可溶性并苯类有机半导体单晶阵列化组装及其有机场效应晶体管的研究

Due to the potential applications in flexible display, integrated circuits, and sensors, organic field-effect transistors (OFETs) have received focus attention all over the world. Organic semiconductor single crystals (OSSCs), with eliminated grain boundaries and few defects, exhibit a higher carrier mobility than the corresponding amorphous and polycrystalline organic thin films. Therefore, OSSCs are potential building blocks for high-performance OFETs. However, due to the lack of control over the crystal growth, most OSSCs always exist as micrometer- or nanometer-sized crystals and the OSSCs have non-uniform morphology and crystallization orientation, leading to difficulty in large-scale device application. Aiming at these critical issues, this project plans to use high-mobility soluble acenes as research object. We will utilize microchannel template-assisted coating techniques to guide the molecular assembly along the channels and thereby allows achieving highly ordered OSSCs arrays. And the assembly mechanism of OSSC arrays will be systematically studied through in-situ characterization and fluid dynamics simulations. The research of assembly mechanism also provide scientific basis to optimize template structure and coating condition for large-area fabrication of well-aligned OSSC arrays with homogeneous morphologies and pure crystallographic orientation. Based on the realization of OSSC arrays, large-area and high-performance OFETs based on OSSCs will be fabricated, facilitating their application in integrated devices.

有机场效应晶体管是柔性显示、有机电路、传感器的核心组件，因此受到了广泛关注。相比非晶和多晶的有机薄膜，无晶界、缺陷密度低的有机半导体单晶被认为是理想的场效应晶体管材料。然而，由于缺乏对晶体生长的控制，有机半导体单晶通常以形貌和结晶取向随机分布的微纳晶形式存在，这给其规模化器件应用带来了极大的困难。针对上述关键科学问题，本项目以可溶性、高迁移率的并苯类有机分子为主要研究对象，采用微沟道模板辅助涂布技术引导并苯类有机分子沿模板稳定、连续、定向地组装，实现并苯类单晶的阵列化生长；通过原位表征手段结合流体力学模拟，揭示并苯类单晶阵列化组装机制；并以此为研究基础，调整模板结构及涂布条件等参数，最终实现形貌均匀和结晶取向高度一致的并苯类单晶阵列；最后，在此基础上构筑基于可溶性并苯类单晶阵列的高性能有机场效应晶体管及其集成器件，并展示其在反相器等门电路中的应用前景。

本项目针对目前有机半导体单晶有序组装方法获得的晶体覆盖面积低、形貌差异大以及结晶取向不一等问题，造成大规模器件性能波动较大难以满足实际应用的需求。为此，本项目以高迁移率、可溶性并苯类有机半导体为研究对象，发展了晶种取向“漏斗”过滤、毛细管力驱动分子流、液相外延、微通道助力刮涂等多种有机单晶阵列化组装方法，实现了晶圆级（>4英寸）、尺寸波动小于10%、取向一致的有机单晶阵列的可控制备。同时，发展了基于同步辐射光源的XRD表征技术，实现了对大面积范围内有机单晶阵列结构的表征与分析。在此基础上，结合实验与流体动力学模拟阐明了有机分子在微结构下的分子聚集、成核与结晶生长机制，为指导生长方法的设计与调控晶体结构提供了理论与实验指导。最后，基于制得的有机单晶阵列结合器件界面调控手段，最终实现了大面积（厘米级）、高集成度（310 dpi）、高迁移率（16.1 cm2 V-1 s-1）且性能均一的有机场效应晶体管阵列以及高增益的有机单晶门电路。本项目研究期间，共发表SCI收录期刊论文16篇，包括1篇Nature Electronics News & Views文章，4篇Adv. Mater., 3篇Adv. Funct. Mater., 1篇 Mater. Today，申请专利8项，其中8项获得授权，并在国内外学术会议做口头报告6次；培养研究生1名。本项目较好地完成了计划，专利具有应用前景。此后我们还将在该领域继续深入研究，争取更多的成果。