tert-Butyl Chalcogenides as Useful Synthetic Tools for the Synthesis and Surface Modification of Semiconductor Nanocrystals

叔丁基硫属化物作为半导体纳米晶体合成和表面改性的有用合成工具

• 批准号: 1205712
• 负责人: Richard Brutchey
• 金额: $ 34.5万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1205712&HistoricalAwards=false
• 关键词: tert; Butyl; Chalcogenides; Useful; Synthetic

TECHNICAL SUMMARYThe goal of this research funded by the Solid State and Materials Chemistry program is to utilize general and rational synthetic methods for the solution-phase synthesis of semiconductor nanocrystals. The PI developed a facile, low-temperature synthesis method to make semiconductor nanocrystals using thermally (and photolytically) unstable di-tert-butyl dichalcogenide precursors in the presence of readily available metal salts. This method allows for the synthesis of a wide variety of semiconductor nanocrystals, and the high level of kinetic control offered by this approach has been instrumental in the discovery of several new crystal phases of semiconductor nanocrystals. This project will focus on the controlled synthesis of SnSe and Cu2SnSe3 nanocrystals and their derivatives using this synthesis method. These IV-VI and I-IV-VI semiconductors posses band gaps (Eg = 1.0-1.5 eV) in the optimal range for solar energy conversion, in addition to having high absorption coefficients, high carrier mobilities, and being comprised of relatively earth abundant elements; however, neither of these systems has been explored in great detail with respect to well-defined nanocrystals or solar cells. Once in hand, efforts will be placed on removing the insulating ligand shell from the nanocrystal surface and replacing it with small, thermally labile ligands that can still provide enough colloidal stability to form usable nanocrystal inks. These inks will be cast to give nanocrystal films, which upon mild thermal annealing will yield inorganic films that are largely devoid of insulating organic material. The efficacy of the ligand exchange will be rapidly screened using solid-state device and photoelectrochemical measurements, and the most promising nanocrystal/ligand combinations will be further explored in all-inorganic nanocrystal solar cells.NON-TECHNICAL SUMMARYDespite over fifty years of developments in the field of solid-state and materials chemistry, there are still only a limited number of ways to rationally and reproducibly synthesize inorganic materials - the majority of which require energetically costly and harsh conditions. As such, there is a need to develop new methodologies, using rational chemical design principles, for the sustainable synthesis of materials under inexpensive and scalable conditions. This will ultimately enable a 'materials by design' approach to be taken, in which new functional materials can be rationally synthesized to meet specific applications. The PI will utilize a method developed in his research group for the kinetically controlled, low-temperature synthesis of semiconductor nanocrystals. These nanocrystals can be dispersed as an ink, and deposited as films for solar cell active layers using extremely inexpensive methods. Particular focus will be placed on the synthesis of nanocrystals with optimal band gaps for solar energy conversion that are also comprised of earth abundant and sustainable elements. Integrated into this research plan is an outreach program specifically aimed at local community college students. The community college student demographic is among the least targeted in traditional chemistry outreach programs; however, the greater Los Angeles area is home to the largest number of community college students in the United States. The PI has partnered with Cerritos Community College, an institution with a large number of underrepresented students, to provide internships on solar cell research. The objective of this annual 8-week outreach program is to provide these students with research opportunities that are typically not afforded to them at the community college level, and thereby increase their transfer rate to 4-year institutions.

本研究由固态和材料化学计划资助，其目标是利用一般和合理的合成方法进行半导体纳米晶体的液相合成。 PI开发了一种简便的低温合成方法，在容易获得的金属盐的存在下，使用热（和光解）不稳定的二叔丁基二硫属化物前体来制造半导体纳米晶体。 该方法允许合成各种各样的半导体纳米晶体，并且由该方法提供的高水平的动力学控制有助于发现半导体纳米晶体的几种新晶相。 本项目将集中于使用这种合成方法控制合成SnSe和Cu2SnSe3纳米晶体及其衍生物。 这些IV-VI和I-IV-VI半导体除了具有高吸收系数、高载流子迁移率和由相对丰富的元素组成之外，还在太阳能转换的最佳范围内具有带隙（Eg = 1.0 - 1.5eV）;然而，这些系统都没有关于明确定义的纳米晶体或太阳能电池进行详细探索。 一旦到手，将努力从油墨表面去除绝缘配体壳，并用小的、热不稳定的配体代替它，这些配体仍然可以提供足够的胶体稳定性以形成可用的油墨。 这些油墨将被浇铸以得到绝缘膜，其在温和的热退火后将产生基本上不含绝缘有机材料的无机膜。 配体交换的功效将使用固态装置和光电化学测量来快速筛选，并且最有前途的双金属/配体组合将在全无机双金属太阳能电池中被进一步探索。非技术概述尽管在固态和材料化学领域有五十多年的发展，仍然只有有限数量的方法来合理地和可重复地合成无机材料-其中大多数需要高能量和苛刻的条件。 因此，需要开发新的方法，使用合理的化学设计原则，在廉价和可扩展的条件下可持续地合成材料。 这将最终使“材料的设计”的方法，其中新的功能材料可以合理地合成，以满足特定的应用。 PI将利用他的研究小组开发的一种方法，用于动力学控制，低温合成半导体纳米晶体。 这些纳米晶体可以作为油墨分散，并使用非常便宜的方法沉积为太阳能电池活性层的膜。 特别的重点将放在纳米晶体的合成与太阳能转换的最佳带隙，也包括地球丰富和可持续的元素。 纳入这项研究计划是一个外展计划，专门针对当地社区大学的学生。 社区大学的学生是传统化学推广计划中最不具针对性的人群之一;然而，更大的洛杉矶地区是美国社区大学学生人数最多的地区。 PI与Cerritos社区学院合作，该学院拥有大量代表性不足的学生，提供太阳能电池研究的实习机会。 这个为期8周的年度外展计划的目标是为这些学生提供研究机会，这些机会通常在社区大学水平上无法提供给他们，从而提高他们到4年制院校的转学率。