聚芴型共轭聚电解质作为电子传输层应用于太阳能电池

发布时间：2019-03-02 15:01

【摘要】：相比于无机硅太阳能电池,聚合物太阳能电池(PSCs)具有重量轻、价格低、便于携带,柔性好等优点而被国内外研究者关注。虽然经过几十年的发展,聚合物太阳能电池的光电转换效率已经取得了巨大的进展(最高效率已经超过12%),但是在产业化和商业化之前,其器件性能还有待提升。因此,通过设计合成新颖的材料以及制备更加高效的器件结构来进一步优化太阳能电池器件性能显得尤为重要,另外,器件结构中的界面调控对于提高器件的光电转换效率及稳定性也至关重要。优异的界面材料可以在电极/活性层界面形成有利偶极,利于电荷的提取和收集,在聚合物太阳能电池中不仅能减小能级势垒起到关键的作用,还能够改善活性层和相应电极之间的界面接触,最终优化了太阳能电池的性能。本论文设计合成了一系列新型的P型有机电子传输层材料,通过调控界面偶极及能级结构,降低了氧化铟锡(ITO)的功函;另外,通过共轭聚电解质在ITO上的自组装及对上层活性层的诱导,提高了电荷传输性能,最终提高整个太阳能电池的器件性能。众所周知,共轭聚电解质的极性基团可以在电极/活性层界面形成有利偶极,在聚合物太阳能电池中其能减小能级势垒起到关键的作用。因此,我们设计合成了侧链含不同百分数极性胺的共轭聚电解质,基于聚[(9,9-双(3’-(N,N-二甲氨基)丙基)-2,7-芴)-协同-2,7-(9,9-二辛基芴)](PFNs)的衍生物(PFN30,PFN50,PFN70,PFN100),并研究极性基团的数量对界面偶极的影响。仅仅通过改变这些电解质的极性胺数量,界面偶极就可以得到很好地调控。随着极性胺增加,电解质修饰的氧化铟锡功函降低就验证了这一点。另外,增加极性胺的数目也有利于活性层形成光滑均一的形貌。因此PFNs衍生物的极性胺的含量对聚合物太阳能电池的性能产生很大的影响。增加界面层极性胺的数量可以有效地提高器件的效率。在这四个PFNs衍生物中,最高含量极性胺的PFN100在电池中获得了3.27%的效率。这意味着,仅仅通过改变界面层共轭聚电解质极性基团含量是界面工程方面发展高效率聚合物太阳能电池简单易行和有前途的方法。另外,为了进一步优化P型材料,钝化其厚度敏感性,我们还设计合成了另外一系列共轭聚电解质PFB,PFf_1B和PFf_4B替代ZnO作为电子传输层。和PFB电解质不同的是,PFf1B和PFf4B聚合物骨架上分别引入一个氟和四个氟,并以此来调节界面偶极和电荷传输。研究中,我们发现离子和氢氟键诱导的双偶极有益于调节氧化铟锡(ITO)电极的功函。另外,自组装的氟化共轭聚电解质也诱导上层活性层形成理想的纳米线形貌。更有趣的是,在这些共轭聚电解质中发现了氟诱导的电子转移支撑的n型掺杂,从而提高了电子迁移率。结果更进一步显示这些氟化共轭聚电解质在不同活性层的聚合物太阳能电池具有适用性。更值得一提的是,具有最高氟原子含量的PFf4B在厚度达到31.8纳米的时候还能有效地工作,突破了最近报告的共轭聚电解质界面层的厚度限制。综上表明,优化的P型共轭聚电解质在器件中不仅能调控界面偶极及改善电极与活性层的界面接触,还具有很好的自组装性能,而且由于其自掺杂效应能进一步提高电子的传输能力,这对于提高聚合物太阳能电池的器件性能以及以后的大面积生产具有重要的指导意义。
[Abstract]:Compared with the inorganic silicon solar cell, the polymer solar cell (PSCs) has the advantages of light weight, low price, convenient carrying, good flexibility and the like, and is attracted by the researchers at home and abroad. Despite decades of development, the photoelectric conversion efficiency of the polymer solar cell has made great progress (the highest efficiency has been more than 12%), but before the industrialization and commercialization, the device performance of the polymer solar cell is still to be improved. Therefore, it is particularly important to further optimize the performance of the solar cell device by designing a novel material and a more efficient device structure. In addition, the interface regulation in the device structure is also essential for improving the photoelectric conversion efficiency and the stability of the device. the excellent interface material can form an advantageous dipole at the interface of the electrode/ active layer, is beneficial to the extraction and collection of electric charges, not only can reduce the energy level barrier in the polymer solar cell, but also can improve the interface contact between the active layer and the corresponding electrode, And finally the performance of the solar cell is optimized. In this paper, a series of new P-type organic electron transport layer materials were designed, and the work function of tin oxide (ITO) was reduced by controlling the interface dipole and energy level structure. In addition, the self-assembly of the polyelectrolytes on ITO and the induction of the upper active layer were studied. The charge transfer performance is improved, and the device performance of the whole solar cell is finally improved. It is well known that the polar group of the copolyelectrolytes can form an advantageous dipole at the electrode/ active layer interface, which plays a critical role in the reduction of the energy level barrier in the polymer solar cell. Thus, we have designed a copolyelectrolytes containing different percentages of polar amines in the side chain, based on the derivatives of poly[(9,9-bis (3 '-(N, N-dimethylamino) propyl) -2,2,7-1)-co-2,7-(9,9-dioctylphenyl)] (PFNs) (PFN30, PFN50, PFN70, PFN100), And the effect of the number of polar groups on the interface dipole is studied. By changing the number of polar amines of these electrolytes, the interfacial dipole can be well regulated. As the polar amine is increased, this is verified by the reduction in the function of the oxidation of the electrolyte modified by the electrolyte. In addition, increasing the number of polar amines also facilitates the formation of a smooth uniform topography of the active layer. The content of the polar amine of the PFNs derivative thus has a great effect on the performance of the polymer solar cell. Increasing the number of interfacial layer polar amines can effectively improve the efficiency of the device. In these four PFNs derivatives, the PFN 100 with the highest content of polar amine obtained 3.27% efficiency in the cell. This means that it is a simple and promising way to develop high-efficiency polymer solar cells in the aspect of interface engineering only by changing the interfacial layer copolyelectrolytes polar group content. In addition, in order to further optimize the P-type material and to passivate its thickness sensitivity, we also designed a series of co-doped polyelectrolytes PFB, PFf _ 1B and PFf _ 4B instead of ZnO as the electron transport layer. Unlike the PFB electrolyte, a fluorine and four fluorine are introduced into the PFf1B and PFf4B polymer frames, respectively, and thus the interfacial dipole and charge transport are adjusted. In this study, we found that the double-dipole induced by ions and hydrofluorocarbons is useful for adjusting the work function of the tin oxide (ITO) electrode. In addition, self-assembled fluorinated copolyelectrolytes also induce an upper active layer to form an ideal nanowire profile. More interestingly, the n-type doping of the fluorine-induced electron transfer support is found in these copolyelectrolytes, thereby increasing the electron mobility. The results further show the applicability of these fluorinated copolyelectrolytes to polymer solar cells of different active layers. It is more worth mentioning that the PFf4B with the highest fluorine atom content can work effectively when the thickness reaches 31.8 nm, and breaks through the thickness limitation of the common polyelectrolyte interface layer recently reported. It is shown that the optimized P-type co-polymer electrolyte not only can control the interface dipole and improve the interface contact between the electrode and the active layer in the device, but also has good self-assembly performance, and since the self-doping effect can further improve the transmission capability of the electrons, Which is of great significance to the improvement of the device performance of the polymer solar cell and the subsequent large-area production.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM914.4

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