下转换材料合成及其在新型太阳电池中的应用研究

发布时间：2018-03-14 03:15

本文选题：太阳电池　切入点：钙钛矿　出处：《中国科学技术大学》2017年博士论文　论文类型：学位论文

【摘要】：钙钛矿太阳电池作为一种新型太阳电池,具有生产成本低、制备工艺简单、电迁移率高、吸光系数大等优点。自诞生以来,就以惊人的速度刷新着效率记录,是太阳能技术的一个重大革新。受带隙宽度的限制,常规钙钛矿太阳电池只能吸收占太阳总辐射光谱44%左右的可见光,这导致电池吸收带隙与入射太阳光谱不匹配,造成能量损失,限制了效率的提升。此外,具有较高能量的紫外光,会造成电池结构一定程度的破坏,导致电池光电性能下降。采用紫外虑光膜虽然避免了紫外光对电池的损害,提高了电池的稳定性,但也使电池无法有效利用紫外光,减小了电池的光采集效率。本论文从拓宽电池光谱响应范围提高效率及稳定性的角度出发,采用稀土下转换材料将高能量紫外光转换成低能量可见光,使其与电池的吸收光谱更加匹配,实现电池对入射太阳光的有效利用,同时减小紫外光诱导降解对电池性能的影响。稀土配合物作为一种优良的发光材料,具有发光效率高、吸收范围广、荧光寿命长等优点。在提高电池光利用率及性能方面,具有很好的应用前景。本文对提高配合物发光性能、拓宽吸收范围进行了研究,并择优选取配合物应用于钙钛矿太阳电池中,系统研究了配合物下转换发光与电池性能之间的关系。此外,将易激发、量子效率高的Eu3+离子与介孔Ti02结合,进一步降低电池内部紫外光诱导降解,提高电池光采集效率。为提高稀土配合物的发光性能,在Phen-Eu(III)体系中引入乙二胺,调控发光中心(Eu3+离子)周围微化学环境。通过分析配合物的光学性能发现,乙二胺的添加含量小于或者等于0.2 mmol时,配合物的荧光强度明显提高。但是过量的乙二胺与发光中心配位,会使发光中心趋于配位饱和,导致配体与发光中心之间的配位变困难,阻碍了配体向发光中心的有效能量传递,引起配合物的荧光性能下降。通过在配体(1,10-邻菲罗啉)上引入不同特性取代基(5-硝基、5-甲基、4,7-二甲基、4,7-甲氧基和4,7-二苯基)改变配体结构,研究不同结构下配合物的发光性能。结果表明,供电子基团及共轭基团能够提高配合物电子云密度,使电子跃迁能级降低,增大配合物的紫外吸收系数。此外,这种取代基效应及共轭效应有助于提高配体与发光中心间的能级匹配程度,有效提升铕配合物分子内的能量传递效率,从而增强了配合物的发光性能。选取紫外吸收能力强、发光强度大的配合物(铕-4,7-苯基-1,10-邻菲罗啉)制成透明光转换薄膜,采用下转换层前置模型应用在电池上,提高了电池的光采集效率,获得了 11.8%的电流增益,光电转换效率达到15.44%。紫外光照10 h后,仍保持了初始效率的74%,稳定性明显提高。为提高电池紫外光利用率,进一步降低内部紫外光诱导降解,将Eu引入介孔TiO2半导体制备TiO2:Eu3+下转换发光材料,作为骨架层应用到钙钛矿太阳电池中。采用SEM、XRD、XPS和荧光光谱等表征手段深入研究了 TiO2:Eu3+下转换发光材料的晶体结构和发光性能。发现Eu3+离子没能掺杂到TiO2晶格中,而是附着在TiO2晶面上。同时TiO2能够诱导Eu3+离子发光,实现电池对紫外光的有效利用。电池的光伏数据分析表明,Eu掺杂TiO2可以增强电池的紫外光捕获效率,降低电池中TiO2产生的电子-空穴对对钙钛矿材料的氧化还原作用,同时抑制电子-空穴复合,提高电池开路电压,从而使电池获得更高的光电转换效率及紫外稳定性。然而过量掺杂Eu会使TiO2的晶界缺陷增加,TiO2中电子与CH3NH3PbI3中空穴复合的几率变大,不利于TiO2中的电子传输。
[Abstract]:Perovskite solar battery is a new type of solar cell, has the advantages of low production cost, simple preparation, high mobility, absorption coefficient and other advantages of light. Since its birth, at an alarming rate refresh efficiency record, is a major innovation in solar technology. The band gap width limit, only routine perovskite solar absorption accounted for about 44% of the total solar radiation spectrum of visible light, which leads to cell absorption band gap and incident solar spectrum do not match, resulting in energy loss, limiting the efficiency. In addition, ultraviolet light has high energy, will cause the battery structure to a certain degree of damage, resulting in a decline in the photovoltaic performance by UV. Consider light film while avoiding the damage of UV on the battery, improves the stability of the battery, but also make the battery can not effectively use ultraviolet light, reduce the light collection efficiency of the battery. In this thesis, broaden the power The spectral response range of pool to improve the efficiency and stability of the perspective of using rare earth conversion materials will be converted into low energy high energy ultraviolet visible light, and the absorption spectrum of the battery more matching, to achieve efficient use of battery incident solar light, reduce the effect of UV induced degradation of cell performance. At the same time as rare earth complexes a kind of excellent luminescent materials, high luminous efficiency, wide range of absorption, fluorescence has the advantages of long service life. In the aspect of improving the battery light utilization rate and performance, has good application prospects. This paper to improve the luminous properties of complexes were studied, to broaden the range of absorption and ativity complexes used in perovskite in the solar cell system, studies the relationship between the complexes of conversion and cell performance. In addition, the easy to stimulate, Eu3+ ion and mesoporous Ti02 with high quantum efficiency, further reduced The internal battery UV induced degradation, improve the battery light collection efficiency. In order to improve the luminescence properties of rare earth complexes, Phen-Eu (III) into the ethylenediamine system, regulation of the luminescent center (Eu3+ ion) around the micro chemical environment. Through the analysis of the optical properties with the discovery, the content of ethylenediamine is less than or equal to 0.2 mmol, with the the fluorescence intensity increased significantly. But excessive ethylenediamine and luminescence center coordination, the coordination center of light tends to be saturated, causes between the ligand and the luminescent center coordination becomes difficult, hampered the effective energy transfer from ligand light center, decrease the fluorescence properties of the complexes. The ligand (1,10- o phenanthroline) on the introduction of different characteristics of substituents (5- nitro, 5- methyl 4,7-, methyl two, 4,7- two and 4,7- methoxy phenyl) change the ligand structure, luminescent properties of complexes of different structure. The results show that the electron donating group and conjugated complexes can improve the electron density, the electron transition energy level decreases and the UV absorption coefficient increase complexes. In addition, the substituent effect and conjugated effect is helpful to improve the level of luminescence center between the ligand and the matching degree, effectively improve the transfer efficiency of molecules within the EU the energy cooperation, so as to enhance the luminescence properties of the complexes. The selection of UV absorption ability, the luminescence intensity of complexes (europium -4,7- phenyl -1,10- phenanthroline) made of transparent light conversion film, pre conversion layer model is used in the battery use, improve the light collection efficiency of the battery, the current gain 11.8%, the photoelectric conversion efficiency reached 15.44%. after 10 h of UV light, still maintain the initial efficiency of 74%, significantly improve the stability. In order to improve the utilization of the battery to further reduce internal UV light, UV light induced reduction Solution, luminescent materials Eu into mesoporous TiO2 semiconductor fabrication of TiO2:Eu3+ conversion, as the skeleton layer applied to the perovskite solar cell. By using SEM, XRD, XPS and fluorescence spectra research TiO2:Eu3+ down conversion crystal structure and luminescence properties of luminescent materials. We can't Eu3+ ion doped into the TiO2 lattice but, attached to the TiO2 surface. At the same time, TiO2 can induce luminescence of Eu3+ ions, realize the effective utilization of the battery to ultraviolet. The photovoltaic battery data analysis shows that Eu doped TiO2 can enhance cell UV capture efficiency, reduce the oxidative electron hole cell TiO2 on the perovskite material reduction, and suppression the electron hole recombination, improve the open circuit voltage of the cell, so that the battery photoelectric conversion efficiency and UV stability higher. However, excessive Eu doping makes grain boundary defects increase of TiO2, TiO The probability of cavity recombination between 2 and 2 electrons in CH3NH3PbI3 becomes larger and is not conducive to electronic transmission in TiO2.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O641.4;TM914.4

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