Revealing the Mechanisms of Bulk Material Dissolution in Thiol-Amine Solvent Mixtures Toward the Solution Deposition of Chalcogenide Thin Films

非技术性总结：宏电子工业已经成为一个强大的实体，广泛部署薄膜技术，如太阳能电池和平板显示器。这些宏电子应用需要低成本、大面积电子的创新方法，因为驱动器与规模更大、更成熟的微电子工业不兼容。为了降低薄膜宏电子器件的成本并提高其市场潜力，对下一代宏电子器件薄膜沉积和加工的研究必须包括对低温溶液加工的关注。主要研究人员正在研究一种溶剂混合物，用于溶解廉价的散装材料，以制造墨水，在溶液沉积后，在温和的条件下转化为半导体薄膜。该项目的主要目标包括了解散装材料溶解的化学过程，并利用这些信息来存款稳定的新型半导体薄膜，这些薄膜有望用于下一代太阳能电池。该计划还包括一个专门针对当地社区大学生的外联方案。首席研究员正在与喜瑞都社区学院合作，该学院有大量代表性不足的学生，提供材料研究方面的实习机会。这个为期8周的年度外展计划的目标是为这些学生提供STEM研究机会，这些机会在社区学院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。实习校友网络将建立，以保持与实习生在他们完成程序后的正式联系。技术概要：尽管半导体薄膜沉积的发展几十年来，绝大多数的方法需要昂贵的，能源密集的条件。因此，需要开发资本和能量密集度较低的沉积工艺。直接溶解散装材料以产生在温和条件下转化为薄膜的可溶液加工的油墨可以导致显著的成本降低。该项目通过研究用硫醇-胺溶剂混合物通过批量硫属化物、氧化物和金属溶解制备的油墨直接解决了这一挑战。主要研究者正在利用他在无机化学和材料合成方面的专业知识来实现以下目标：（1）了解硫醇-胺溶剂混合物溶解散装材料背后的化学过程。虽然已经证明了大量散装材料在该溶剂混合物中的溶解性，但对溶解机制的了解很少或根本不了解。通过检查产生的分子溶质和影响溶解动力学的化学因素来询问溶解机制。并行地，采用结合Rietveld细化和X射线总散射数据的对分布函数（PDF）分析的双空间方法来监测无定形干燥分子油墨到结晶硫属化物薄膜的热转换。这种方法智能地通知相纯、高质量硫属化物薄膜的溶液处理和结晶。(2)使用硫醇-胺溶剂混合物溶液处理有前途的太阳能转换硫属化物薄膜。现在可与该系统一起使用的大量调色板的油墨被用于溶液处理更新颖的、组成复杂的、多元硫族化物半导体薄膜，其具有适合于太阳能转换的性质，例如最佳带隙、极性晶体结构和具有高热力学稳定性的由地球丰富元素组成的材料。该奖项反映了NSF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。

NON-TECHNICAL SUMMARY: The macroelectronics industry has emerged as a powerful entity with widespread deployment of thin film technologies, such as solar cells and flat panel displays. These macroelectronics applications require innovative approaches to low-cost, large-area electronics, as the drivers are not compatible with the larger and more well-established microelectronics industry. To reduce costs and improve market potential for thin film macroelectronics, research into next-generation macroelectronic thin film deposition and processing must include a focus on low-temperature solution processing. The principal investigator is studying a solvent mixture used to dissolve cheap bulk materials to make inks that, upon solution deposition, convert to semiconductor thin films under mild conditions. The primary goals of this project include understanding the chemistry of bulk material dissolution and leveraging that information to deposit stable semiconductor thin films of novel composition that are promising for next-generation solar cells. Integrated into this plan is an outreach program specifically aimed at local community college students. The principal investigator is partnering with Cerritos Community College, an institution with a large number of underrepresented students, to provide internships on materials research. The objective of this annual 8-week outreach program is to provide these students with STEM research opportunities that are not afforded to them at the community college level, and thereby increase their transfer rate to 4-year institutions. An internship alumni network will be established to maintain formal contact with the interns after they complete the program.TECHNICAL SUMMARY: Despite decades of developments in semiconductor thin film deposition, the vast majority of methods require costly, energy intensive conditions. As such, there is a need to develop deposition processes that are less capital- and energy-intensive. The direct dissolution of bulk materials to yield solution processable inks that convert to thin films under mild conditions can result in significant cost reductions. This project directly addresses the challenge by studying inks prepared by bulk chalcogenide, oxide, and metal dissolution with thiol-amine solvent mixtures. The principal investigator is leveraging his expertise in inorganic chemistry and materials synthesis to meet the following objectives: (1) Understand the chemistry behind the dissolution of bulk materials with the thiol-amine solvent mixture. While a wide scope of bulk materials has demonstrated solubility in this solvent mixture, there is little to no understanding of the dissolution mechanism. The dissolution mechanism is being interrogated through an examination of the resulting molecular solutes and the chemical factors that affect the kinetics of dissolution. In parallel, a dual-space approach that combines Rietveld refinement and pair distribution function (PDF) analysis of X-ray total scattering data is being employed to monitor thermal conversion of the amorphous dried molecular inks into crystalline chalcogenide thin films. This approach is intelligently informing solution processing and crystallization of phase-pure, high-quality chalcogenide thin films. (2) Use the thiol-amine solvent mixture to solution process promising chalcogenide thin films for solar energy conversion. The large palette of inks now available with this system are being used to solution process more novel, compositionally complex, multinary chalcogenide semiconductor thin films with properties amenable to solar energy conversion, such as optimal band gap, polar crystal structures, and materials with high thermodynamic stability comprised of Earth abundant elements. The most promising candidates are being explored in next-generation solar cells.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.