高效反式钙钛矿太阳能电池的器件优化及其大面积制备

DEVICE OPTIMIZATION AND LARGE-SCALE FABRICATION OF EFFICIENT INVERTED PEROVSKITE SOLAR CELLS

王登

11849237

硕士

材料学

徐保民

2020-05-30

2020-07-01

哈尔滨工业大学

深圳

随着各世界各国的工业化不断完善，地球上的传统化石能源被大量消耗，所以开发新型的可再生能源便成为了能源研究的焦点。太阳能电池将光能转化成电能的方式具有能量转换率高且易于储存的优点，被普遍认为是高效利用太阳能的最佳方式。其中钙钛矿太阳能电池因为其成本低廉、可柔性制备、转化效率高等特点引起了研究者们的广泛关注。尽管目前最高效的钙钛矿器件主要基于平面正式结构和介孔正式结构，但是反式结构具有制备工艺简单和易与传统太阳能电池结合制备叠层电池等优势，为今后的商业化生产开拓了广阔的前景。因此，本论文将围绕反式钙钛矿太阳能电池的器件优化展开研究，并扩展到大面积器件的制备，主要工作如下：我们开发了新型的有机小分子空穴传输材料 TMeOPSIDA 和 TMePSIDPA。相比于 PEDOT：PSS，TMeOPSIDA 和 TMePSIDPA 的 HOMO 能级与钙钛矿的价带更为匹配，有利于界面间电荷的抽取并提高器件的开路电压。其中，TMePSIDPA比 TMeOPSIDA 的空穴迁移率更高，代表着具有更好的空穴传输能力。从扫描电子显微镜（SEM）表面图像来看，相比于 PEDOT：PSS，基于小分子材料的钙钛矿薄膜拥有更大的晶粒尺寸。通过对 TMePSIDPA 的溶液浓度和退火温度进行优化，使器件性能优化到了 19.41%的转换效率，稳定性测试也证明了基于 TMePSIDPA的器件在保存相同时间内能够维持更高的初始效率。两性离子 BTCC（bethanechol chloride）的引入，能够通过形成氢键附着于钙钛矿的表面，并对多种类型的缺陷进行钝化，包括 MA 离子和 I 离子的空位以及未配对的铅离子缺陷。稳态 PL 和瞬态 PL 测试证实了 BTCC 能够有效钝化钙钛矿中的缺陷，抑制载流子的非辐射复合和延长载流子的寿命。通过优化 BTCC 的最佳质量分数为 1%，基于 PTAA 制备的器件转化效率达到 20.45%，而基于小分子TMePSIDPA 空穴传输材料的器件效率能达到 21.12%，进一步证实了这项优化工艺的普适性。并且，BTCC 的引入对器件的长期稳定性也大有改善，经过 BTCC 处理的器件在空气环境下保存 800 h 后，仍然具有原始效率的 82%。我们采用刮刀涂布法对反式结构器件实现印刷制备。往前驱体溶液中添加适当比例 DMSO 溶剂，由于其较高的沸点和铅离子的配位作用，加热时更难从溶剂中去除，可以起到延缓结晶和调控结晶的作用。通过对基于不同的比例 DMSO 的器件进行 J-V 测试，可以发现当 DMF:DMSO=8.5:1.5 时，器件的整体得到显著提升，效率从 10.98 跃升至 13.83%。基于无机 NiOx空穴传输层的器件将器件效率进一步提升到 15.34%，最明显的提升在于开路电压，这是因为相较于 PEDOT：PSS，NiOx 与钙钛矿的能级更为匹配。并且，NiOx 良好的薄膜润湿性可以进一步提高溶液的利用率，非常适合今后的大规模生产。结合优化方案，我们最终用刮涂法实现了效率为 2.97%的 10 cm×10 cm 大面积组件的制备。

With the continuous improvement of industrialization in various countries, the traditional fossil energy on the earth has been consumed in large quantities, so the development of renewable energy has become the focus of energy research. Solar cells convert light energy into electrical energy, which has the advantages of high energy conversion rate and easy storage. It is generally considered to be the best way to efficiently use solar energy. Among them, perovskite solar cells (PSCa) have attracted extensive attention from researchers because of their low cost, flexible manufacturing, and high conversion efficiency. Although currently the most efficient PSCs are mainly based on planar regular structure and mesoporous regular structure, the inverted structure has the advantages of simple preparation process and easy combination with traditional solar cells to prepare laminated devices, which opens up for future commercial production. Therefore, this paper will focus on the device optimization of inverted PSCs and expand to the preparation of large-area devices. The main work is as follows:We have developed new organic small molecule hole transport materials (HTMs) TMeOPSIDA and TMePSIDPA. Compared to PEDOT: PSS, the HOMO energy level of TMeOPSIDA and TMePSIDPAis more closely matched to the valence band of perovskite, which is beneficial to the extraction of charge between interfaces and improves the open circuit voltage (VOC) of the device. Among them, TMePSIDPA has a higher hole mobility than TMeOPSIDA, which represents a better hole transport capability. From the SEM surface image, the perovskite thin film based on small molecular materials has a larger grain size. By optimizing the solution concentration and annealing temperature of TMeOPSIDA, the device performance is optimized to a power conversion efficiency (PCE) of 19.41%, and the stability test also proves that the device based on TMeOPSIDA can maintain a higher initial efficiency during the same storage time.The introduction of zwitterionic BTCC (bethanechol chloride) can attach to the surface of perovskite by forming hydrogen bonds and passivate various types of defects, including vacancies of MA ions and I ions and under-coordinated lead ion defects. The steady state PL and transient PL tests confirmed that BTCC can effectively passivate the defects in perovskite, suppress the non-radiative recombination of carriers and extend the life of carriers. By optimizing the mass ratio of BTCC to be 1%, the PCE of devices prepared based on PTAA reached 20.45%, and the pce based on the small molecule TMeOPSIDA HTM could reach 21.12%, further confirming the universality of this optimization process. In addition, the introduction of BTCC has greatly improved the long-term stability of the device. After BTCC treatment, the device still has 82% of the original efficiency after being stored in the ambient environment for 800 h. We adopt the doctor blade-coating method to realize the printing preparation of inverted-strcuture devices. Adding a suitable content of DMSO solvent to the precursor solution, due to its higher boiling point and coordination of lead ions, it is more difficult to remove from the solvent, which can play a role in delaying crystallization and regulating crystallization. By conducting J-V tests on devices based on different ratios of DMSO, we can find that when DMF: DMSO=8.5: 1.5, the overall device is significantly improved, and the PCE jumps from 10.98 to 13.83%. The device based on the inorganic NiOx hole transport layer further improves the device efficiency to 15.34%. The most obvious improvement is theVOC, because the energy level of NiOx and perovskite is more matched than that of PEDOT: PSS. Moreover, the good film wettability of NiOx can further improve the utilization rate of the solution, which is very suitable for future largescale production. Combined with the optimization plan, we finally achieved the preparation of 10 cm×10 cm large-area modules with a PCE of 2.97% using the bladecoating method.

钙钛矿太阳能电池 平面反式结构 空穴传输材料 缺陷钝化 刮刀涂布法 大面积组件

perovskite solar cells inverted structure hole-transport materials defect passivation blade-coating method large-area modules

中文

联合培养

南方科技大学

王登. 高效反式钙钛矿太阳能电池的器件优化及其大面积制备[D]. 深圳. 哈尔滨工业大学,2020.