Li Yi-Ming, Chung Ho-Yang, Liao Cheng-Wei, Prabu Samikannu, Wang Hong-Wen
Department of Chemistry, Chung-Yuan Christian University, Chungli, 320, Taoyuan, Taiwan, R.O.C.
J Nanosci Nanotechnol. 2019 Jan 1;19(1):112-118. doi: 10.1166/jnn.2019.16437.
A light harvest layer composed of gradual change from formamidinium lead triiodide (FAPbI₃) to methylammonium lead triiodide (MAPbI₃) was fabricated using a novel two-step process. That is, a graded halide layer structure without extra processing steps is demonstrated. Conventionally, in the fabrication of MAPbI₃ perovskite solar cells (PSCs) using two-step process, PbI₂ layer was the first deposited on a mesoporous TiO₂ coated substrate. The methylammonium iodide (MAI) solvent was then spin-coated on the surface of PbI₂ layer and heated to form the MAPbI₃ perovskite layer. Double perovskite layers such as FAPbI₃ plus MAPbI₃ requires twice of the second step which FAI and MAI should be spin-coated individually. This can be tedious and time consuming. We report here a facile way to form a graded perovskite layer, consisting FAPbI₃ to MAPbI₃, in a single step. FAI was first added into dimethylformamide (DMF) solution that was used to form PbI₂ layer, then MAI solution was dripped on top of the FAI/PbI₂ layer. The graded perovskite layer structure (FAPbI₃/MAPbI₃) in a gradient manner are readily formed, where the structure is confirmed by EDS to be FTO/compact TiO₂/mesoporous TiO₂/FAPbI₃(thin)/MAPbI₃/Spiro-OMeTAD/Ag. The , and of solar cells with this graded perovskite layer are enhanced and the efficiency increases from 11.62% to 14.06%.
采用一种新颖的两步法制备了由甲脒铅三碘化物（FAPbI₃）到甲基铵铅三碘化物（MAPbI₃）渐变组成的光捕获层。也就是说，展示了一种无需额外加工步骤的分级卤化物层结构。传统上，在使用两步法制备MAPbI₃钙钛矿太阳能电池（PSC）时，PbI₂层首先沉积在涂有介孔TiO₂的基板上。然后将甲基碘化铵（MAI）溶剂旋涂在PbI₂层表面并加热以形成MAPbI₃钙钛矿层。诸如FAPbI₃加MAPbI₃的双钙钛矿层需要进行两次第二步操作，即FAI和MAI应分别旋涂。这可能既繁琐又耗时。我们在此报告一种简便的方法，可在一步中形成由FAPbI₃到MAPbI₃组成的渐变钙钛矿层。首先将FAI添加到用于形成PbI₂层的二甲基甲酰胺（DMF）溶液中，然后将MAI溶液滴加到FAI/PbI₂层上。以渐变方式容易形成渐变钙钛矿层结构（FAPbI₃/MAPbI₃），通过能谱仪（EDS）确认该结构为FTO/致密TiO₂/介孔TiO₂/FAPbI₃（薄）/MAPbI₃/螺环-OMeTAD/Ag。具有这种渐变钙钛矿层的太阳能电池的开路电压、短路电流密度和填充因子得到提高，效率从11.62%提高到14.06%。
