金—二氧化钛纳米粒子系统中飞秒量级电子寿命的研究

发布时间：2018-03-10 23:19

本文选题：等离激元太阳能电池　切入点：Au-TiO_2纳米粒子混合体　出处：《长春理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：太阳能作为一种绿色环保、储量丰富、分布广泛的新能源,太阳能的转换存储设备的研发逐步成为研究的热点。目前,传统太阳能电池仍存在生产成本高、太阳光谱利用范围窄等缺点。基于等离激元的新一代太阳能电池具有吸收波长范围宽、吸收截面大等特点,克服了传统太阳能电池太阳能利用率低的缺点。但是,等离激元太阳能电池仍处于研究的初期阶段,其光电转化效率较低,而延长材料的电子寿命对提高其光电转化效率有重要意义。本文针对可应用于等离激元太阳能电池的Au-TiO_2纳米粒子混合体中的电子转移过程展开研究。首先,通过对比相同激发光条件下TiO_2纳米粒子和Au-TiO_2纳米粒子混合体的电子产额,确认Au-TiO_2纳米粒子混合体中发生了从Au纳米粒子到TiO_2纳米粒子的电子转移过程。并通过Au中电子激发、电子由Au向TiO_2转移及TiO_2中的辐射等过程的定性描述,阐明电子转移的物理机制。其次,由Au纳米粒子和TiO_2纳米粒子的多光子电子辐射过程与波长的相关性,得到Au、TiO_2粒子中多光子电子辐射的阶数,并确定了Au纳米粒子的功函数大约在4.65eV~4.71eV范围之内,TiO_2纳米粒子发生多光子电子辐射过程所需的最小能量在4.59eV~4.65eV范围之内。这为接下来的利用飞秒激光泵浦-探测技术测量Au-TiO_2纳米粒子混合体的电子寿命打下了基础。最后,实验上将光辐射电子显微技术(PEEM)与飞秒时间分辨多光子电子辐射泵浦-探测技术相结合,根据Au纳米粒子、TiO_2纳米粒子以及Au-TiO_2纳米粒子混合体中电子的激发、转移及辐射过程,测量了Au纳米粒子、TiO_2纳米粒子以及Au-TiO_2纳米粒子混合体的电子寿命。发现Au纳米粒子中间态电子以及TiO_2纳米粒子和Au-TiO_2纳米粒子混合体的导带电子都存在快速以及缓慢衰变的两个过程。获得Au-TiO_2纳米粒子混合体中Au纳米粒子和TiO_2纳米粒子电子寿命的基础数据,对于深入理解Au-TiO_2纳米粒子混合体中的电子转移过程,进而提升其光电转化效率至关重要。
[Abstract]:Solar energy as a kind of green environmental protection, rich in reserves, widely distributed new energy, the research and development of solar energy conversion storage devices has gradually become a hot spot. At present, traditional solar cells still have high production costs. The new generation solar cells based on isometric elements have the advantages of wide absorption wavelength range and large absorption cross section, which overcome the disadvantages of low solar energy utilization rate of traditional solar cells. The isobaric solar cells are still in the initial stage of study, and their photoelectric conversion efficiency is low. Prolonging the electron lifetime of the material is of great significance to improve its photoelectric conversion efficiency. In this paper, the electron transfer process in the Au-TiO_2 nanoparticle mixture which can be applied to the isopulticidal solar cells is studied. By comparing the electron yields of TiO_2 nanoparticles and Au-TiO_2 nanoparticles under the same excitation light conditions, the electron transfer process from au nanoparticles to TiO_2 nanoparticles was confirmed. The physical mechanism of electron transfer from au to TiO_2 and radiation in TiO_2 is described qualitatively. Secondly, the correlation between multiphoton electron radiation process and wavelength of au nanoparticles and TiO_2 nanoparticles is discussed. The order of multiphoton electron radiation in Auttio _ 2 particle is obtained. The work function of au nanoparticles is determined to be within the range of 4.65 EV ~ 4.71 EV and the minimum energy required for multiphoton electron radiation of TiO2 nanoparticles is within the range of 4.59 EV ~ 4.65 EV. This is the following technique using femtosecond laser pumping and detection. The measurement of electron lifetime of Au-TiO_2 nanoparticles has laid the foundation. Finally, The experiment combines photoemission electron microscopy (PEEM) with femtosecond time-resolved multiphoton electron pumping and detection technology. According to the excitation, transfer and radiation process of electrons in au nanoparticles TiO2 nanoparticles and Au-TiO_2 nanoparticles, The electron lifetime of au nanoparticles TiO _ 2 nanoparticles and Au-TiO_2 nanoparticles were measured. It was found that the electrons in the intermediate states of au nanoparticles and in the mixtures of TiO_2 nanoparticles and Au-TiO_2 nanoparticles were fast and slow. Two processes of slow decay. The basic data of electron lifetime of au nanoparticles and TiO_2 nanoparticles in Au-TiO_2 nanoparticles are obtained. It is very important to understand the electron transfer process in the Au-TiO_2 nanoparticles and improve the photoelectric conversion efficiency.
【学位授予单位】：长春理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;TM914.4

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