase synthesis approaches by allowing use of lower-volatility and lower-stability precursors than would otherwise be possible. The second approach allows one to extend powerful solution-phase methods to higher temperatures and shorter reaction times than are practical in conventional batch processes in solution.Intellectual Merit: The PI's recent advances in solution phase synthesis of anisotropic and hybrid semiconductor nanocrystals and in spray pyrolysis synthesis of other materials, suggest natural research directions for combining and extending these approaches. This will advance both nanoparticle synthesis capabilities and our understanding of the kinetics of nanocrystal nucleation, growth, and shape evolution. The project goals are to:(1) Establish the extent to which solution-phase methods of producing semiconductor nanocrystals and hybrid nanocrystals can be applied in the vapor-phase via complete evaporation and gas phase reaction of precursors delivered as an aerosol.(2) Demonstrate continuous production of high quality spherical, anisotropic, and hybrid semiconductor nanocrystals within aerosol droplets at higher temperature and shorter reaction times than are feasible in batch solution phase syntheses.(3) Apply principles and tools of chemical reaction engineering to the spray pyrolysis process to investigate the kinetics of nanocrystal nucleation and growth, and to design improved spray pyrolysis processes that produce higher quality nanocrystals.Broader Impact: The proposed work will lead to development of new, continuous, relatively high-throughput processes for the production of semiconductor nanocrystals, particularly anisotropic and hybrid nanocrystals. This will have technological impact by expanding the range of applications for which such semiconductor nanocrystals can be considered. Through this work, two Ph.D. students will be trained in the aerosol synthesis of nanoscale materials and develop cross-disciplinary skills in chemistry, materials science, and chemical engineering. Undergraduates will participate in this project through the NSF REU program, and through additional targeted programs such as the McNair Scholars program and the Louis Stokes Alliance for Minority Participation (LS-AMP) program. The PI's group has had increasing success in recruiting minority participants, and this project will build on this success and expand it with outreach to middle and high-school students and teachers.