【作者】 赵幸家；

【导师】 徐蔚青； 郑以松；

【作者基本信息】 吉林大学 ， 凝聚态物理， 2011， 硕士

【摘要】 近年来,有机半导体材料发展迅速,尤其是在太阳能电池、发光二极管和场效应管等领域的应用更是受到普遍的关注。为了进一步合理的改善器件的结构和有效的提高器件的光电转化效率,必须对材料本身的特性作深入的学习和研究。迁移率是能够反映半导体材料自身特性的重要参数之一,准确的测量这一参数,对有机材料的筛选及材料的分子结构改良,有机太阳能电池结构的优化以及深入探讨有机材料内部电子、空穴的传输动力学问题等都具有重要的指导意义。本论文针对有机半导体材料迁移率较低,难以测量的特点,分析现有的实验方法并结合实验室已有的设备条件,最终选用以飞行时间方法为指导思想搭建迁移率测试系统,对有机材料迁移特性进行准确测量,从而对测试的半导体材料给出有效的表征。论文中主要的工作内容和所取得的结论如下：1.根据飞行时间方法的原理搭建测试系统,对系统的参数,如激光波长、激光能量、取样电阻等进行细致的分析和研究。实验中以光电材料NPB为标准样品,蒸镀8μm的有机薄膜,对系统参数进行优化和检验。实验结果表明十几个微焦的激光能量可以实现有机材料的薄层激发；取样电阻在1.5KΩ以内对渡越时间基本没有影响。最后在室温空气中,电场强度为1.1×105V/cm的条件下本系统测量NPB的空穴迁移率为6.18×10-4cm2/Vs,这一结果与以报道的实验结果十分接近,证明测得数据准确可靠,该套测试系统具有很好的精确性。2.利用自行搭建的这套系统对当前应用较多的空穴传输材料聚3-己基噻吩(P3HT)进行了迁移率的测量。以氯仿为溶剂配置10mg/ml的P3HT溶液,滴涂成膜厚度9.94μm。在电场强度5×104V/cm的条件下,测得空穴迁移率为3.8×104cm2/Vs。另外我们还测量了不同电场强度下该聚合物的空穴迁移率,结果表明在2×104V/cm～1×105V/cm电场范围内,P3HT的空穴迁移率与电场强度之间具有负电场依赖性,这是由于P3HT成膜后分子的空间无序程度比能量无序程度大造成的。3.我们也测量了四种新合成的有机化合物的空穴迁移率,在大约105V/cm的电场条件下测量四种材料的迁移率分别为7.8×10-4cm2/Vs,7.0×10-4cm2/Vs,5.6×10-4cm2/Vs和3.4×10-4cm2/Vs。与同条件下NPB的迁移率对比表明几种新型化合物具有较好的空穴传输特性,可以作为改良器件性能的功能材料。更多还原

【Abstract】 In recent years, organic semiconductor materials have developed rapidly and received concern attention, especially in the filed of solar cells, organic light emitting diodes and field effect transistor. To further improve the device structure and the efficiency of photoelectric conversion, the characteristics of the materials must be in depth study and research. As one of the important parameters of semiconductor materials, carrier mobility is able to reflect their characteristics. Accurate measurement of mobility, we can choose organic materials well, improve the molecular structure, make more perfect organic solar cell and research the electron or hole transport dynamics.It is difficult to measure for low mobility of organic semiconductor. So in this thesis, with the existing methods and our laboratory conditions, we decide to build a test system by the method of Time-of-FIight. Then we can achieve accurate measurement of organic materials mobility.The main works and conclusions are listed as following:1. We build the test system according to the method Time-of-Flight and then analysis the system parameters, such as laser wavelength, laser energy and sample resistor. In the experiment, NPB is a standard photoelectric material, deposited a film with 8μm. The results show that it is a little impact on transit time when laser energy and resistance are limited in a dozen micro-focus,1.5kΩFinally, in the air and room temperature, we get the hole mobility of NPB is 6.18×10-4cm2/Vs at a electric field 1.1×105V/cm. This result is in good agreement with the value witch is reported before. So our test system has good accuracy.2. With the test system, we measure the hole mobility of poly(3-hexylthiophene)(P3HT) which is widely used in photovoltaic devices. We drop-cast P3HT films 9.94μm from chloroform solution(10mg/ml) onto indium tin oxide(ITO) glass. The hole mobility is 3.8×10-4cm2/Vs at a electric field 5×104V/cm. In addition, we also measured the hole mobility of the polymer under various electric field. The results show that within electric field from 2×104V/cm to 1×105V/cm, the mobility has a negative electric field dependence. This is because the spatial disorder parameter exceeds the energetic disorder parameter.3. We also measured the hole mobility of four new kind organic compounds, their mobility is 7.8×10-4cm2/Vs,7.0×10-4cm2/Vs,5.6×10-4cm2/Vs and 3.4×10-4cm2/Vs at about electric field 105V/cm. Compared these value with NPB under the same conditions, the result show that the four compounds have good hole transport property, they can be used to improve device performance.更多还原