Wu Yongzhen, Chen Wei, Yue Youfeng, Liu Jian, Bi Enbing, Yang Xudong, Islam Ashraful, Han Liyuan
Photovoltaic Materials Unit, National Institute for Materials Science , Sengen 1-2-1, Tsukuba, Ibaraki 305-0047, Japan.
State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University , 800 Dong Chuan Road, Shanghai 200240, China.
ACS Appl Mater Interfaces. 2015 Sep 23;7(37):20707-13. doi: 10.1021/acsami.5b05576. Epub 2015 Sep 9.
Perovskite solar cells have shown high photovoltaic performance but suffer from low reproducibility, which is mainly caused by low uniformity of the active perovskite layer in the devices. The nonuniform perovskites further limit the fabrication of large size solar cells. In this work, we control the morphology of CH3NH3PbI3 on a mesoporous TiO2 substrate by employing consecutive antisolvent dripping and solvent-vapor fumigation during spin coating of the precursor solution. The solvent-vapor treatment is found to enhance the perovskite pore filling and increase the uniformity of CH3NH3PbI3 in the porous scaffold layer but slightly decrease the uniformity of the perovskite capping layer. An additional antisolvent dripping is employed to recover the uniform perovskite capping layer. Such consecutive morphology controlling operations lead to highly uniform perovskite in both porous and capping layers. By using the optimized perovskite deposition procedure, the reproducibility of mesostructured solar cells was greatly improved such that a total of 40 devices showed an average efficiency of 15.3% with a very small standard deviation of 0.32. Moreover, a high efficiency of 14.9% was achieved on a large-size cell with a working area of 1.02 cm(2).
钙钛矿太阳能电池已展现出高光伏性能，但存在可重复性低的问题，这主要是由器件中活性钙钛矿层的低均匀性所致。不均匀的钙钛矿进一步限制了大尺寸太阳能电池的制造。在这项工作中，我们通过在前驱体溶液旋涂过程中采用连续反溶剂滴加和溶剂蒸汽熏蒸的方法，来控制介孔TiO₂衬底上CH₃NH₃PbI₃的形貌。发现溶剂蒸汽处理可增强钙钛矿的孔隙填充，并提高多孔支架层中CH₃NH₃PbI₃的均匀性，但会略微降低钙钛矿覆盖层的均匀性。采用额外的反溶剂滴加来恢复均匀的钙钛矿覆盖层。这种连续的形貌控制操作使得多孔层和覆盖层中的钙钛矿都高度均匀。通过使用优化的钙钛矿沉积工艺，介观结构太阳能电池的可重复性得到了极大提高，以至于总共40个器件的平均效率为15.3%，标准偏差非常小，仅为0.32。此外，在工作面积为1.02 cm²的大尺寸电池上实现了14.9%的高效率。
