兰州大学机构库 >物理科学与技术学院
基于磷光染料掺杂荧光主体OLED发光层薄膜电输运特性导纳法研究
Alternative TitleInvestigation of charge transport properties of OLED emission-layer-film based on phosphorescent dye doped fluorescent molecule by admittance spectroscopy
王颖
Thesis Advisor刘肃 ; 马东阁
2014-11-30
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name博士
Keyword磷光 掺杂 迁移率 导纳谱 有机电致发光器件 发光层
Abstract重金属铱配合物磷光染料掺杂荧光主体体系是各种磷光发光和荧磷共混发光OLED常用的载流子传输层和发光层。 我们研究了三大薄膜体系中空穴的输运特性,得到了一些有价值的结论。 (一) 研究了空穴迁移率: (1) 纯净的NPB薄膜中器件的迁移率依赖薄膜厚度而变化。(2) (fbi)2Ir(acac)和Ir(ppy)3分别掺杂的TCTA薄膜,迁移率随电场强度的平方根的的变化具有特殊性,其余都随电场强度平方跟的增加而减小。 (二) 研究了单空穴器件的C-V特性。结果表明: (1) 基于有机薄膜NPB: Ir(piq)3、TCTA:(fbi)2Ir(acac)、TCTA:Ir(ppy)3、TCTA: Ir(piq)3、mCP:FIr6和mCP:FIrpic的单空穴器件具有类似的C-V特性。 (三) 研究了单空穴器件的电导-电压特性。结果表明掺杂浓度不同器件的电导不同,即器件的开启电压不同,提高器件的电导即降低了器件的开启电压: (四) 我们发现在结构为ITO/MoO3/荧光主体:磷光染料/MoO3/Al的一些器件中,负微分电纳频率谱会出现两个特征峰。我们认为,有机层与复合阴极之间形成了肖特基势垒,空穴在传输过程中经历了两个空间电荷限制传导区域。 (五) 拓展了Motte-Schottky方法在有机电子领域中的应用—确定复合阴极功函数。 (六) 基于复合区复合速率密度匀均分布的近似,建立了单层双注入载流子器件的导纳法计算迁移率的模型。据此模型可根据测量的AS数据计算空穴和电子迁移率之和。
Other AbstractIn present dissertation, hole transport in phosphorescent dyes, bis(2-(9,9-diethyl-9H-fluoren-2-yl)-1-phenyl-1Hbenzoimidazol-N,C3) iridium(acetylacetonate) [(fbi)2Ir(acac)], tris(2-phenylpyridine) iridium [Ir(ppy)3], tris[1-phenylisoquinolinato-C2,N]iridium [Ir(piq)3], bis(4,6-difluorophenyl)-pyridina-to-N,C20]-picolinate (FIrpic) and bis(4’,6’-difluorophenylpyridinato)tetrakis(1-pyrazolyl)borate (FIr6)] doped host molecule films of [N,N-diphenyl-N,N-bis(1-naphthylphenyl)-1,1 -biphenyl-4 ,4 -diamine (NPB), 4,4,4-tri(Ncarbazolyl)triphenylami (TCTA) and 4,4’-N,N’-dicarbazole-biphenyl (mCP)] are systematically investigated by using admittance spectroscopy (AS) method and important conclusions are drown. 1. Hole mobility of phosphorescent iridium complexes, bis(2-(9,9-diethyl-9 H-fluoren-2-yl)-1- phenyl-1Hbenzoimidazol-N,C3) iridium (acetylacetonate) [(fbi)2Ir(acac)]、Tris(2-phenylpyridine) iridium [Ir(ppy)3] and tris[1-phenylisoquinolinato-C2,N]iridium [Ir(piq)3] doped fluorescent host NPB and TCTAfilms, as well as FIrpic and FIr6 doped mCP film, were investigated. Important results are obtained. (1) For thicker films (>300 nm), the electric field dependence of hole mobility is, as expected, positive, i.e., the mobility increases exponentially with the squareroot of electric field. However, for thin films (<300 nm), the electric field dependence of hole mobility is negative, i.e.the hole mobility decreases exponentially with the electric field. (2) For (fbi)2Ir(acac) doped NPB film, the dopant molecule function as hole traps, and lower the hole mobility. For thickness at the order 100 nm, the hole mobility decreases exponentially with the square root of the electric field. (3) For Ir(piq)3 doped NPB film around 100 nm thick, the mobility decreases exponentially with the square root of the electric field,. In general, the variation of mobility with the doping concentration is insignificant. For an applied bias of 9 V, the mobility varies in the range of 1.310-52.410-5 cm2/Vs for a wide doping concentration range of from 1.0 wt.% to 9.0 wt.%. In addition, the dependence of mobility on the temperature is weak. For a doping concentration of 3.0 wt.% and an electric field of 5×105 V/cm, the mobility varies in the small range of 1.8×10-5~2.1×10-5 cm2/Vs in a large temperature range of from 78K to 300K. (4) For (fbi)2Ir(acac) and Ir(ppy)3 doped TCTA films, in the case of light doping, the mobility decreases with the square root of the electric field, w...
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Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/229790
Collection物理科学与技术学院
Recommended Citation
GB/T 7714
王颖. 基于磷光染料掺杂荧光主体OLED发光层薄膜电输运特性导纳法研究[D]. 兰州. 兰州大学,2014.
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