耦合量子点薄膜中光致界面电荷转移动力学特性研究

发布时间：2018-01-03 10:39

本文关键词：耦合量子点薄膜中光致界面电荷转移动力学特性研究　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来,随着量子点中多重激子理论的不断完善以及相关的实验支持,对于具有高量子效率的量子点太阳能电池的研究逐渐成为了国际热点。其中,如何通过界面电荷转移将激子有效拆分并输运至电极这一过程是研究量子点太阳能电池高量子效率成因的关键物理问题。目前,针对光伏器件的实际工作状态,同时用光电及光谱方法在不同时间尺度研究量子点薄膜界面电荷转移动力学特性的实验报道并不多见,而这对于高效光电器件的设计具有非常重要的科学意义。本文以单、双层Cd Se耦合量子点薄膜器件为主要研究对象,以瞬态光电流(TOF)和时间分辨荧光光谱技术为主要实验手段,研究了量子点与受体、不同尺寸量子点之间的界面电荷转移动力学特性,主要包含以下几部分研究工作:首先,根据不同材料的能级匹配结构设计并制备了两种类型的Cd Se耦合量子点薄膜器件。对于含电极的光伏器件,主要关注其长时间尺度下的瞬态光电流特性;另一类仅有量子点和受体的薄膜器件则主要关注其短时间尺度下的时间分辨荧光光谱特性。利用两种实验手段分别在μs和ns量级时间尺度研究界面电荷转移动力学特性,实验结果可以彼此支持。其次,研究了量子点与受体之间的界面电荷转移动力学特性。通过改变原型光伏器件中量子点薄膜的厚度,我们发现TOF信号主要来源于量子点与受体之间发生界面电荷转移后载流子在受体中的输运过程。而无激子阻挡层(受体)器件的TOF信号则表明了量子点与电极之间的界面电荷转移及复合的动力学特性。作为进一步的实验支持,我们采集了相关器件的时间分辨荧光光谱并进行了全局拟合。对于孤立量子点薄膜器件,拟合结果给出了三个荧光组分,而对于量子点/受体薄膜器件,则给出了第四个荧光组分,这个组分被指认为界面电荷转移动力学过程,并获得了相应的动力学参数。最后,研究了不同尺寸量子点之间的界面电荷转移动力学特性。对于双层量子点薄膜光伏器件的TOF实验结果,我们通过分析发现了其中量子点之间界面电荷转移的贡献,并表征了其动力学参数;同时,不同偏压条件下的TOF实验也进一步支持了相关结论。
[Abstract]:In recent years, with the theory of multiple exciton in quantum dots and constantly improve the relevant experimental support for research of quantum dots with high quantum efficiency of the solar battery has gradually become the international hotspot. Among them, how will the interfacial charge transfer exciton effective separation and transport to the electrode of this process is the key problem of physics quantum dot solar cells the causes of high quantum efficiency. At present, according to the actual working condition of photovoltaic devices, the report also used photoelectric and spectral methods at different time points of the quantum scale thin film interfacial charge transfer dynamics is rare, and has very important scientific significance for the design of optoelectronic devices. In this paper, the coupling of quantum double point Cd Se thin film as the main research object, the transient photocurrent (TOF) and time-resolved fluorescence spectroscopy technology as the main means of experiment, Study on the quantum dots and receptor, transfer dynamics of interfacial charge between quantum dots of different sizes, mainly includes the following several parts of research work: first of all, according to the different level of material, structure design and Cd Se coupled quantum dot thin film device with two types of preparation. The photovoltaic device with electrodes, mainly focus on transient light current characteristics of the long time scales; only another kind of quantum dots and receptor thin film device mainly focuses on the short time scale of the time-resolved fluorescence spectral characteristics. By using two kinds of experimental means to transfer the dynamic characteristics in the s and NS magnitude time scales on the interface charge respectively, then experimental results can support each other. Study on the interface, charge transfer between quantum dots and receptor dynamics. Through the change of quantum dots in a photovoltaic device prototype film thickness, we found that the main source of TOF signal Between quantum dots and interfacial charge transfer after carrier receptors in the receptor transport process. Without the exciton blocking layer (TOF receptor) signal device shows that between quantum dots and electrode interfacial charge transfer and complex dynamics. As the experimental support to further, we collect the related devices of the time resolution of fluorescence spectrum and the global fitting for isolated quantum dot thin film devices, the fitting results in three fluorescent components, and for quantum dots / receptor thin film device provides fourth fluorescent components, the components are regarded as interfacial charge transfer kinetics and the corresponding kinetic parameters were obtained. Finally, the interface of the charge transfer of quantum dots of different sizes for the dynamics. The experimental results of TOF double quantum dots film photovoltaic devices, we found the content through the analysis The contribution of the interface charge transfer between the subpoints and the kinetic parameters are characterized. At the same time, the TOF experiment under different bias conditions also further supports the relevant conclusions.

【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O471.1;TM914.4

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