【作者】 李晶；

【导师】 董桂芳；

【作者基本信息】 清华大学 ， 化学， 2016， 硕士

【摘要】 多功能有机薄膜晶体管（OTFT）集OTFT的开关特性与其他功能（例如存储、发光等）于一体,是目前有机/无机半导体材料与功能器件领域研究的热点之一。针对多功能OTFT小型化、便携化的发展趋势,在本论文中,我们创新性地引入摩擦纳米发电机（TENG）将机械力转换为静电势能,代替传统的栅极电压,研究开发了新型多功能OTFT器件。此外,利用铱离子型配合物,开发了绝缘层面发光的晶体管。研究主要包括:1.开发了基于Ta₂O₅的有机摩擦晶体管（OTT）,实现以机械力代替传统栅极电压对沟道电流进行调控。通过对薄膜形貌的分析及对各功能层的优化匹配,成功制备具有良好电学特性和稳定性的器件,其平均阈值电压（V_T）小于1V,开关电流比(I_on/I_off)超过10⁵,在干燥器中保存一年后性能未明显退化。此外,我们实现了OTT对有机发光二极管（OLED）的发光调控应用。2.开发了基于Ta浮栅结构的有机摩擦晶体管存储器（OTTM）,实现对机械摩擦信号的存储。利用Ta浮栅结构增加电荷捕获密度,并用长链聚合物聚甲基丙烯酸甲酯（PMMA）提升器件的抗拉伸性,我们成功制备了高性能柔性器件,其存储窗口(V_MW)达到16.3±0.4 V,开关比超过10⁵,存储时间大于10⁵s,可耐受超过1000次的弯曲测试,在氮气氛围手套箱中保存2个月后仍具有摩擦存储性能。在此基础上,我们分析了OTTM的工作机制并通过耦合柔性OLED,建立全柔性可穿戴接触监控系统,实现了OTTM的实际应用。3.研究基于铱离子型配合物[Ir（dmfpz）₂（dtb-bpy）]PF₆的栅绝缘层,以氧化锌锡（ZTO）为半导体层的晶体管,实现了结构简单、工作电压低、绝缘层面发光的新型器件。利用双电层机理,有效降低器件阈值电压（V_T）至0.85 V。器件迁移率达到48.3 cm² V^-1s^-1,并实现了V_GS与V_DS对发光的调控作用。而后,我们将该方法推广到其它铱离子配合物,基于[Ir（ppy）₂pyim]PF₆,系统研究了掺杂不同浓度的PMMA后对器件性能的影响,同样实现了三个电极对发光的调控。此外,我们分析研究了掺杂与未掺杂器件的工作机制。该研究为未来能够实现集发电、开关调控、存储、显示于一体的多功能有机摩擦晶体管器件打下了一定基础。更多还原

【Abstract】 Multi-functional organic thin-film transistor（OTFT）combines the switching capability of OTFT and other functions（e.g.memory,light-emitting）in a single device,which has been a hotspot in the field of research of organic/inorganic semiconductors and functional devices.The development of multi-functional OTFTs follows a trend of miniaturization and portability.Therefore,in this article,we established novel multi-functional transistors by coupling triboelectric nanogenerators（TENGs）,which were controlled by the contact-induced electrostatic potential of TENGs rather than traditional gate voltages.Furthermore,based on iridium ionic complexes,we proposed novel kinds of transitors giving emission from gate dielectric layers.Our research includes three parts as follows:1.We proposed an organic triboelectric transistor（OTT）based on Ta₂O₅,in which the channel current(I_DS)was modulated by mechanical force instead of traditional gate voltage.Wesuccessfully fabricated high-performance OTT by controlling the film morphology and optimizing different functional layers.The device showed excellent transistor characteristics and stability.The average threshold voltage（V_T）was below 1 Vand the on/off current ratio was over 10⁵,while the performance remained same after one year.Furthermore,the OTT could be used to control light emission of an organiclight-emittingdiode（OLED）.2.We proposed an organic triboelectric transistor memory（OTTM）based on Ta floating gates,in which externally applied touch signals could be memoried.Using Ta floating gate to enhance the trap density and polymethyl methacrylate（PMMA）to improve mechanical stability,we successfully fabricated a high-performance flexible device with a large memory window（16.3±0.4 V）,a high ON/OFF ratio（10⁵）and a long retention time（10⁵s）.The device remained stable after 1,000 iterations of compressive or tensile bending tests,and could still work after 2 months.Then,we discussed the working mechanism of OTTM.Moreover,by coupling with an OLED,we established an all-flexible wearable touch monitoring system for real applications.3.Based on [Ir（dmfpz）₂（dtb-bpy）]PF₆andzinc tin oxide（ZTO）,we designed and fabricated a novel simple-structured light-emitting transistor which gave area-emission from dielectric layer under a low voltage.Owing to the forming of electrochemical double layers,we successfully decreased the threshold voltage（V_T）of the device to 0.85 V,and the charge carrier mobility of the device was over 48.3 cm² V^-1s^-1.The light emission could be controlled through V_GS and V_DS.To prove the wide applicability of our approach,we fabricated similar device based on another iridium ionic complex,[Ir（ppy）₂pyim]PF₆.We carried on systematical research by mixing this complex with different mass concentration ratios of PMMA.Furthermore,we demonstrated the different working mechanisms of the devices with or without PMMA.Our research laided the foundation of the realization of multi-functional organic triboelectric transistor in the future.更多还原