He Wenxin, Hu Jinlong, Chen Chaoran, Chen Yijun, Zeng Linxiang, Zhang Xin, Cai Boyuan, Mai Yaohua, Guo Fei
Institute of New Energy Technology, College of Information Science and Technology, Jinan University, Guangzhou 510632, China.
School of Applied Physics and Material, Wuyi University, Jiangmen 529020, China.
ACS Appl Mater Interfaces. 2020 Dec 16;12(50):55830-55837. doi: 10.1021/acsami.0c15733. Epub 2020 Dec 7.
Formamidinium lead triiodide (FAPbI) exhibits the smallest band gap among lead halide perovskites, which is more desirable for solar cell applications compared to methylammonium-based counterparts. However, it remains a big challenge to prepare phase-pure α-FAPbI in addition to controlling the crystal morphology during film formation. Herein, we developed a temperature-assisted crystal growth to prepare high-quality thin films of α-FAPbI by sequential blade coating. It is found that depositing organic cation FAI at elevated temperatures facilitates the growth of α-FAPbI, which otherwise yields mainly a yellow δ-phase at room temperature. In parallel, the crystal morphology of the perovskite films can be effectively manipulated by taking advantage of the porous structure of PbI. Solar cells prepared with the blade-coated α-FAPbI yield a champion efficiency of 18.41%, which is among the highest values for FAPbI-only solar devices. These results suggest that two-step sequential blade deposition offers a viable approach to fabricate high-quality α-FAPbI films for optoelectronic applications.
碘化甲脒铅（FAPbI）在卤化铅钙钛矿中具有最小的带隙，与基于甲铵的同类材料相比，它在太阳能电池应用中更具优势。然而，除了在成膜过程中控制晶体形态外，制备纯相α-FAPbI仍然是一个巨大的挑战。在此，我们开发了一种温度辅助晶体生长方法，通过连续刮刀涂布制备高质量的α-FAPbI薄膜。研究发现，在高温下沉积有机阳离子FAI有助于α-FAPbI的生长，否则在室温下主要生成黄色的δ相。同时，利用PbI的多孔结构可以有效地控制钙钛矿薄膜的晶体形态。用刮刀涂布的α-FAPbI制备的太阳能电池的最高效率为18.41%，这是仅使用FAPbI的太阳能器件的最高值之一。这些结果表明，两步连续刮刀沉积为制备用于光电子应用的高质量α-FAPbI薄膜提供了一种可行的方法。
