【作者】 王立国；

【导师】 张怀武；

【作者基本信息】 电子科技大学 ， 电子科学与技术， 2012， 博士

【摘要】 有机电子器件具有一系列优异特性并展现出巨大的应用潜力，近年来受到国内外学术界和产业界的广泛关注。但它们同时表现出的运转速度慢、工作效率低、使用寿命短等缺点也严重阻碍了其进一步发展。要从根本上解决这些问题，使有机电子器件更好地为我们所用，就需要进一步提高有机半导体材料的性能，设计更合理的有机电子器件结构。而要达到这一目的，就要求我们必须正确认识有机半导体材料及有机电子器件的电荷输运问题，这对有机半导体材料的合成及有机电子器件的设计具有重要指导意义。本论文正是基于这一主题，深入研究了有机半导体材料及器件的电荷输运及相关的电性质，获得了一些有益于有机半导体材料合成及有机电子器件设计的重要结果。论文的主要工作和创新点如下：一、提出了一种特别的求解描述空间电荷限制电流（SCLC）耦合方程的非均匀离散化数值计算方法。基于这种数值方法和扩展高斯无序模型（EGDM），计算了基于有机半导体聚合物MEH-PPV和P3HT的空穴型二极管J V特性，证实了数值计算结果同实验测试数据相当吻合。此外，进一步计算和分析了器件的J V特性随边界载流子浓度的变化关系以及载流子浓度和电场强度随有机活性层中位置的分布情况。结果表明：太大或太小的边界载流子浓度将导致不正确的J V特性，载流子浓度为有机层中位置的减函数而电场强度为位置的增函数，载流子浓度的最大值和场强的最小值出现在界面处。二、在W. F. Pasveer等人提出的只考虑了非阿列纽斯温度依赖关系的扩展高斯无序模型的基础上，全面考虑阿列纽斯温度依赖关系和非阿列纽斯温度依赖关系对载流子迁移率的影响，提出了一种基于两种温度依赖关系的载流子迁移率依赖于场强、温度及载流子浓度的统一理论模型，并证实了该模型能更好地描述有机电子材料及器件的电荷输运，尤其在高载流子浓度和高场强区域。此外，将该模型应用于基于有机半导体聚合物NRS-PPV、OC1C10-PPV及MEH-PPV的空穴型器件，证实了使用该模型计算的J V特性同实验测试结果非常吻合，表明改进模型相对于初始模型可以更好地描述有机电子器件的J V特性，更好地俘获了有机电子材料及器件的电荷输运本质，更适用于有机半导体材料及器件电荷输运及相关电性质的研究。三、实验上制备了基于有机小分子半导体NPB的器件，测试了不同厚度器件室温下的J V特性，证实了改进模型仅用一组模型参数就能同时描述不同厚度器件的J V特性；其次，将改进模型应用于基于聚芴PFO的空穴型器件，证实了改进模型可以仅用一组模型参数就极好地描述相同厚度不同温度或相同温度不同厚度的PFO基空穴型器件的J V特性；最后，将改进模型应用于基于聚噻吩类有机半导体P3HT的空穴型器件，结果显示改进模型很好地描述了P3HT基空穴型器件的J V特性。所有这些结果表明改进模型非常适合于研究各类有机半导体材料的电荷输运。更多还原

【Abstract】 In the past decade organic electronic devices have been extensively studied due totheir good properties and potential applications in many fields. However, their defects inpractical operation hamper progress toward the next step, such as the slow operationspeed, low work efficiency, short service life and so on. In order to slove these problem,people should synthesize better organic electronic materials and further improve thedevice structure. To achieve this purpose, people should understand the charge transportin organic electronic materials and devices properly. In this dissertation, we study thecharge transport and electrical properties in organic electronic materials and devices,and obtain some important results that allow the rational design of organic electronicmaterials and devices. Some important and valuable results which bring forth some newideas are listed as follows:1. A particular numerical method adopting the uneven discretization and NewtonIteration Method to solve the coupled equations describing the space-charge limitedcurrent (SCLC) in conjugated polymers is proposed. Based on this numerical methodand the extended Gaussian disorder model (EGDM), we calculate the current-voltage(J V) characteristics of MEH-PPV-based and P3HT-based hole-only devices, anddemonstrate that the numerical results are in good agreement with experimentalmeasurements. Furthermore, we calculate the variation of J Vcharacteristics withthe boundary carrier density and the distribution of charge-carrier density and electricfield with the distance to the interface. It is shown that the numerically calculated carrierdensity is a decreasing function of the distance and numerically calculated electric fieldis an increasing function of the distance. The maximum of carrier density and theminimum of electric field appear near the interface.2. Based on the extended Gaussian disorder model (EGDM) introduced by Pasveeret al, we propose an improved unified description of the dependence of the chargecarrier mobility on temperature, carrier density and electric field by considering theArrhenius temperature dependence ln()1/Tand non-Arrhenius temperaturedependenceln()1/T2together, and demonstrate the improved model can better describe the charge transport in organic electronic materials and devices, especially athigh carrier density and high electric field. In addition, we calculate the current-voltage(J V) characteristics of NRS-PPV-based, OC1C10-PPV-based and MEH-PPV-basedhole-only devices and demonstrate that the numerical results are in good agreement withexperimental measurements. These results indicate the improved model captures thephysical essence of the charge transport in organic electronic materials and devices, andis more applicable for organic electronic materials and devices than the original model.3. The devices based on the organic small molecule material NPB were fabricated,and the measured J Vcharacteristics were presented. It is demonstrated that theJ Vcharacteristics of various thickness at room temperature can be excellentlydescribed by the improved model only using a set of parameters. Furthermore, we studythe charge transport of PFO-based hole-only devices by using the improved model, anddemonstrate the temperature dependent and thickness dependent J Vcharacteristicscan be excellently described with a set of same parameters. Moreover, we further studythe charge transport of P3HT-based hole-only devices by using the improved model, anddemonstrate that the J Vcharacteristics can be better described by the improvedmodel than the original model. All the results indicate that the improved model isapplicable for various organic semiconductors.更多还原