高分子绝缘单晶的制备及其在有机单晶晶体管的应用

Organic field-effect transistors (OFETs) are interface devices where charges transport in OFETs take places within several monolayers of the semiconductor near the surface of the gate dielectrics. On the side of semiconductor, single-crystalline materials have boosted up the electron transport properties. In principle, usage of single crystals on the dielectric side of the interface will greatly improve the device performance. In this proposal, we aim to grow large-area flat lamellar polymer single crystals so that they can use to replace the widely-used disordered gate dielectrics in the OFETs. These polymer single crystals will be interfaced onto single crystals of organic semiconductors to study the charge transport at the highly ordered interfaces. Specifically，the research objective of this proposal is to elucidate the mechanisms by which the size of the lamellar polymer single crystals is limited, to understand the nature of the traps at the polymer single crystals and how they interact with electrons, and to achieve high-quality electron transport interfaces. Based on this original innovation following the combination of the frontiers of organic electronics and polymer crystallography, we believe this work will, very possibly, lead to novel approaches to constructing high-performance OFETs and motivating the development of polymer crystallography.

有机场效应晶体管的电子传输介质是半导体和绝缘体的界面。该界面中，半导体一侧的有序化已经带来了电子传输性质的飞跃，而界面另一侧的绝缘体的有序化，在理论上，将实现器件性能的再次飞跃。本申请项目以构建有序传输界面为目标，拟以绝缘高分子片状单晶取代目前采用的无序绝缘体材料，发展大面积、平整的高分子片状单晶的制备新策略，进而，与有机半导体单晶进行有序复合，制备基于单晶绝缘体/单晶半导体的有序传输界面，阐明电子在单晶/单晶界面上的运动规律。深入探索高分子片状单晶生长的尺寸限制机制，突破大面积片状单晶的制备瓶颈；研究高分子片状单晶中的缺陷结构及其对传输电子的影响规律，揭示缺陷产生和控制的机制，获得高质量的电子传输界面。该思路整合了有机电子学和高分子结晶学两个领域的前沿研究，开展源头创新的学科交叉，具有首创性和先进性，有望探索出高性能有机场效应晶体管制备的新途径，同时带动高分子结晶学领域的发展。

本项目以制备高分子片状单晶、研究其介电性质、实现其作为绝缘层在晶体管中的应用为目标，主要开展了以下3方面研究：第一，调控高分子单晶生长的动力学条件，实现大尺寸、表面平整的片状单晶。特别是，所制备的聚乙烯（PE）片状单晶的宽度近100μm，厚度为11.75 ± 0.54 nm，长程有序，表面平整，不存在螺位错引起的晶体台阶，适用于进一步的电学研究。第二，基于PE片状单晶，构建出金属-绝缘体-金属电容器，首次测量出PE片状单晶在厚度方向的介电常数2.14 ± 0.07。第三，基于PE绝缘片状单晶和有机半导体单晶，构筑单晶/单晶界面导电沟道，实现了晶体管器件，空穴迁移率接近1 cm2/Vs。.以上成果，特别是大面积平整高分子片状单晶的制备方法的建立，预示着进一步将高分子片状单晶作为电子材料研究和应用的可能性。.基于该项目的研究，项目负责人培养了八名博士和一名硕士，同时以通讯/共同通讯作者身份在Macromolecules、Acc. Chem. Res.、JACS等杂志上发表20篇论文。.