平面异质结结构钙钛矿太阳电池的研究

发布时间：2018-04-03 14:11

本文选题：钙钛矿太阳电池　切入点：平面异质结结构　出处：《宁波大学》2015年硕士论文

【摘要】：近年来,以甲胺基铅碘化合物(CH3NH3PbI3)为代表的有机-无机杂化钙钛矿材料成为光伏领域的新“明星”。基于此类材料的太阳电池的能量转换效率经过5年的发展从2009年的3.8%极速攀升到目前新闻报道的20.1%,效率进步之快令人赞叹。更重要的是,钙钛矿原料丰富价格低廉,可溶液制备大面积、柔性光电器件。针对高质量的钙钛矿薄膜及太阳电池器件制备的可重复性差、器件稳定性差等问题,我们探索了高质量、高覆盖率、良好可重复性钙钛矿薄膜的制备工艺,实现了具有高效率、良好可重复性、较好稳定性的平面异质结结构钙钛矿太阳电池的制备。本文的主要内容:1.通过比较两种不同的退火方法(一步直接退火法和多步缓慢退火法)制备的CH3NH3PbI3-xClx钙钛矿薄膜的结构形貌、光电特性及对应器件的光伏性能,我们发现多步缓慢退火法是一种普适的可以制备高效可重复的平面异质结结构钙钛矿太阳电池的有效方法。采用这种方法制备的平面异质结结构钙钛矿太阳电池给出了13.58%的最高效率,相较于一步直接退火法制备的器件8.65%的效率提升了57%。我们提出的优化了的退火方法可以保证高质量的钙钛矿薄膜的可重复性制备。2.通过进一步精细地控制退火温度和时间,我们得到了几乎100%覆盖率和晶体高度取向的CH3NH3PbI3-xClx钙钛矿薄膜。由此,制备出了平均效率12.0%、最高效率15.17%的平面异质结结构钙钛矿太阳电池。高覆盖率保证了充分的光吸收,避免了可能的短路发生。高度取向的晶体非常有利于电子和空穴高效地向各自对应的电极输运。鉴于此方法制备的薄膜高度的晶体取向性,各向异性的电子传输特性模型首次提出用以解释所观察到的优良的光伏性能。在此制备方法的基础上,通过对其他功能层的优化可以预期更好的器件性能。3.针对常规平面异质结结构器件稳定性比较差的问题,展开实验并发现了部分原因。掺入spiro-Me OTAD中的各种溶剂和溶质都多少对钙钛矿具有溶解和破坏作用,特别是极易吸湿的锂盐(Li-TFSI)通过吸收空气中的湿气而对钙钛矿进而整个器件性能具有很大的破坏作用,乙腈也有溶解和分解钙钛矿的作用。作为替换,采用与spiro-Me OTAD共溶于氯苯的强氧化剂F4-TCNQ作为空穴传输层的p型掺杂剂,成功制备出最高效率10.59%的平面异质结结构钙钛矿太阳电池,而且器件具有比基于Li-TFSI掺杂spiro-Me OTAD作为空穴传输层的同类器件具有更好的稳定性。
[Abstract]:In recent years, organic-inorganic hybrid perovskite materials, represented by methylamino lead iodide (Ch _ 3NH _ 3PbI _ 3), have become a new "star" in photovoltaic field.The energy conversion efficiency of solar cells based on such materials has climbed from 3.8 percent in 2009 to 20.1percent in current news reports after five years of development.More importantly, perovskite raw materials are cheap and can be used to prepare large area flexible optoelectronic devices.In order to solve the problems of poor repeatability and stability of high quality perovskite thin films and solar cell devices, we have explored the preparation process of high quality, high coverage and good repeatability perovskite films, and achieved high efficiency.Preparation of planar heterojunction perovskite solar cells with good repeatability and stability.The main content of this paper is: 1.CH3NH3PbI3-xClx perovskite films prepared by two different annealing methods (one step direct annealing method and multi step slow annealing method) were compared in terms of their structure morphology, photoelectric properties and photovoltaic properties of the corresponding devices.We find that the multistep slow annealing method is an effective method for fabricating high efficient and repeatable planar heterojunction perovskite solar cells.The maximum efficiency of the planar heterojunction perovskite solar cells fabricated by this method is 13.58%, which is 57% higher than the 8.65% efficiency of the devices fabricated by one-step direct annealing.The optimized annealing method can guarantee the repeatability of perovskite thin films with high quality.CH3NH3PbI3-xClx perovskite thin films with nearly 100% coverage and high crystal orientation have been obtained by further controlling annealing temperature and time.As a result, a planar heterojunction perovskite solar cell with an average efficiency of 12.0 and a maximum efficiency of 15.17% was prepared.High coverage ensures adequate light absorption and avoids possible short-circuiting.Highly oriented crystals are conducive to the efficient transport of electrons and holes to their respective electrodes.In view of the high crystal orientation of the films prepared by this method, the anisotropic electron transport model is proposed for the first time to explain the observed excellent photovoltaic properties.On the basis of this preparation method, the better device performance. 3 can be expected by optimizing the other functional layers.In order to solve the problem of poor stability of conventional planar heterojunction devices, experiments are carried out and some reasons are found.All kinds of solvents and solutes mixed with spiro-Me OTAD can dissolve and destroy perovskite, especially Li-TFSIs, which are easy to absorb moisture, which can destroy perovskite and the whole device performance by absorbing moisture in air.Acetonitrile also dissolves and decomposes perovskite.Instead, using F4-TCNQ, a strong oxidant co-soluble in chlorobenzene with spiro-Me OTAD, as the p-type dopant of the hole transport layer, a planar heterojunction perovskite solar cell with the highest efficiency of 10.59% was successfully prepared.And the device has better stability than the same device based on Li-TFSI doped spiro-Me OTAD as the hole transport layer.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM914.4

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