Mie散射增强的新型石墨烯光电探测器研究及Mie散射应用拓展

发布时间：2018-01-04 22:01

本文关键词：Mie散射增强的新型石墨烯光电探测器研究及Mie散射应用拓展　出处：《南京大学》2015年硕士论文　论文类型：学位论文

【摘要】：石墨烯具有狄拉克锥形能带结构、稳定的化学性质、超快的电子传输速率,已经成为基于新型二维材料的高性能光电探测器件的重要材料。但是由于石墨烯中不存在能隙,无法形成异质结,因此其光生载流子分离困难,且复合率较高。本论文针对这个问题,通过微球Mie散射提高石墨烯光电探测器的光吸收、光生载流子分离效率和探测灵敏度。同时,拓展研究了利用Mie散射提高太阳能电池的光吸收从而提高其光电转换效率。主要工作如下：(1)基于微球的Mie散射效应,利用FDTD仿真软件设计了一种新型的石墨烯光电探测器,研究了颗粒材料、尺寸,激光波长等参数对光场分布的影响,发现Mie散射微球对光场用明显的调控作用,可以在探测器中引入非对称的光场势差。(2)制备了基于微球的Mie散射效应的新型石墨烯光电探测器,研究了石墨烯探测器相关的制备工艺和微球引入后对石墨烯探测器性能的影响。利用CVD方法生长的大面积石墨烯,通过微加工手段在石墨烯表面制备电极并测量石墨烯的本身光电性能;通过溶液分散滴加法将TiO2微纳级联结构微球及Si微球置入石墨烯探测器电极之间,获得了新型的石墨烯光电探测器,并研究了其光电性能。实验结果表明,利用Mie散射微球增强的石墨烯光电探测器的光电流增大了300%,表明利用Mie散射结构将光场势差引入石墨烯光电探测器可以提高载流子分离效率,增大光电流。(3)对Mie散射提高太阳能电池光电转换效率进行了实验探索。利用新型的氧化物球形级联结构的制备方法获得了Ti02微纳级联结构微球,并制备了基于Ti02微纳级联结构微球的染料敏化太阳能电池。微球的Mie散射效应可以提高DSSCs中光阳极的光吸收效率,从而提高光电池的光电转换效率。实验中通过烧结温度调控纳米颗粒之间的接触面积,进而对染料敏化太阳能电池的性能进行了优化,发现烧结温度为450℃为最优化工艺条件,其电池效率相比温度其它条件制备的电池至少提高了12.3%。
[Abstract]:Graphene has Dirac tapered band structure, stable chemical properties, ultrafast electron transfer rate, has become an important material of high performance photoelectric detector model based on a two-dimensional material. But because the energy gap does not exist in graphene, cannot form heterojunction, therefore the separation of photogenerated carriers is difficult, and high recombination rate. This paper is aimed at this problem, improve the graphene photodetector light absorption by the micro Mie scattering, photogenerated carrier separation efficiency and detection sensitivity. At the same time, expand the research using Mie scattering to improve the light absorption of solar cells to improve the photoelectric conversion efficiency. The main work is as follows: (1) Mie scattering microspheres based on design a new type of graphene photodetector using the FDTD simulation software, the size of the granular material, the wavelength of the laser parameters on the optical field distribution of the influence of Mie powder The obvious regulation by shot microspheres on optical field in the detector can introduce light field potential asymmetric difference. (2) preparation of novel graphene photodetector Mie scattering microspheres based on the study of influence on the performance of graphene graphene detector detector into the preparing process and microspheres large area graphene grown by CVD method, through its photoelectric properties of micro machining tools in Shi Moxi surface electrode preparation and measurement of graphene; dropping by solution dispersion between TiO2 micro nano microspheres and Si microspheres in the cascade structure of graphene electrode probe, obtained graphene photodetector model, and Study on the photoelectric properties. The experimental results show that the graphene photodetector enhanced by Mie scattering microspheres light current increases by 300%, the results indicate that the Mie scattering structure light field potential difference into graphene optoelectronic The detector can improve the carrier separation efficiency, increase the photocurrent of Mie scattering. (3) improve the photoelectric conversion efficiency of solar cell were studied. The preparation method of oxide spherical new cascaded structure obtained by Ti02 micro nano microsphere cascade structure, and dye-sensitized solar cell based on the preparation of Ti02 micro nano microsphere cascade structure the Mie scattering effect of microspheres can improve the light absorption of the light anode efficiency in DSSCs, so as to improve the photoelectric conversion efficiency of the battery light. The contact area between the sintering temperature regulation of the nanoparticles, and the performance of dye-sensitized solar cells were optimized, sintering temperature is 450 DEG C for the optimization of process conditions, the battery efficiency compared to other conditions for preparation of the battery temperature increase of at least 12.3%.

【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN36;O613.71

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