有机无机杂化钙钛矿单晶中的光生载流子扩散和复合动力学研究

发布时间：2018-09-13 16:58

【摘要】：有机无机杂化钙钛矿材料CH3NH3PbX3(MAPbX3, X=Cl, Br, I)由于具有高载流子寿命、高吸收系数、高电荷迁移率(扩散系数)等优良特性,在太阳能电池和其他光电器件等方面展现出广阔的应用价值,成为现如今炙手可热的研究热点材料之一。纳米结构的此类单晶材料(如纳米线和纳米片)保留此类材料的优越光物理性质,其微纳尺寸也使得该类材料在微型光电/光学器件等领域具有广泛的应用价值。本文利用液相法合成了不同卤素的有机无机杂化钙钛矿单晶,通过一系列表征,我们确定得到高质量的MAPbX3(X=Br,I)单晶。通过自行构建的荧光扫描时间分辨荧光成像系统,完成了对微米级钙钛矿单晶的载流子扩散系数的定量测量,这种方法同样可以应用到其他光电材料的检测中。另一方面,通过使用激光／荧光扫描共聚焦显微镜测量局域发光动力学和模拟单个MAPbI3单晶中的载流子扩散过程,我们发现当钙钛矿材料在没有均匀激发情况下,快速的载流子扩散过程会加快局域光致发光动力学过程。结果表明,在钙钛矿单晶中根据光致发光动力学过程来解析载流子寿命时,必须要排除载流子扩散的影响。此外我们比较了PbCl2和MACl提供的Cl源对合成MAPbBr3单晶的影响,发现随着MACl量的改变,单晶光谱改变幅度很大,说明MACl直接参与合成单晶。然而,当PbCl2量较小时,PbCl2中的C1离子并不参与构成晶体,当PbCl2的量到一定值时,才参与晶体的组成,随着PbCl2的增加,载流子寿命先增加后减小,但是扩散系数并不随着载流子寿命的变化而变化。
[Abstract]:The organic-inorganic hybrid perovskite CH3NH3PbX3 (MAPbX3, XnCl, Br, I) has been widely used in solar cells and other optoelectronic devices due to its high carrier lifetime, high absorption coefficient and high charge mobility (diffusion coefficient). It has become one of the hottest research materials nowadays. The nanocrystalline materials (such as nanowires and nanomaterials) retain the superior photophysical properties of these materials, and their micro and nano dimensions also make the materials have wide application value in the field of micro optoelectronic / optical devices. In this paper, organic and inorganic hybrid perovskite single crystals with different halogens have been synthesized by liquid phase method. By a series of characterization, we have determined that the high quality MAPbX3 (XCBrN I) single crystals have been obtained. The quantitative measurement of carrier diffusion coefficient of micron perovskite single crystal has been completed by the self-constructed fluorescence scanning time-resolved fluorescence imaging system. This method can also be applied to the detection of other optoelectronic materials. On the other hand, by using a laser / fluorescence scanning confocal microscope to measure the local luminescence kinetics and simulate the carrier diffusion process in a single MAPbI3 single crystal, we find that when the perovskite is not uniformly excited, Fast carrier diffusion will accelerate the local photoluminescence kinetics. The results show that the influence of carrier diffusion must be eliminated when the carrier lifetime is analyzed according to the photoluminescence kinetic process in perovskite single crystals. In addition, we compare the effects of Cl sources provided by PbCl2 and MACl on the synthesis of MAPbBr3 single crystals. It is found that the spectrum changes greatly with the change of MACl content, indicating that MACl is directly involved in the synthesis of single crystals. However, when the amount of PbCl2 is small, C1 ions in PbCl _ 2 do not participate in the formation of crystal, but only when the amount of PbCl2 reaches a certain value. With the increase of PbCl2, the carrier lifetime increases first and then decreases. However, the diffusion coefficient does not change with the carrier lifetime.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O73

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