Mixed-Organic-Cation (FA)x(MA)1–xPbI3 Planar Perovskite Solar Cells with 16.48% Efficiency via a Low-Pressure Vapor-Assisted Solution Process

详细信息    查看全文

• 作者：Jing Chen ; Jia Xu ; Li Xiao ; Bing Zhang ; Songyuan Dai ; Jianxi Yao
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2017
• 出版时间：January 25, 2017
• 年：2017
• 卷：9
• 期：3
• 页码：2449-2458
• 全文大小：677K
• ISSN：1944-8252

文摘

Compared to that of methylammonium lead iodide perovskite (MAPbI₃), formamidinium lead iodide perovskite (FAPbI₃) has a smaller energy band gap and greater potential efficiency. To prevent the transformation of α-FAPbI₃ to δ-FAPbI₃, preparation of (FA)_x(MA)_1–xPbI₃ was regarded as an effective route. Usually, the planar (FA)_x(MA)_1–xPbI₃ perovskite solar cells are fabricated by a solution process. Herein, we report a low-pressure vapor-assisted solution process (LP-VASP) for the growth of (FA)_x(MA)_1–xPbI₃ perovskite solar cells that features improved electron transportation, uniform morphology, high power conversion efficiency (PCE), and better crystal stability. In LP-VASP, the (FA)_x(MA)_1–xPbI₃ films were formed by the reaction between the PbI₂ film with FAI and MAI vapor in a very simple vacuum oven. LP-VASP is an inexpensive way to batch-process solar cells, avoiding the repeated deposition solution process for PbI₂ films, and the device had a low cost. We demonstrate that, with an increase in the MAI content, the (101) peak position of FAPbI₃ shifts toward the (110) peak position of MAPbI₃, the (FA)_x(MA)_1–xPbI₃ perovskites are stable, and no decomposition or phase transition is observed after 14 days. The photovoltaic performance was effectively improved by the introduction of MA⁺ with the highest efficiency being 16.48% under conditions of 40 wt % MAI. The carrier lifetime of (FA)_x(MA)_1–xPbI₃ perovskite films is approximately three times longer than that of pure FAPbI₃. Using this process, solar cells with a large area of 1.00 cm² were fabricated with the PCE of 8.0%.