基于柔性纸张衬底的垂直结构有机双电层晶体管研究

Recently, vertical organic field-effect transistors have attracted extensive interest for organic optoelectronic applications because of low cost, flexibility and light weight. Here we aim at developing vertical organic electric-double-layer（EDL）transistors on flexible paper substrate, improving the device performances by using conducting nanorods or nanotubes as the source electrodes and elucidating the operating mechanism. The solid-electrolyte gate dielectrics (nanoporous SiO2, chitosan, and so on) can be fabricated on low-cost paper substrate by traditional PECVD or spin-coating technology. The prepared solid electrolyte gate dielectric, which forms the so-called electric-double-layer (EDL) associated with a high specific capacitance, can be used to achieve low operational voltages (<2V) of transistors. The vacuum deposition and spin-coating technoloy can be used for the preparation of organic semiconductor channel layer (CuPc, C60, P3HT) . The fabrication of the vertical organic EDL transistor arrays on paper can be completed by deposition of the electrodes through the metal shadow mask. The surface characterization of the paper and the cross-sectional image of the completed vertical organic transistor devices will be characterized using field emission scanning electron microscopy (SEM),transmission electron microscope (TEM) and atomic force microscope (AFM). Electrical characterizations of microporous-SiO2 gate dielectric and the vertical transistors on paper will be performed by an impedance analyzer and a semiconductor parameter analyzer.It is very of importance to obtain the property of the EDL and improve the mobility, Ion/Ioff ratio, subthreshold swing, switching speed, surface/interface properties of the vertical organic EDL transistors on paper substrate.

最近，垂直结构有机晶体管具有成本低、柔韧性、重量轻等诸多优点，在有机光电子器件应用领域表现出巨大的应用前景。本申请项目拟在纸张衬底上制备垂直结构有机晶体管、通过使用导电纳米材料源电极改善器件性能、并对垂直结构器件的工作机理给出详细解释。采用微电子工艺传统的PECVD、旋涂技术等在纸张衬底上制备多孔SiO2、壳聚糖等固态电解质作为垂直结构有机晶体管的绝缘层。由于双电层效应，这些固态电解质具有巨大单位电容，使得器件工作电压低于2V。利用真空镀膜技术和旋涂技术制备CuPc，C60以及P3HT等有机半导体薄膜，结合金属掩模技术，利用热蒸发设备沉积源漏电极，研制垂直结构低电压有机纸张晶体管。利用SEM，TEM，AFM等对垂直器件微结构、形貌进行表征，利用先进的器件测试手段分析该类器件的电学特性以及固态电解质双电层特性，优化器件的载流子迁移率、电流开关比、亚阈值斜率、开关速度、表面界面特性关键参数。

本项目针对有机半导体器件的薄膜生长、形貌优化、器件表面界面以及电学输运特性进行深入研究。成功研制低成本、高单位电容（>1F/cm2）、高极化响应速度以及具有低栅漏电流的固态电解质绝缘层（壳聚糖、明胶、离子胶等）。在纸张衬底上制备了高性能柔性有机晶体管以及有机/纳米线光电探测器，其器件最大迁移率达到0.97 cm2/Vs。通过对器件进行相关的分析测试与表征，对该类器件工作机理与电荷输运进行了详细分析与合理的解释。通过弱外延生长获得了高质量的高有序酞青铜薄膜，并制备了高空气稳定性、高迁移率（>0.18 cm2/Vs）、高光响应的有机晶体管以及探测器。并且通过原位KPFM、原位CAFM以及UPS对薄膜的各向异性以及光响应机理进行了详细表征。此外，本项目还对研制了一些列高性能的基于氧化物和纳米线的晶体管以及光电探测器。本项目通过三年的研究工作，各项计划研究工作内容均已完成,达到预定科研目标。在本项目的支持下，目前已经正式发表科研论文16篇，其中以项目负责人为通讯作者的SCI论文13篇，另外有4篇文章投寄到国外SCI源刊杂志，且标注基金资助。