RUI: Organic Vapor-Liquid-Solid Deposition

有机分子晶体（OMC）的薄膜由于其科学上令人感兴趣和潜在有用的性质而引起了广泛的关注，其应用范围从机械柔性电路到廉价的光致发光器件、发光二极管和化学传感器。 然而，由于OMC的性能是非常敏感的结构缺陷，域的大小，和晶体取向，制备高品质的薄膜与控制的微观结构组织的技术有利的条件下，长期以来一直是一个瓶颈，走向实际应用和更好地控制的基础研究。 这项研究将探索一种新的方法来制备OMC薄膜，称为有机气液固（OVLS）沉积。 OVLS结合了气相沉积与使用液体或液晶基质的溶液相生长的方面，与常规物理气相沉积技术相比提供了若干优点。这些包括在环境压力和温度下进行沉积的能力，与各种分子结构单元和溶剂化学的相容性，以及对生长习性、膜形态和结晶取向施加更大控制的能力。 简而言之，OVLS沉积具有改善对几个最重要的膜生长变量的控制的潜力，同时在有利于技术开发和对成核和生长的基本理解的条件下操作。这项研究由NSF的固态和材料化学计划支持，将研究OVLS沉积，以更详细地了解有机材料中的成核和生长机制，并将这种理解应用于探索器件应用，同时为10-15名本科化学和物理专业的学生提供科学研究的实践介绍。技术概述分子晶体对于从制药到塑料电子的许多应用都很重要。 例如，在塑料半导体中-碳基分子正在积极研究作为硅电子产品的潜在低成本替代品-电导率取决于分子如何在晶体中组合在一起，晶体的形状和大小以及其他结构细节。 因此，对晶体结构的更好控制有朝一日可能会导致电子器件的改进。 此外，人们希望能够使用低成本的处理技术来生长和控制结晶，这意味着从目前使用的高真空、高温方法过渡到压力和温度的不太苛刻的环境条件。 这项研究由NSF的固态和材料化学计划支持，旨在开发这种方法，并使用它们来进行晶体生长和结构的基础科学研究，同时研究它们在塑料晶体管等电子器件中的可能应用。 该研究还将为10- 15名本科生提供先进材料和科学研究方面的实践培训，帮助激励和培养下一代科学家。

TECHNICAL SUMMARYThin films of organic molecular crystals (OMCs) have drawn widespread attention for their scientifically interesting and potentially useful properties, with applications ranging from mechanically flexible circuitry, to inexpensive photovoltaics, light emitting diodes, and chemical sensors. However because the properties of OMCs are extremely sensitive to structural imperfections, domain size, and crystallographic orientation, preparation of high quality thin films with controlled microstructural organization under technologically favorable conditions has long been a bottleneck toward practical applications and better controlled fundamental studies. The proposed research will investigate a new approach for fabricating OMC films called organic vapor-liquid-solid (OVLS) deposition. OVLS combines aspects of vapor-phase deposition with solution-phase growth using a liquid or liquid crystalline matrix, offering several advantages compared to conventional physical vapor deposition techniques. These include the ability to perform deposition at ambient pressure and temperature, compatibility with a wide range of molecular building blocks and solvent chemistries, and the ability to exert greater control over growth habit, film morphology, and crystallographic orientation. In short, OVLS deposition has the potential for improved control over several of the most important film growth variables while at the same time operating under conditions favorable for technological exploitation and basic understanding of nucleation and growth. This research, supported by the Solid State and Materials Chemistry program at NSF, will study OVLS deposition to develop a more detailed fundamental understanding of nucleation and growth mechanisms in organic materials and apply that understanding to explore device applications, while providing hands-on introduction to scientific research for 10-15 undergraduate chemistry and physics majors.NON-TECHNICAL SUMMARYMolecular crystals are important for many applications, from pharmaceuticals to plastic electronics. For example, in plastic semiconductors - carbon-based molecules that are being actively researched as potential lower-cost replacements for silicon electronics - electrical conductivity depends on how the molecules pack together in crystals, the shapes and sizes of the crystals, and other structural details. Consequently, better control over crystal structure could someday lead to improved electronic devices. Additionally, one would like to be able to grow and control crystallization using low-cost processing techniques, which means transitioning from high vacuum, high temperature methods used today to less severe ambient conditions of pressure and temperature. This research, supported by the Solid State and Materials Chemistry program at NSF, is aimed at developing such methods, and at using them to perform fundamental scientific studies of crystal growth and structure, while investigating their possible application in electronic devices like plastic transistors. The research will also provide hands-on training in advanced materials and scientific research to 10- 15 undergraduates, helping inspire and prepare a future generation of scientists.